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GNEERMANUAL EM1110-2-41031 Dec 1982

ENGNEERINGANDDESIGN

DESIGNOFRECREATIONAREASANDFACILITIES-ACCESSANDCIRCULATION

DEPARTMENTOFTHEARMYCORPSOFENGNEERSOFFICEOFTHECHEF OFENGNEERS


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DEPARTMENT OF THE ARMY EM 1110-2-410US Army Corps of Engi neersDAEN-CWE-BU Washi ngton, D. C. 20314

ManualNo . 1110-2-410

Engi neeri ng and Desi gnDESIGNOF RECREATION AREAS AND FACI LITI ESACCESS ANDCIRCULATION

31 December 1982

1 . Purpose . The purpose of thi s manual i s t o present data compi l ed f romexperi ence and research that shoul d be useful i n the desi gn of access andci rcul ati on t o recreati on si tes, areas and faci l i ti es .2 . Appl i cabi l i ty . Thi s manual i s appl i cabl e t o al l fi el d operati ngacti vi ti es havi ng ci vi l works desi gn responsibi l i ti es .3 . Dscussi on. Access and ci rcul ati on t o and through park andrecreati on areas have di sti ncti ve characters and pl ay a maj or rol e i ni nf l uenci ng the publ i c' s enj oyment of recreati on resources . Each segmentof the faci l i ty shoul d be compati bl e wth the envi ronment and therecreati on scene through whi ch i t passes . Usi ng thi s phi l osophy, thi smanual presents basi c design consi derati ons for al l porti ons and modes ofaccess and ci rcul ati on t o and about recreati on areas and faci l i ti es . I tsets out speci f i c desi gn consi derati ons whi ch when appl i ed can el imnateconfusi on and dupl i cati on of desi gn ef fort . An attempt i s made to .present the most ef f i ci ent, practi cal and time tested desi gns .Addi ti onal gui dance i s gi ven i n the formof constructi on detai l s and byi l l ustrati ons of exi sti ng desi gn sol uti ons . The i l l ustrati ons weresel ected for thei r soundness and completeness for meeti ng the publ i c needfor recreati on faci l i ti es .FOR THE COMMANDER

ES W WAYCol onel , Corps of Engi neersChi ef of Staf f


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DEPARTMENT OF THE ARMY EM 1110-2-410US Army Corps of Engi neersDAEN-CWE-BU Wshi ngton, D C. 20314ManualNo . 1110-2-410 31 December 1982

Engi neeri ng and Desi gnDESIGNOF RECREATIONAREAS AND FACILITI ES - ACCESS AND CRCULATION

CHAPTER 1

CHAPTER 2

Tabl e of ContentsSub ect Paragraph PageI NTRODUCTIONPurpose-- -- -- -- -- -- -- -- -- -- -- -- -- -- 1-1 1-1Appl i cabi l i ty-- -- -- -- -- -- -- -- -- -- -- 1-2 1-1References-- -- -- -- -- -- -- - -- -- -- -- -- 1-3 1-1Scope-- -- -- -- -- -- -- -- -- -- -- -- -- -- - 1-4 1-2Dscussi on-- -- -- -- -- -- -- -- -- -- -- -- - 1-5 1-2ROADSAppl i cati on-- -- -- -- -- -- -- -- -- -- -- -- 2-1 2-1Control s-- -- -- -- -- -- -- -- -- -- -- -- -- - 2-2 2-1Topography and Physi cal Features- 2-2a 2-1Road C assi f i cati ons-- -- -- -- -- -- - 2-2b 2-2Traff i c--- --- --- --- --- --- --- --- -- 2-2c 2-3Vehi cl e Characteri sti cs ---------- 2-2d 2-4Capaci ty-- -- -- -- -- -- -- -- -- -- -- -- - 2-2e 2-4Safety------------------------ 2-2f 2-5Cost--- --- --- --- --- --- --- --- --- -- 2-2g 2-5Elements of Desi gn-- - - - - - - - - - - - - - - 2-3 2-5Desi gn Speed-- -- -- -- - -- -- -- -- -- -- 2-3a 2-5Si ght Dstance-- -- -- -- -- -- -- -- -- - 2-3b 2-6Hori zontal A i gnment- -- -- -- - -- -- - 2-3c 2-8Verti cal Al ignment-Profi les--- 2-3d 2-13Combi nati on of Hori zontal andVerti cal Al i gnment-- - - - - - - - - - - 2-3e 2-17Drai nage and Erosi on Control -- -- - 2-3f 2-18Landscape Devel opment-- - - - - - - - - - 2-3g 2-18Roadsi de Turnouts, Dri veways andRoadsi de Control s- - - - - - - - - - - - - 2-3h 2-19Uti l i t i es---- ---- ---- ---- ---- ---- 2-3i 2-19Signs and Marki ng-- - - - - - - - - - - - - - 2-3j 2-19Li ghti ng-- -- -- -- -- -- -- -- -- -- -- -- - 2-3k 2-19


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EM1110-2-41031 Dec 82

Subj ectCross Secti on El emnts-- -- - - -- - - - - Paragraph2-4 Page2-20General -- -- -- -- -- -- -- -- -- -- -- -- - 2-4a 2-20Wdth-- -- -- -- -- -- -- -- -- -- -- -- -- 2-4b 2-20Curbs-- -- -- -- -- -- -- -- -- -- -- -- -- -- 2-4c 2-21Shoulders-- -- -- -- -- -- - -- -- -- - -- - 2-4d 2-22Sl opes, Drainage D tches,Channels and Erosi on Control - - 2-4e 2-23Gradi ng-- -- -- -- -- -- -- -- -- -- -- -- - 2-4f 2-25Obstructi on Cl earance--- - - - - - - - - 2-4g 2-25Crosswal ks-- -- -- - -- -- -- -- -- -- - -- - 2-4h 2-27Guardrai l s and Del i neators-- - - - - 2-4i 2-27I ntersecti on Desi gn El emnts-- ----- 2-5 2-29General -- -- -- -- -- -- -- -- -- -- -- -- - 2-5a 2-29Si ght Di stance-- -- -- -- -- -- -- -- -- 2-5b 2-29MnimmDesigns for SharpestTurns (Fi l l et Radi i ) ----------- 2-5c 2-29Speed Change Lanes-- -- --- -- -- -- -- 2-5d 2-30Traf f i c Control Devi ces---------- 2-5e 2-30Drainage Structures--- - - - - - - - - - - - - 2-6 2-32Hydraul i c Desi gn Frequency------- 2-6a 2-32Cul verts-- -- -- -- -- -- -- -- -- -- -- -- 2-6b 2-32Bri dges-- -- -- -- -- -- -- -- -- -- -- -- - 2-6c 2-32Improvi sed Structures--- - - - - - - - - 2-6d 2-32Drop Structures--- - -- - -- - -- -- - -- 2-6e 2-32Omssi on of Structures-- - - - - - - - - 2-6f 2-32Pavemnt Desi gn Consi derati ons-- -- 2-7 2-33Opti onal Desi gns- -- -- - -- -- - -- -- - 2-7a 2-33Use of Local Materi al s------- -- -- 2-7b 2-34Surface Course-- -- -- -- -- -- -- -- -- 2-7c 2-34Addi ti ve Stabi l i zati on--- - - - - - - - 2-7d 2-34Upgradi ng of Local Materi al s-- --- 2-7e 2-34Asphalt Eml si ons- -- -- - -- -- - -- -- 2-7f 2-34Pl asti c Soi l B nder-- -- -- -- -- -- - 2-7g 2-34Soi l Stabi l i zati on--- - -- - -- -- - -- 2-7h 2-35Pavemnt Desi gn for FrostCondi ti ons---- - -- - -- -- - -- - -- - - 2-7i 2-35Compacti on--- - - - - - - - - - - - - - - - - - - - 2-7j 2-35B anket Pavemnt Design---------- 2-7k 2-35Landscape Pl anti ng and Devel opmnt- 2-8 2-35General -- -- -- -- -- -- -- -- -- -- -- -- - 2-8a 2-35Sel ecti ve Thi nni ng and TreeProtecti on-- -- -- -- -- -- -- -- -- -- 2-8b 2-36

'l anti ng Desi gn-- - -- -- - -- -- - -- -- 2-8c 2-36Mscel l aneous Considerati ons------- 2-9 2-39Cl eari ng and Gubbi ng------- -- -- - 2-9a 2-39Top Soi l Stri ppi ng-- -- -- -- -- -- -- - 2-9b 2-39


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CHAPTER 3

CHAPTER4

EM 1110-2-41031 Dec 32

Subj ect Paragraph PageBorrowAreas-- -- -- -- -- -- -- -- -- -- - 2-9c 2-40Fi ni shi ng Rock Cuts and Fi l l s-- -- 2-9d 2-40Paymnt for Gradi ng--- -- -- -- - -- -- 2-9e 2-40Maintenance and Restorati on----- - 2-9f 2-40Pl anni ng and Design Techni ques-- - 2-9g 2-41

ROADSI DE FAC LITI ESAppl i cati on-- - - - - - - - - - - - - - - - - 3-1 3-1Control s-- -- -- -- -- -- -- -- -- -- -- -- -- - 3-2 3-1Desi gn Consi derati ons-------- ------ 3-3 3-1Overl ooks--- -- -- -- -- -- -- -- - -- -- -- 3-3a 3-1Vi stas--- --- --- --- --- --- --- --- --- 3-3b 3-3Turnout for Sani tary DumpStati on-- -- -- -- -- -- -- -- -- -- -- - 3-3c 3-6BOAT RAMPSI ntroducti on-- -- - -- -- -- - -- -- -- -- -- - 4-1 4-1Appl i cati on-- -- -- -- -- -- -- -- -- -- -- - 4-2 4-1Control s-- -- -- -- -- -- --- -- -- -- -- -- -- 4- 3 4-1Desi gn Considerat ions-- - - - - - - - - - -- - 4-4 4-1Characteri sti cs of Boat, Trai l erand Vehi cl e-- -- -- -- -- -- -- -- -- -- 4-4a 4-1Topography and PhysicalCondi ti ons--- -- - -- -- -- -- -- -- -- - 4-4b 4-2Soi l Stabi l i ty-- -- -- -- -- -- -- -- -- - 4-4c 4-2Geomtri c Desi gn-- -- -- -- -- -- -- -- -- - 4-5 4-2Access - - - - - - - - - - - - - - - - - - - - - - - - - - 4-5a 4-2Parki ng-- -- -- -- -- -- -- -- -- -- -- -- -- 4-5b 4-2Length and Wdth-- -- -- -- -- -- -- -- - 4-5c 4-3Shoul ders-- -- -- -- -- -- -- -- -- -- -- -- 4-5d 4-5Curbs-- -- -- -- -- -- -- -- -- -- -- -- -- -- 4-5e 4-7Surface-- -- -- -- -- -- -- -- -- -- -- -- -- 4-5f 4-7Drainage and Erosi on Control - - - - - - 4-6 4-7Markers and Si gns-- -- -- -- -- -- -- -- -- - 4-7 4-7Landscapi ng--- - - - - - - - - - -- - - - - - - - - -- - 4-8 4-7Li ghti ng-- -- --- -- -- -- -- --- -- -- -- --- - 4-9 4-8Temporary Ramps--- -- -- -- -- -- -- -- -- -- 4-10 4-8Ramps for Exi sti ng Impoundmnts--- -- 4-11 4-8Pl ank Ramps--- -- -- - -- -- -- -- -- -- -- -- - 4-12 4-8Mechani cal Boat Launchi ng Devi ces--- 4-13 4-10Loadi ng Pi ers--- --- --- --- -- --- --- --- 4-14 4-10Access to Water Far Non-Trai l eredBoats-- -- -- -- -- -- -- -- -- -- -- -- -- -- - 4-15 4-11


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EM 1110-2-41031 Dec 82

CHAPTER 5

CHAPTER 6

Subj ect Paragraph PageWALKS, STEPS, AND RAMPS

Appl i cabi l i ty-- -- -- -- -- -- -- -- -- -- -- -- - 5-1 5-1Control s-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 5-2 5-1Functi on-- -- -- -- -- -- -- -- -- -- -- -- -- -- 5-2a 5-1C imate-- --- --- --- --- --- -- --- --- --- - 5-2b 5-1Preservati on of Envi ronmntalVal ues-- -- -- -- -- -- -- -- -- -- -- -- -- -- 5-2c 5-1Topography and Physi cal Features-- - - 5-2d 5-1Constructabi l i ty and Mai ntai n-abi l i ty--- --- --- --- --- --- --- --- --- 5-2e 5-1Safety-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 5-2f 5-2Physical l y Handi capped--- -- -- -- -- - -- -- 5-3 5-2Desi gn Consi derati ons--- -- -- -- -- - -- -- - 5-4 5-2Wal ks-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- - 5-4a 5-2Steps--- --- --- --- --- --- --- --- --- --- - 5-4b 5-5Ramps-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- - 5-4c 5-5

TRAI LSFoot Trai l ---- ---- ---- ---- ---- ---- --- 6-1 6-1Appl i cati on-- -- -- -- -- -- -- -- -- -- -- -- - 6-l a 6-1Control s-- -- -- -- -- -- -- -- -- -- -- -- -- -- 6-l b 6-1Desi gn Consi derati ons-- - - - - - - - - - - - - 6-l c 6-1B ke Trai l s---- ---- ---- ---- ---- ---- --- 6-2 6-8Appl i cati on-- -- -- -- -- -- -- -- -- -- -- -- 6-2a 6-8Control s-- -- -- -- -- -- -- -- -- -- -- -- -- -- 6-2b 6-8Desi gn Consi derati ons-- -- -- -- -- -- -- - 6-2c 6-8R di ng Trai l s---- ---- ---- ---- ---- ---- - 6-3 6-12Appl i cati on-- -- -- -- -- -- -- -- -- -- -- -- 6-3a 6-12Control s-- -- -- -- -- -- -- -- -- -- -- -- -- -- 6-3b 6-12Desi gn Consi derati ons-- - - - - - - - - - - - - 6-3c 6-12Of-Road Vehi cles(ORV)- -- -- -- -- -- -- - 6-4 6-13Appl i cati on-- -- -- -- -- -- -- -- -- -- -- - 6-4a 6-13Control s-- -- -- -- -- -- -- -- -- -- -- -- -- 6-4b 6-14Desi gn Consi derati ons-- -- -- -- -- -- - 6-4c 6-14Physi cal Fi tness Trai l s-- -- -- -- -- -- - 6-5 6-16Appl i cati on-- -- -- -- -- -- -- -- -- -- -- - 6-5a 6-16Control s-- -- -- -- -- -- -- -- -- -- -- -- -- 6-5b 6-16Desi gn Consi derati ons-- -- -- -- -- -- - 6-5c 6-16Cross-Country Ski Trai l s-- -- -- -- -- -- 6-6 6-17Appl i cati on-- -- -- -- -- -- -- -- -- -- -- - 6-6a 6-17Control s-- -- -- -- -- -- -- -- -- -- -- -- -- 6-6b 6-18Desi gn Consi derati ons-- -- -- -- -- -- - 6-6c 6-18


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CHAPTER 7

CHAPTER 8

EM1110-2-410

Subj ect31

ParagraphDec 82PagePARKING

I ntroducti on-- -- -- -- -- -- -- -- -- - -- -- - 7-1 7-1Locati on-- -- -- -- -- -- -- -- -- -- -- -- -- -- 7-2 7-1Functi on-- -- -- -- -- -- -- -- -- -- -- -- -- 7-2a 7-1Terrai n--- --- --- --- --- --- --- --- --- 7-2b 7-1Layout-- -- -- -- -- -- -- -- -- -- -- -- -- -- - 7-3 7-2On-Road Parki ng-- -- -- -- -- -- -- -- -- - 7-3a 7-2Of-Road Parki ng-- -- -- -- -- -- -- -- -- 7-3b 7-3Termnal Parki ng-- -- -- -- -- -- -- -- -- - 7-3c 7-6Detai l s--- --- --- --- --- --- --- --- --- - 7-4 7-8Entrances and Exi sts-- -- -- -- -- -- -- 7-4a 7-8Motorcycl e and Bi cycl e -- -- -- -- -- - 7-4b 7-8Surfaci ng-- -- -- -- -- -- -- -- -- -- -- -- 7-4c 7-8Curbi ng-- -- -- -- -- -- -- -- -- -- -- -- -- - 7-4d 7-8Trees-- -- -- -- -- -- -- -- -- -- -- -- -- -- 7-4e 7-8Traff i c Channel i zati on I sl ands---- 7-4f 7-8PARK ENTRANCEAppl i cati on-- -- -- -- -- -- -- -- -- -- -- -- -- - 8-1 8-1Control s-- -- -- -- -- -- -- -- -- -- -- -- -- -- - 8-2 8-1Desi gn Consi derati ons------- -- -- -- -- - - 8-3 8-1Locati on-- -- -- -- -- -- -- -- -- -- -- -- -- -- 8-3a 8-1Park Entrace Area-- -- -- -- -- -- -- -- -- - 8-3b 8-1Entrance C osures-- -- -- -- -- -- -- -- -- - 8-3c 8-1Si gns--- --- -- --- --- --- --- --- --- --- -- 8-3d 8-2Approach Road------- - - - - - - - -- - - - - - - - 8-3e 8-2


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EM 1110-2-41031 Dec 82

LI ST OF TABLESNumber Ti tl e Page2-1 Suggested Design Speeds - Access Roads Outsi de Park------ ----- 2-52-2 Suggested Desi gn Speeds - Short Access Roads Outsi de Park--- - - 2-62-3 Suggested Desi gn Speed - C rcul ati on Roads-- -- -- -- -- -- -- -- -- -- 2-62-4 MnimumSi ght D stances i n Feet---- --- --- --- --- --- --- --- --- --- 2-72-5 MaximumDegree of Curve and MnimumRadi us for D fferentVal ues of MaximumSuperel evati on-- ------ ------- ------ ------- 2-122-6 MnimumLength for Superelevati on Runof f for 2-Lane Pavemnts- 2-132-7 MaximumGrades--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- 2-162-8 MnimumSurface Wdth - Two Lane Access Roads------- ------- --- 2-212-9 Normal Pavemnt Cross Sl opes--- --- --- --- --- --- --- --- --- --- --- - 2-212-10 Shoul der Cross Sl opes--- --- --- --- --- --- --- --- --- --- --- --- --- -- 2-242-11 MnimumHori zontal Obstructi on C earance-- -- -- -- -- -- -- -- -- -- -- 2-272-12 MnimumEdge of Pavemnt Designs for Turns at I ntersecti ons--- 2-316-1 Stoppi ng Sight D stances for Downhi l l Gradi ents-- ------ ------- 6-106-2 Desi gn Radi i ----- ----- ------ ------ ------ ------ ----- ----- ----- - 6-10


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LI ST OF FIGURESNumber Ti tl e Page2-1 Schemati c of typi cal recreati on road pattern showngthree mai n types of roads serving a recreati on si te------ -- - 2-22-2 MnimumStopping Si ght Dstance for Wet Pavement-------------- 2-82-3 Curving al ignment for recreati on roads---- ---------- -------- -- 2-92-4 Mnimumdesi rable radi i for recreati on roads--- -- -- -- -- -- -- -- - 2-142-5 Verti cal al i gnment of roads---- -------- ---------- -------- ----- 2-152-6 Special provi sion for drainage-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 2-182-7 Cross secti on el ements for recreati on roads---- -- -- -- -- -- -- -- - 2-202-8 Cross secti on showng pavement stri pi ng,

shoul der and guardrai l --- --- --- --- --- --- --- --- --- --- --- --- -- 2-242-9 Gradi ng for recreati on roads in acti vi ty areas-- -- -- -- -- -- -- -- 2-262-10 Bridge design for park areas--- --- --- --- --- --- --- --- --- --- --- - 2-332-11 Preservati on of l andscape features---------------------------- 2-373-1 V sta clearing---- ----- ---- ----- ---- ---- ----- ---- ----- ---- ---- 3-53-2 Parki ng for vi stas---- ----- ---- ----- ---- ---- ----- ---- ----- ---- 3-63-3 Mnimumdump stati on access drive--- --- --- --- --- --- --- --- --- -- 3-74-1 Access, ci rcul ati on and parking at a boat ramp---------------- 4-34-2 Access, ci rculati on and parki ng at a boat ramp---------------- 4-44-3 Rock protecti on detai l s for boat ramp

wthout curbs---- ---- ----- ---- ---- ----- ---- ----- ---- ----- --- 4-64-4 Rock protecti on detai l s for boat ramp

wth curbs---- ---- ---- ---- ----- ---- ----- ---- ---- ----- ---- --- 4-64-5 Concrete surface f i ni sh for boat l aunchi ng ramp--------------- 4-84-6 Boat ramp desi gn for wet placement--- -- -- -- --- -- -- -- -- --- -- -- - 4-94-7 Fixed l oading pi er i ntegral wth boat ramp--- -- -- -- -- -- -- -- --- 4-104-8 Dock faci l i ty for the handicapped park user--- -- -- -- -- -- -- ---- 4-115-1 Walk adj cent to parking area---- -- -- -- -- -- ---- -- -- -- -- -- -- -- -- 5-35-2 Access ramp to vi si tor center---- --- --- --- --- --- --- --- --- --- -- 5-56-1 Sceni c trai l wth paved surface---- -- -- -- -- -- -- -- -- -- -- -- -- -- - 6-26-2 Sceni c trai l wth unpaved surface--- -- -- -- -- -- -- -- --- -- -- -- -- - 6-36-3 Water bars---- ---- ----- ---- ----- ---- ---- ----- ---- ----- ---- ---- 6-46-4 Methods of providing guidance to the bl i nd--- --- --- --- --- --- -- 6-76-5 B cycle trai l -------------------------------------------- ----- 6-86-6 Mul ti -purpose trai l ------------ ------------- ------------- ---- 6-106-7 Of-road recreati on vehi cle trai l ---- ---- ---- --- ---- ---- ---- -- 6-146-8 Physical f i tness trai l ------------- ------------- -------------- 6-177-1 90-Degree parking--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- 7-27-2 60-Degree parking--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- 7-37-3 45-Degree parking--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- 7-47-4 Paral l el parki ng--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- - 7-57-5 Spur parking--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- -- 7-67-6 Pul l -off parki ng--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- - 7-77-7 Termnal parki ng--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- - 7-78-1 Typi cal entrance stati on to a recreati on si te----------------- 8-2

El f 1110-2-41031 Dec 82


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1-1 . Purpose . The purpose of thi s manual i s to present data compi l edfromexperi ence and research that may be useful to Corps of Engi neerspersonnel concerned wth desi gn of access and ci rcul ati on to recreat i onsi tes, areas and faci l i ti es . The materi al presented i n thi s manual i si ntended as desi gn gui dance f or obtai ni ng an end product whi ch resul ts i nsafe, useabl e, economcal recreati on devel opments and accessi bl e to al l .1-2. Appl i cabi l i ty . Thi s manual i s i ssued for the gui dance of Dvi si onand Dstri ct Engi neers havi ng responsi bi l i ty for the desi gn andconstructi on of recreat i on devel opments at Ci vi l Works proj ects .1-3. References .

a. TM5-818-2b . TM5-820-3c . TM5-820-4d TM5-822-2e . TM5-822-4f . TM5-822-5g TM5-822-6h . EM1110-2-1906

CHAPTER 1I NTRODUCTION

i . Ofi ce of the Chi ef of Engi neers, Standard Pavement J oi nt Curband Gutter - Vehi cul ar Rgi d, Standard Drawng No 40-17-02 dated 5 March1962 .

j . Ameri can Nati onal Standards I nsti tute (ANSI ) D 6 . 1-1978,"Manual on Uni formTraff i c Devi ces", U. S . Department of Transportat i on,Federal Hghway Admni strat i on, 1978.k . Archi tectural Graphi c Standards, 6th Edi t i on, The Ameri canI nst i tute of Archi tects, 1970.

EM1110-2-41031 Dec 82


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EM1110-2-41031 Dec 82

1 . The Amri can Associ ati on of State Hghway and Transportati onOf i ci al s (AASHTO, 341 Nati onal Press Bui l di ng, Washi ngton, D.C. 20004 :

1973 .

(1) A pol i cy on Geomtri c Desi gn of Rural Hghways, 1965 .(2) A pol i cy on Desi gn of Urban Hghways and Arteri al Streets,

1-4. Scope . Thi s manual presents basi c design consi derati ons for al lporti ons and modes of access and ci rcul ati on to and about recreati onareas and faci l i ti es . I t sets out speci f i c design considerati ons whi chwhen appl i ed can el imnate confusi on and dupl i cati on of design ef fort .An attempt i s made t o present the most ef f i ci ent, practi cal and ti mtested designs . Addi ti onal gui dance i s gi ven i n the formof constructi ondetai l s and by i l l ustrati ons of exi sti ng design sol uti ons . Thei l l ustrati ons were sel ected for thei r soundness and completeness formeti ng the publ i c need for recreati on faci l i ti es .1-5 . D scussi on Publ i c use and enj oymnt of recreati on resources atCorps proj ects depends upon many factors . Whether the vi si t i s byautomobi l e, boat, or on foot access and ci rcul ati on to and through parkand recreati on areas have a di sti ncti ve character and pl ay a maj or rol ei n i nf l uencing the recreati ng experi ence . The desi gn and l ocati on ofpark access and ci rcul ati on roads, parking areas, boat ramps, wal ks,steps, and trai l s must be in accordance wth the phi l osophy of howaperson vi ews the park and can be as signi f i cant as part i cipati on i n i tsacti vi ti es . Thi s phi l osophy of design ai ds i n i nsuri ng that Corpsproj ects becom pl aces to which peopl e go for a special ki nd ofexperi ence, rather than mrel y pl aces to get away f romeverydayacti vi ti es . Wthi n recreati on l ands, no road or other ci rcul ati on systemshoul d be desi gned onl y as a connecti ng devi ce to l i nk poi nts ofi nterest . Every segmnt of every recreati on access faci l i ty shoul drel ate to the envi ronmnt and the recreati on scene through which i tpasses i n a mani ngful way . Access and ci rcul ati on i n recreati on areasshoul d, to the extent possi bl e, consti tute an enj oyabl e and i nformati veexperi ence i n i tsel f . D rectness of route of recreati on roads shoul d notbe the overrul i ng factor i n sel ecti on of al i gnmnt . Thi s manual coversthe vari ous mans of access to recreati on si tes, areas and faci l i ti es .Special chapters cover road desi gn ; parking areas ; roadsi de faci l i ti es ;boat l aunchi ng ramps ; wal ks, steps and ramps ; trai l s ; and park entrances .


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2-1 . Appl i cati on . Recreati on roads are desi gned and bui l t primari l ysupport and provi de recreati on experi ences . A l arge percentage ofrecreati on vi si tors are si ghtseers and roads are primary recreati onfaci l i ti es f or them Nati onal pol i cy pl aces emphasi s on safety,aestheti cs, and accessabi l i ty to the physi cal l y handi capped i n desi gnpubl i c faci l i ti es . Road desi gners must be sensi ti ve to and routi nel yi ncorporate these features i n Corps desi gns . Desi gners shoul d befaml i ar wth and fol l ow the general road desi gn standards set out i nthi s manual . The road termnol ogy used i n thi s chapter i s that of theAmeri can Associ ati on of State Hghway and Transportati on Of i ci al s,AASHTO (formerl y AASHO) . Desi gn of a park road shoul d be accompl i shedan i nterdi sci pl i nary teamof professi onal s .2-2 . Control s .

a . Topography and Physi cal Features .

CHAPTER 2ROADS

General . Special knowedge and concern for protecti on of theresources and aestheti cs of the area through whi ch the access road passesand of the area where the recreati on faci l i ti es are to be developed areessenti al tool s of the recreati on road desi gner . A compl ete knowedge oftopography, physi cal features, and recreati on faci l i ti es i s requi red andthe best l ocati on for each has to be determned pri or to detai l ed desi gnof the access and ci rcul ati on road. I nformati on regardi ng topography,l and use and physi cal features, together wth traf f i c data form the maj ordesi gn control s . The other design control s di scussed bel ow dependl argel y on these control s . Si nce topography and l and use have such apronounced ef fect on road geometri cs, i nformati on regardi ng thesefeatures shoul d be obtai ned i n the earl y stages of pl anni ng and desi gn.Photogrammetry at the proper scal e and contour i nterval i s most hel pful .

(2) Types of Topography (Terrai n) . General topography types areestabl i shed here for cl assi fyi ng terrai n for common understandi ng i nthei r appl i cati on to desi gn needs . C assi f i cati on pertai ns to thegeneral character of the speci f i c route corri dor . C assi f i cati on i sestabl i shed here i n term of di f f i cul ty the design vehi cl e woul dencounter when a recreati on road i s pl aced on that terrai n Levelterrai n woul d not cause the design vehi cl e towng heavy l oads to reduceto speeds bel ow those of passenger cars on any secti on of the road . I ngeneral , rol l i ng terrai n causes vehi cles towng heavy l oads to reduce tospeeds bel ow those of passenger cars on some secti ons of road .

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t o

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Fi gure 2-1 Schemati c of typi cal recreati on road pattern showng threemai n types of roads servi ng a recreati on si te.Mountai nous terrai n may cause some vehi cles towng heavy l oads to operateat craw speeds . Def i ni ti ons of terrai n cl assi f i cati ons are as fol l ows :

(a) Level terrai n i s that condi ti on where si ght di stances aregeneral l y l ong or coul d be made to be so wthout maj or changes to thenatural envi ronment .(b) Rol l i ng terrai n i s that condi ti on where the natural sl opes

consi stentl y ri se above and fal l bel ow the roadway grade l i ne and whereoccasi onal steep sl opes of fer some restri cti ons to hori zontal andverti cal al i gnment .(c) Mountainous terrai n i s that condi ti on where l ongi tudi nal and

transverse changes i n the el evati on of the ground wth respect to theroadway are abrupt .b . Road C assi f i cati ons . Recreati on road cl assi f i cati ons are setout here for conveni ence of reference and to set the stage for good park


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road desi gn. The recreati on road i s di vi ded i nto three mj or types .These are : access road (the transi ti on between hi gh speed roads, and thepark area) ci rcul ati on road (an i ntegral part of the recreati on si te orarea), and the servi ce road (the l i nk between the hi gh speed, access, orci rcul ati on road and speci al servi ces provi ded by the park mnager andthe Government concessi onai re) . Fi gure 2-1 shows the di f ferent roadsservi ng a recreati on si te wth mst of the outdoor recreati on acti vi ti es .

(1) Access Road . An access road i s a road which permts vehi cles tomve between an exi sti ng publ i c thoroughfare and the recreati on si te orarea . These roads shoul d be envi ronmental l y pl easi ng to serve asapproaches t o recreati on areas . Access roads outsi de park boundari es mybe desi gned mre l i ke highways, whi l e access roads wthi n park boundari esshoul d be desi gned as recreati on roads . I n ei ther case the i mact on theenvi ronment shoul d be as sl i ght as feasibl e. Access roads my betwo-way, two- l ane roads and i n some i nstances di vi di ng of the l anes mghtbecome a practi cal appl i cati on.(2) C rcul ati on Road. A ci rcul ati on road i s a road whi ch connectswth an access road or other ci rcul ati on road and l eads to and throughrecreati on use areas and faci l i ti es . C rcul ati on roads my be two-way .(3) Servi ce Road . The servi ce road i s used pri mri l y formi ntenance and suppl y vehi cl es wthi n recreati on areas . Servi ce roadsmy al so serve as publ i c hi ki ng/bi ki ng trai l s and f i rebreaks . Norml l ythey wl l be one l ane wde . Turnarounds and passi ng l anes shoul d beprovi ded where needed or as requi red .c . Traf f i c .

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(1) I mortance of Traf f i c Data . The desi gn of a road or any partthereof shoul d be based upon factual data, amng whi ch are those rel ati ngto traff i c . Al l data shoul d be consi dered j oi ntl y . Cost, qual i ty offoundati ons, avai l abi l i ty of mteri al s, and other factors have i mortantbeari ng on the desi gn, but traf fi c i ndi cates the servi ce f or which theroad i s bei ng bui l t and di rectl y affects the geometri c features of desi gnsuch as wdth, al i gnment, grades, etc . Traf f i c i nformti on serves toestabl i sh the "l oads" for geometri c road desi gn.

(2) Desi gn Traf f i c . The quanti ty of traff i c for recreati on roadswl l be deri ved by anal yzing the road systemfor di stri buti on of traff i cgenerated by the park desi gn l oad . The desi gn l oad wl l be based onvi si tati on anti cipated on a norml weekend day duri ng the pri nci palrecreati on season wth ful l devel opment . The desi gn l oad (vehi cl esperday) wl l be used for each recreati on road cl assi f i cati on as outl i ned


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EM 1110-2-41031 Dec 82below i n the simlar way as Average Dai l y Traff i c count i s used i nhighway desi gn . Desi gn traff i c wl l not be based on the unusual l y heavytraff i c on a hol i day weekend such as the 4th of J ul y or Labor Day . I tshoul d be recogni zed that some congesti on and overl oadi ng wl l occur onhol i day weekends . The mx of vehi cl e types (rati o of SU:P-see paragraph2-2d (2)) shoul d al so be estimated for each road.

d . Vehi cl e Characteri sti cs .(1) Vehi cl e Characteri sti cs . The physi cal characteri sti cs ofvehi cl es i ncludi ng thei r si ze, maneuver patterns and the vari ous typesvehi cl es used by recreati oni sts are posi ti ve control s i n geometri cdesi gn . Some recreati on vehi cl es mght seemat a gl ance to have uni quecharacteri sti cs, i . e . , a 30-foot l ong motor home . The l ength, wdth,wheel base and turni ng radi us are al l siml ar to commerci al trucks orbuses . The motor home (RV) i s used extensi vel y for outdoor recreati on

experi ences and are used for extended vacati ons rather than the weekendrecreati on vi si t . These and other trends must be studi ed and veri f i edf romtime to time and perhaps for eachmaj or proj ect to be sure the ri ghtdesi gn data are sel ected .(2) Desi gn Vehi cl e. Thi s i s a sel ected motor vehi cl e, the wei ghtdimensi ons and operati ng characteri sti cs of whi ch are used to establ i shroad design control s to accommodate vehi cl es of a desi gnated type . Forpurposes of desi gn, the desi gn vehi cl e shoul d be one wth dimensi ons andmnimumturni ng radi us l arger than those of almost al l vehi cl es i n i tscl ass . The heavi est and l argest travel uni ts using recreati on roads areschool buses, motor homes and maintenance and constructi on ori entedvehi cles such as dump trucks . General l y, thei r l oaded weights wl l notexceed 10, 000 pounds (total wei ght) . A singl e uni t truck (SU), asdescri bed i n AASHTO"A Pol i cy on Geometri c Design of Rural Hghways",1965, best f i ts this class . (See Fi gure I I -9 of above referenced AASHTOPol i cy) . The SU Design Vehi cl e shoul d be used for access roads,ci rcul ati on roads, and servi ce roads whi ch wl l be used by buses, motorhomes and/or maintenance trucks . Oher roads whi ch wl l be used onl y bypassenger cars and l i ght pi ckup trucks may be designed based on Desi gnVehi cl e P (See Fi gure I I -3 of above referenced Pol i cy for defi ni ti on) .e . Capaci ty . Capaci ty wl l sel domgovern desi gn of recreati onroads . For two-way traff i c, two l anes of appropri ate wdth wl l almostalways accommodate traff i c for Corps parks . I n those rare i nstances

where two 12' wde l anes woul d be i nadequate, a proposal to provi de morethan two-l anes must be thoroughl y j usti fi ed i n a feature designmemorandumon the basi s of AASHTO capaci ty data and approved by theD vi si on Engi neer . One-way roads of more than one l ane wll al so requi rethe same j usti f i cati on and D vi si on Engi neer approval .

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f . Safety . I t i s imperati ve that the Corps' recreati on roads bedesi gned t o provi de safety to park part i ci pants . Thi s shoul d beaccompl i shed by appl yi ng the desi gn data set forth herei n wth soundprofessi onal j udgment to recreati on road needs .

g Cost . Road constructi on consumes a l arge percentage (25 percentand more) of funds avai l abl e for provi di ng recreati on faci l i ti es and al sofor proj ect maintenance . Consi derabl e desi gn effort i s necessary i ngetti ng the most road for the dol l ar i ni ti al l y, whi l e at the same timegi vi ng ful l consi derati on t o recreati on and envi ronmental val ues,maintenance, safety and l i f e cycle cost .2-3. Elements of Desi gn

a . Desi gn Speed . The desi gn speed of a roadway i s defi ned as "themaximumsafe speed that can be maintained over a speci f i ed secti on ofhi ghway when condi ti ons are so favorabl e that the desi gn features of thehi ghway govern" (AASHTO 1965) . Desi gn speed shoul d be sel ected wthrespect to the character of the terrai n and the l evel of roadway which i sto be constructed . Current desi gn standards are general l y based ondesi gn speeds rangi ng between 30 and 80 mles per hour . For recreati onalroadway system, however, 20 to 30 mle per hour desi gns shoul d beconsi dered far more sui tabl e and economc . The use of a reduced desi gnspeed may provi de for the reasonabl e reducti on of other desi gn parametersrel ated to the desi gn process, e. g . si ght di stances .(1) General . Tabl e 2-1 through 2-3 gi ve the desi gn speed for accessand ci rcul ati on roads as di scussed i n road cl assi f i cati ons set out i n

paragraph 2-2 .

Type ofTerrai n

Tabl e 2-1SUGGESTEDDESIGN SPEEDS (MPH)Access Roads Outsi de Park Boundari es Longer Than One Ml eConnecti ng a Publ i c Road*

Traff i c Brackets for Desi gn Control -Vehi cles Per Day (VPD0-50 50-250 250-400 400-750 750-1000 over 1000Level 40 40 50 50 50Rol l i ng 30 30 40 40 40Mountainous 20 20 20 30 30*Desi gn speeds for thi s type of access road shoul d adhere to thepri nci pl es of recreati on road desi gn rather than hi ghway desi gnstandards . Desi gn speeds shoul d be sel ected whi ch wl l begi n totransi ti on fromhi ghways t o recreati on roads . There i sdesi gn speeds greater than that whi ch wl l be permttedroad by l egal or regul atory speed l imts .

2-5

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504030

make theno need to useon thi s type of


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Reaches of Si gni f i cant Length Reaches through Developed Accessthrough Undevel oped Lands Areas and Si tes40 mph maximum 20 mph maxi mum

Reaches of Si gni f i cant Length Reaches through Devel oped Areasthrough Undevel oped Lands and Si tes30 mph maximum 20 mph or l ess

(2) Servi ce Roads . Use the maximumsuggested design speed thatterrai n permts economcal l y. The suggested range of design speeds i sf rom20 to 40 mph wth a maximumof 15 mph through developed si tes andareas .b Si ght D stance .

Tabl e 2-2SUGGESTED DESIGN SPEEDS (MPH)Short Access Roads Outsi de Park Boundari es andAccess Roads Wthi n Park Boundari es

Tabl e 2-3SUGGESTED DESIGN SPEED (MPH)C rcul ati on Roads

(1) Passi ng si ght di stance . Provi si on of the mnimumpassi ng si ghtdi stances i ndi cated i n Tabl e 2-4 i s secondary to fi tti ng the road to theterrai n, preservati on of natural resources, mnimzi ng earthwork andsafety of recreati on users scattered i n si tes and areas . The di stancestraversed by recreati on roads are rel ati vel y short and do not meri t muchef fort or cost to provi de safe passi ng sight di stances ; however, whenpassi ng i s not permtted, "No Passi ng" signs and marki ngs shoul d beprovi ded i n accordance wth Ameri can Nati onal Standards I nsti tute (ANSI )D6. 1-1978, "Manual on Uni formTraf f i c Control Devi ces-For Streets andH ghways" . Passi ng si ght di stance need not be provi ded on recreati onroads except that i t shoul d be at l east consi dered on l ong access roadsoutside parks .

(2) Stoppi ng si ght di stance . Mnimumsafe stoppi ng di stance foraccess roads shoul d be provi ded as i ndi cated i n Tabl e 2-4 Adj ustmentsmght have t o be made i n the case of ci rcul ati on roads where i ntegri ty ofsi te val ues (recreati on val ues) mght be compromsed. Posti ng of safespeeds mght be the designers choi ce i n these cases rememberi ng that


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(3) Measuri ng sightverti cal and hori zontal ,hei ght of eye, 3. 75 feetdistance, hei ght of eye,

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*NOTE : K val ue i s a coef f i ci ent by which the al gebrai c di f ference i n grademay bemul ti pl i ed to determne the l ength i n feet of the verti cal curvewhich wl l provi demnimumsight di stance.general l y speeds on ci rcul ati on roads are bel ow30 mph . Figure 2-2 showsdata for stoppi ng sight distances at i ntersecti ons for wet pavemnts wthi ncreases and decreases for percent grade . Professi onal j udgmnt shoul d beappl i ed i n muntai nous terrai n and terrai n between muntai nous and rol l i ngas to whether mnimumstoppi ng sight di stance shoul d be provided . Propersigni ngmght have to suf f i ce i n l i eu of extrem grading to attai nengi neeri ng i ntegri ty of the road desi gnThe need for si ght di stance across the i nsi de of hori zontal curves must notbe negl ected where there are si ght obstructi ons such as wal l s, cut sl opes,wooded areas, bui l di ngs, etc .

di stance . Cri teri a for masuri ng distance, bothare as fol l ows : for stoppi ng sight distance,and hei ght of obj ect 0. 5 foot ; for passi ng sight3. 75 feet and' height of obj ect, 4. 5 feet .

(4) Speci al appl i cati on of passi ng sight di stance . Passi ng sightdi stance i s not gi ven for desi gn speeds of 20 and 30 mh because where

MNMUMTabl e 2-4

SIGHT DISTANCES I N FEET

Desi gn Speed, mh 20 30 40 50Stoppi ng si ght di stanceMnimumStoppi ng SightD stance, feet 150 200 275 350K Val ue for : *Crest verti cal curve 16 28 56 . 85Sag verti cal curve 24 35 55 75Desirabl e Stoppi ng Si ghtD stance, feet 150 200 300 450K Val ue for : *Crest verti cal curve 16 28 65 145Sag verti cal curve 24 35 60 100Passi ng sight di stance :Passi ng distance, feet2-l ane - - - - 1500 1800K Val ue for : *Crest verti cal curve - - 686 985


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EM 1110-2-41031 Dec 82factors i ndi cate that speed that slow i s requi red on recreati on roads,passi ng i s undesi rabl e and desi gn data i s not needed . Roads designed for 20and 30 mph are ci rcul ati on roads i nside devel oped areas wth acti vi tyfaci l i ti es nearby, i . e . pi cni cki ng and camping.( 5) Speci al appl i cati on of mnimumsi ght di stance . Where crestverti cal curves and hori zontal curves occur at the same l ocati on i n rol l i ngterrai n, greater than mnimumsi ght di stance shoul d be used i n t he design t oassure that the hori zontal curve i s vi si bl e as dri vers approach . When thi scondi ti on occurs i n mountai nous terrai n proper si gni ng of safe speed andextent of hori zontal curve shoul d be used t o i ndi cate safe dri vi ngcondi ti ons and speed .c . Hori zontal A i gnment .(1) Desi gn phi l osophy . Long tangents shoul d not be used i n park road

desi gn . The hori zontal and verti cal al i gnment shoul d respect the terrai n,so that t he road i s l ai d l i ghtl y on the l and. I n deci di ng upon roadl ocati on, maximumemphasi s shoul d be gi ven t o i nterpreti ve and sceni cvalues . The desi gn and l ocati on of roads, trai l s, walks and overl ooksshoul d be i nterrel ated t o permt the vi si tors t o enj oy the park vi si t morethoroughl y w th as much freedomas possibl e i n the manuver of thei rautomobi l es, pedestri an travel and other form of park travel . Heavy

Fi gure 2-2 MnimumStoppi ng Si ght D stance for Wet Pavement

MnimumStoppi ngSi ght Dstancef or Wet Pavemnts

HghwayDesi gnSpeedAssumedSpeedFor Wet

MnimumStoppi ngSi ght D stance ForWet Pavement .Grades To2%Correcti on f or Stoppi ng Si ght D stance f or Wet Pavement

Condi t i on Decrease For Upgrade I ncr ease For DowngradeComputed Rounded +3% +6% +9% -3% -6% -9/0MP. H . MP . H . Feet Feet Feet Feet Feet Feet Feet Feet

30 28 176 200 10 20 10 20 3040 36 263 275 10 20 30 10 30 5050 44 369 350 20 30 20 5060 52 491 475 30 40 30 80


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earthworkshoul d berel i eved,el evati onprovi di ng cl ose-range vi ews of near scenes .constantl y changi ng vi ews of the scenery .(2) Layout . Curvi ng or wndi ng al i gnment i s preferred for recreati onroads . Park roads shoul d be al i gned wth curves, often compound, andconnected wth rel ati vel y short tangents or spi ral s, or both Fi gure 2-3shows curvi ng al i gnment for recreati on roads . I t i s desi rabl e to usetangents, curves and spi ral s t o def i ne the al i gnment of highways

Fi gure 2- 3 Curving A i gnment for Recreati on Roads

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i n cut and f i l l secti ons shoul d be avoided . I n effect the roadmol ded t o the terrai n through which i t i s passi ng Monotony i sand maximumadvantage i s taken of park val ues by changes i nand by devel opi ng viewpoi nts and overl ooks, as wel l as byCurvi ng al i gnment of fers


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EM 1110-2-41031 Dec 82wth appreci abl e traff i c ; however, for recreati on roads wth l ow traff i c,the al i gnment can be (a) "eyebal l ed" or (b) dri ven i n wth a passengervehi cl e or l i ght pi ckup truck . When ei ther method (a) or (b) i s used fordetermni ng al i gnment, i t shoul d be staked and referenced (and/or wtnessstaked) i n the fi el d wth appropri ate notati on provided on the pl ans andas-bui l t drawngs . The al i gnment for such mnor roads can be sketched onthe pl ans and the measured l ength shown for bi ddi ng and payment .Def l ecti on angl es at poi nts of i ntersecti on of up to fi ve degrees may beused wthout hori zontal curves i nside parks . Recreati on roads shoul d beal i gned to best accommodate the design of supporti ng faci l i ti es such asboat l aunchi ng ramps, camping faci l i ti es, pi cni c faci l i ti es, overl ooks,beaches, and thei r attendant parki ng faci l i ti es . Recreati on roads shoul dbe l ocated to preserve the i ntegri ty of the sceni c val ues of the proj ect,e . g . , reservoi r shorel i ne, bogs and natural rock outcroppi ngs .

(3) Roads i n reservoi r areas . General l y roads shoul d be l ocatedoutsi de areas that are l i kel y to be affected by shorel i ne erosi on Whensuch areas cannot reasonabl y be avoi ded, shorel i ne protecti on ( i . e . ,ri prap) shoul d be i ncl uded . Access roads to camping areas that can bef l ooded, part i cul arl y when rapi d pool ri ses can be expected, shoul d behi gh enough that they wl l provi de safe egress once the danger of ri si ngwater i s readi l y apparent .

(4) Maxi mumcurvature . Dependi ng on the maxi mumsuperel evati on val uesel ected by the desi gner, the maxi mumcurvature for di f ferent desi gnspeeds i s shown i n Tabl e 2-5.(5) Superelevati on. Where i ce and snoware factors, a superel evati onrate of about 0. 08 i s a l ogi cal maxi mumto mni mze sl i ppi ng across the

road when stopped or when attempti ng to start froma stopped posi ti onFromTabl e 2-5 above, i t can be seen that there i s l i t t le to be gai ned i ngreater permssi bl e maxi mumdegree of curve by i ncreasi ng the maxi mum"e"above 0. 08 . Greater rates of superel evati on tend to cause excessivei nward f ri cti on requi red to dri ve sl owy around the curve, a condi ti onresul ti ng i n errati c vehi cl e operati on For thi s reason, i t i srecommended that a maxi mumsuperel evati on rate of 0. 08 normal l y be used .Where l ow speed operati on wl l prevai l , a l owmaxi mumrate ofsuperel evati on i s appropri ate . For addi ti onal gui dance on standards forsuperelevati on, fol l ow the practi ce of the l ocal hi ghway department orAASHTO pol i cy for rural roads . The extent and nature of appl yi ngsuperel evati on i n recreati on road design shoul d be tempered wth theknowedge of the need for the road to be open duri ng extreme wntercondi ti ons and the actual posted speed i ntended. Roads i n camping areasare subj ect to not more than 15 mph posted speeds . Many other park areasneed to have 15 mph speeds posted. The need for superel evati on shoul d betempered wth thi s knowedge . Road desi gners need to become ful l yi nformed as to how the area served by the road wl l be managed .

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(6) Superel evati on runoff . Superel evati on runoff i s the l ength ofroadway needed to accompl i sh the change i n cross sl ope froma normal crownsecti on t o a ful l y superel evated secti on Mnimuml engths of runoff areshown i n Tabl e 2-6 . Adj ustments i n desi gn runoff l engths may be necessaryfor smooth ri di ng, surface drai nage, and good appearance . For l ow speedcenter-crowned roads, removal of the adverse crown i n the outsi de l ane toprovi de a "shed" transverse grade slopi ng to the i nside of the curve maybe adequate for the runoff requi red . On curves wth spi ral s thesuperel evati on runoff i s effected on the spi ral . On curves wthoutspi ral s, from60 to 80 percent of the l ength of runoff shoul d be l ocatedon the tangent . Smoothl y rounded edge of pavement profi l es are thedesi red end i n desi gn of superel evati on runoff, rather than exactness i nfi tting the above gui de val ues . For addi ti onal design detai l s, fol l ow thepracti ce of the l ocal hi ghway department or AASHTO pol i cy .

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(7) Mnimumdesi rabl e radi i . Figure 2-4 shows mnimumdesi rabl eradi i for very l ow speed (5-10 mph), l ow desi gn traff i c recreati on roadcurve.(8) Pavement wdeni ng on Curves . Pavement wdeni ng need not beprovided at hori zontal curves i n recreati on roads wth radi i to the i nsideedge of surface greater than 100 feet because of the l ocal nature

of the roads, reduced vehi cl e operati ng speeds, rel ati vel y l ow traff i cvol umes and the absence of l arge commerci al trucks . Because recreati onroads shoul d curve t o f i t the terrai n i t i s more desi rabl e i n rol l i ng tomountai nous rough terrai n fromthe standpoi nt of vehi cl e operati on,constructabi l i ty and appearance to make the normal road surface wdthabout two feet wder than the practi cabl e mnimumthan to wden fi rst onone side and then the other . I n l evel terrai n f l atter curves can beused. I t i s signi f i cant to note that the AASHTOmakes no recommendati onfor wdeni ng for l ocal roads . Wdeni ng shoul d onl y be provided i nrecreati on roads when i t i s crucial to safe vehi cl e operati on. A so, seeparagraphs 2-4b and 2-4d for extensi ve design data for pavement wdeni ngof recreati on roads . I n the unusual i nstances where wdeni ng on curvesmust be used, fol l ow the standard of the l ocal hi ghway department or thedesi gn pol i ci es of the AASHTO

(9) Design wthout superel evati on. Frequentl y i n parks wthconsi derabl e i rregul ari ty i n terrai n, the di stance between reverse curveswl l be too short to permt adequate runout of superel evati on for areversal i n the cross sl ope of the road surface. The use ofsuperel evati on i n extremel y curvi ng roads as opposed to normal centercrown cross secti ons adversel y affects constructabi l i ty and control ofgradi ng. Some park road desi gners prefer to desi gn ci rcul ati on andservi ce roads, where terrai n and soi l s permt, wth the cross sl ope


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Tabl e 2-5MAXIMUMDEGREE OF CURVE AND

MNMUMRADIUS FOR DI FFERENT VALUESOF MAXIMUM SUPERELEVATI ON

*Note : e = rate of roadway superel evati on, foot per foot .approximatel y paral l el to the natural cross sl ope of the exi sti ng ground(wthout roadsi de di tches) . I n no case shoul d the cross sl ope be l ess than- i nch per foot nor more than 2-i nch per foot . Omssi on of superelevati onmay be permtted provi ded that after roads have been constructed, butbefore they are opened to the publ i c, the maximumsafe speed fornegoti ati ng curves i s determned and posted wth si gns .

Desi gnSpeedMPH

Maxi mume*

MnimumRadi us(Rounded)Feet

Max. Degreeof Curve(Rounded)Degrees

20 . 06 115 50. 0 .30 . 06 275 21. 040 . 06 510 11 . 550 . 06 830 7. 020 . 08 110 53. 530 . 08 250 23. 040 . 08 460 13. 050 . 08 760 8. 020 . 10 100 58 . 030 . 10 230 25. 040 . 10 430 14. 050 . 10 690 9. 0

20 . 12 95 63. 030 . 12 215 27. 040 . 12 400 15. 050 . 12 640 9. 0


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El f 1110-2-+1031 Dec 82

MNMUMDESIRASLEFRADUSTURNAROUNDS

MNMUMOESIRASLESURFACEEDGERADUS

CRCULATONROADINTERSECTONSSnl d. prk. r w

Fi gure 2-4 MnimumDesi rabl e Radi i for Recreati on RoadsCURVEVVDENNO

bal anci ng cut and f i l l wthi n economcal haul di stance . Recreati on roadsare di f ferent . For a traf f i c way that bl ends and f l ows wth the terrai nas wel l as provi des a smoth transi ti on f romthe paving to the roadsi defor errant vehi cl es, the verti cal al i gnmnt shoul d fol l ow the exi sti nggrade as cl osel y as possi bl e . When sui tabl e borrowmateri al i seconomcal l y avai l abl e, consi derati on shoul d be gi ven to bui l di ng theroadbed sl i ghtl y above natural ground rather than tryi ng t o bal ance cutand f i l l . Oten thi s wl l provi de better drai nage, create l essdi sturbance of the envi ronmnt, be l ess costl y, and create l ess probl emfroman erosion control standpoi nt . A l borrowareas used i n thi s mannershoul d be l ocated to provi de the l east di sturbance to the envi ronmnt,preferabl y out of the vi ewof vi si tors . When economcal l y feasibl e,borrowshoul d be taken belowthe el evati on of a conservati on or permanentpool . Inmuntai nous terrai n i t may be necessary to exceed the desi rabl emaximumgrades because the cost of doi ng otherwse would be prohi bi ti veand the envi ronmnt severel y harmd. When i t i s necessary to exceed thedesi rabl e maximumgrades, the reaches shoul d be kept as short as feasi bl eand combi nati ons of steep grade and hori zontal curves shoul d be avoided,as much as possi bl e . Consi derati on shoul d be gi ven to the dangers thatsteep grades pose when traversed by l i ght vehi cl es towng trai l ers .


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Steep grades are parti cul arl y undesi rabl e for gravel -surfaced roadsbecause they are unsafe when wet and the gravel tends to be washed away .Fi gure 2-5 i l l ustrates good verti cal al i gnment of roads i n park areas .

Fi gure 2- 5 Verti cal A i gnment of Roads

EM 1110-2-41031 Dec 82


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EM 1110-2-41031 Dec 82

(2) Maximumgrades . Tabl e 2-7 shows the desi rabl e maximumgradesfor di f f erent types of terrai n and design speeds i n percent .

*Note : For roads wth desi gn traf fi c below 250 or where terrai n i s suchthat the grades shown woul d requi re cut and/or f i l l that woul d beexcessive for a park road, grades of rel ati vel y short l engths may bei ncreased up to 150 percent of the val ues shown whi l e observi ng thecauti ons i n paragraph 2-3d(1) above .

(3) Verti cal curves . Vert i cal curves are used to ef fect gradualchange between tangent grades . They shoul d be simpl e i n appl i cati on andshoul d resul t i n a design whi ch i s safe, comortabl e i n operati on,pl easing i n appearance, and adequate for drai nage . The maj or control forsafe operati on on crest vert i cal curves i s the provi si on of mnimumstoppi ng sight di stances for the desi gn speed. I n any desi gn the si ghtdi stances shoul d be consi stent wth the terrai n and conservati on of theenvi ronmnt . Consi derati ons of comort requi re that vehi cul ar rate ofchange of grade be kept wthi n tol erabl e l imts . Thi s i s most importanti n sag verti cal curves where gravi tati onal and vert i cal centri fugalf orces act i n the sam di rect i on Appearance al so shoul d be consi deredA l ong curve has a mre pl easi ng appearance than a short one whi ch maygi ve the appearance of a sudden "break" i n the prof i l e due to the ef fectof foreshorteni ng . Simpl e parabol i c curves shoul d be used on recreati onroads . Verti cal curve data i ncludi ng K val ues are gi ven i n Tabl e 2-4under paragraph 2-3b(2) above, enti tl ed MnimumSi ght D stances i n Feet .I n recreati on road desi gn, mnimumsi ght di stances mght be therul e i nstead of the excepti on and provi si on of prescri bed appropri atemarki ngs and si gns i n accordance wth ANSI D6. 1-1978 can provi de theproper safety precauti ons .

(4) Grades at i ntersecti ons . Where i ntersecti ons occur on roadsecti ons wth moderatel y steep grades, i t i s desi rabl e to reduce thegradi ent through the i ntersecti on i n al l l egs of the i ntersecti on. Sucha prof i l e change i s benef i ci al for al l vehi cl es maki ng turns and reducespotenti al hazards .

2-16

Tabl e 2-7MAXIMUMGRADES*

Type of Terrai n Desi gn Speed MPH20 30 40 50Fl at 7 7 7 6Rol l i ng 10 9 8 7Mountainous 12 10 10 9


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"COMBINATIONOF HORIZONTAL ANDVERTICAL ALI NEMENT"

EM 1110-2-410

"Hori zontal and verti cal al i nement shoul d not be desi gnedi ndependentl y . They compl ement each other, and poorl y desi gnedcombinati ons can spoi l the good poi nts and aggravate the defi cienci es ofeach Hori zontal al i nement and profi l e are among the more important ofthe permanent desi gn el ements of the highway, f or whi ch thorough study i swarranted. Excel l ence i n thei r desi gn and i n the desi gn of thei rcombi nati on i ncrease uti l i ty and safety, encourage uni formspeed, andimprove appearance, almost always wthout addi ti onal cost ."ALI NEMENT COORDNATION IN DESIGN"

31 Dec 82e . Combinati on of Hori zontal and Verti cal A i gnment . Desi gn of arecreati on road i s an art i n three dimensi ons embodyi ngmany control s andelements, al l i nterrel ated . The fol l owng are excerpts fromthe AASHTO"A Pol i cy on Geometri c Desi gn of Rural Hghways", 1965 and are appl i cabl eto recreati on road desi gn, but wth more emphasi s on envi ronmental val ues

and l ess emphasi s on eff i ci ency i n movi ng traff i c rapi dl y .

"Coordi nati on of hori zontal al i nement and prof i l e shoul d not be l eftto chance but shoul d begi n wth prel imnary desi gn, duri ng whi ch stageadj ustments can be readi l y made . Whi l e a speci f i c order of study for al lhighways cannot be stated, a general procedure appl i cabl e to mostfaci l i ti es can be outl i ned .

"The designer shoul d uti l i ze worki ng drawngs of a size, scal e, andarrangement so that he can study l ong, conti nuous stretches of highway i nboth pl an and prof i l e and vi sual i ze the whol e i n three dimensi on.Worki ng drawngs shoul d be of suff i ci entl y smal l scal e, general l y 1 i n. _100 f t . or 1 i n =200 ft . , wth the prof i l e pl otted j oi ntl y wth thepl an A conti nuous rol l of pl an-profi l e paper usual l y i s sui tabl e forthi s purpose .

"After study of the hori zontal al i nement and prof i l e i n prel imnaryform adj ustments i n each, or both, can be made j oi ntl y to obtai n thedesi red coordi nati on. At thi s stage the desi gner shoul d not be concernedwth l i ne cal cul ati ons, other than knownmaj or control s . The studyshoul d be made l argel y on the basi s of a graphi cal anal ysi s . I n doi ng sothe use of spl i nes, highway curve templ ates, shi p curves, andstrai ghtedges are conveni ent i n proj ecti ng both the hori zontal al i nementand the grade l i ne. The cri teri a and elements of design covered i n thi sand the precedi ng chapter shoul d be kept i n mnd . For the sel ecteddesi gn speed the val ues for control l i ng curvature, gradient, si ghtdi stance, superel evati on runoff l ength, etc . , shoul d be avai l abl e andchecked graphi cal l y . Desi gn speed may have to be adj usted duri ng theprocess al ong some secti ons to conformto l i kel y vari ati ons i n speeds ofoperati on where noti ceabl e changes i n al i nement characteri sti cs mayoccur . A l aspects of terrai n, traff i c operati on, and appearance can beconsi dered and the hori zontal and verti cal l i nes adj usted and coordinatedbefore the costl y and time consumng cal cul ati ons and the preparati on ofconstructi on pl ans to l arge scal e are started .

2- 1 7


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EM1110-2-41031 Dec 82

"The coordi nati on of hori zontal al i nement and prof i l e f romthevi ewpoint of appearance can be accompl i shed vi sual l y on the prel imnaryworking drawngs . General l y thi s resul ts i n a sati sfactory product whendone by an experi enced desi gner . Thi s means of anal ysi s may besupplemented by model s of perspecti ve sketches at l ocati ons where theeffect of certai n combinati ons of l i ne and grade are questi onabl e. "

f . Drainage and Erosi on Control . The i mportance of good drainage,both surface and subsurface cannot be overemphasi zed. Inadequatedrai nage, erosion control and overl oadi ng are the three greatest causesof road fai l ures . Some general gui dance for the desi gn of drai nage anderosion control desi gn i s gi ven i n the fol l owng sub-paragraphs .(1) Desi gn drainage structures to bl end i nto the surroundi ngl andscape rather than i ntrude upon i t . A so use drai nage grates thatwl l not di vert bi cycl e wheel s when passed over . See Fi gure 2-6 .(2) Avoi d l ong di tches al ong roadways whi ch tend to accumulate

l arge f l ows and requi re bi g di tch secti ons . The use of subdrai ns, catchbasi ns, water bars, drainage di ps, f ree drai ni ng embankment sl opeprotecti on, sl ope seedi ng and outsl opi ng road surfaci ng shoul d beconsi dered i n the desi gn.(3) To the extent feasibl e, use natural materi al s such as stone forvel oci ty and erosi on control to avoi d the hi gh vel oci ti es of concretechute structures . More speci f i c gui dance on roadway di tch desi gn i spresented i n paragraph 2-4e and on drai nage structure desi gn i n paragraph2-6 .g Landscape Development . Landscapi ng shoul d be used for

aestheti cs, erosion control and to ai d safety of dri vers andpedestri ans . Landscapi ng of recreati on roads can be accompl i shed byvegetati on, by shapi ng l and form, and by l ocati on of the road i tsel f .Landscape devel opment shoul d be an el ement of the recreati on road desi gn

Fi gure 2-6 Speci al Provi si on for Drainage2-18


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E1k1 1110-2-410~1 Dec 32

h . Roadsi de Turnouts, Dri veways and Roadsi de Control s . Thesefuncti onal elements need to be consi dered i n the desi gn of recreati onroads . Thei r frequency, l ocati on i n rel ati on to sceni c features andrecreati on faci l i ti es, where they occur i n rel ati on t o traff i c volum andthe safety of the user, and howwel l they serve the recreati oni st forenj oyment i n the park vi si t are al l important consi derati ons i n roadsi decontrol . The eff i ci ency and safety of a recreati on road depend greatl yupon the amount and character of roadside i nterference most of whichori gi nates i n recreati on vehi cl e movements to and fromthe park and areaswthi n the park . Overl ooks and vi stas, i ntersecti ng roads l eadi ng up tospeci f i c acti vi ty areas, off -road parki ng access, the camping spur, f eecol l ecti on and check-i n stati ons are exampl es of the roadside functi onalelements to be consi dered

i . Uti l i ti es . Uti l i ti es such as power l i nes, tel ephone, water, gasand sewerage mains, which occupy or cross the road ri ght-of - way, shoul dbe considered i n l ocati on and desi gn of the road. Normal l y, on newconstructi on, no uti l i ty shoul d be si tuated under any part of thepavement, except where i t must cross the road. For such cases theuti l i ty shoul d be pl aced i n a pi pe sl eeve. Preferabl y undergrounduti l i ti es shoul d be l ocated outside the roadway to avoi d any di sturbanceto traff i c duri ng uti l i ty mai ntenance acti vi ti es .

j . Si gns and Marki ngs . Si gns and marki ngs are di rectl y rel ated tothe desi gn of the road and are features of traff i c control and operati onwhi ch the designer must consider i n geometri c l ayout of the work . Si gnson proj ect l ands shoul d be i n accordance wth EP 310-1-6, Chapter 4,Signage Si gns not on proj ect l ands shoul d be coordi nated wth theappropri ate state, county, or l ocal authori ty . I n addi ti on signs,marki ngs, and other traff i c control devi ces pertai ni ng to recreati onroads shoul d be provided i n accordance wth the Manual on Uni formTraff i cControl Devi ces for Streets and Hghways, ANSI D6.1-1978, U. S . Departmentof Transportati on, Federal Hghway Admni strati on . Si gns requi red toproperl y di rect and warn dri vers shoul d be provided for publ i c safety.

and

k . Li ghti ng Normal l y, l i ghti ng wl l not be provided except toimprove safety at parti cul ar hazards or for securi ty reasons . Hazardswhich woul d requi re l i ghti ng shoul d be avoi ded to the extent possi bl e byprudent road desi gn and recreati on faci l i ty management techni ques andpracti ces . Lowni ghttime traff i c vol umes general l y prevai l i ng i n parksand l ow speed operati on imposed i n developed si tes and areas shoul dusual l y obvi ate the need for l i ghti ng of roads . When l i ghti ng i snecessary, l umnari es shoul d be pl aced on standards hi gh enough tomnimze the effect of gl are and to prevent vandal i sm Standards shoul dbe l ocated back of the hori zontal obstructi on clearance . Li ghti ng i n

2- 1 9

Center l i ne marki ngs, no passi ng markings and pedestri an and cycl ecrossing marki ngs are al so stressed. Al so see di scussion on signi ngmarki ng as geometri c desi gn el ements i n AASHTO "A Pol i cy on Geometri cDesi gn of Rural Hghways", 1965 for addi ti onal gui dance .


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EM1110-2-41031 Dec 82developed areas for roads shoul d be coordi nated wth any other l i ghti ng,such as for campgrounds . Break-away standards shoul d be used al ongroadways . For addi ti onal di scussi on of l i ghti ng, see AASHTOpol i cy .2-4 . Cross Secti on El emnts .

a . General . The desi gn el emnts covered i n thi s paragraph arei l l ustrated on Figure 2-7 and the term used conformwth those on thei l l ustrati on . The desi rabl e range of rate of normal cross slopes i sgi ven i n Tabl e 2-9.b . Wdth.(1) Access roads . The mnimumsurface wdths shoul d be as gi ven i nTabl e 2-8 . The wdths gi ven i n the tabl e have been adj usted f romnormaldesi gns . These adj ustmnts are made for the fol l owng reasons . Fi rst,the surfaced l anes of recreati on roads are i ncreased to provi de a greatermargin of safety and to reduce maintenance of the pavemnt edge and/orthe shoul der at the pavemnt edge . Thi s wdeni ng hel ps di stracteddri vers to maintain control of the many types of recreati on vehi cl esespeci al l y those pul l i ng trai l ers . Second, the park area can beconsi dered a desti nati on poi nt and dri vers need a wder pavemnt for safeoperati on of vehi cl es under congested condi ti ons . Thi rd, i t i s importanti n the i nterest of safety to paint a whi te str i pe al ong the very edge of

the pavemnt or one to two feet i nside f romthat edge dependi ng on theamount of pavemnt wdeni ng . See Figure 2-8.

Figure 2-7 Cross Secti on el emnts for recreati on roads2-20


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(2) C rcul ati on Roads .

Tabl e 2-8

EM 1110- 2- ! 41031 Dec 82

(a) Two-way ci rcul ati on roads . Surface wdth should normal l . v be22-feet . Roads wth desi gn traffi c of over 250 VPD and when desi gnvehi cl e SU i s used, surface wdth may be 24-feet wde . Where desi gnvehi cl e P i s appl i cabl e and desi gn traff i c i s l ess than 250 VPD 18-footwde surface may be used . Mnor short ci rcul ati on roads and loops mayal so have 18-foot wde surface . When i n doubt, use 20-foot surface .(b) One-way ci rcul ati on roads . _ Surface wdth should be 12-feetexcept for l ong roads wth very sharp curves, through l arge campgrounds,where wdth should be 14-feet wde .(3) Servi ce roads . - When surfaced, the surface wdth shoul d be 10

feet . The type of surfaci ng provi ded shoul d meet the need of access tothe servi ce faci l i ty ( i ncl udi ng O&M requi rements) . Surfacing of servi ceroads mght be economcal for short di stances to aid erosion control andother drai nage problems .

MNMUMSURFACE WDTH - TWO LANE ACCESS ROADS

Tabl e 2-9NORMAL PAVEMENT CROSS SLOPES

c . Curbs . There are fewappl i cati ons of curbs i n desi gn andconstructi on of recreati on roads . They should be used onl y when neededfor one or more of the fol l owng purposes . (1) to control . drai nage, (2)

2-21

Desi gnSpeed,MPH

VPDLessThan50

Surface Wdth i n Feet(Vechi ctes per day)VPD

50-250

for Design

VPD250-400

Traff i c of :

VPD400-750

Over750VPDwth peaks20 22 22 24 24 2430 22 24 24 24 24

40 22 24 24 24 2650 22 24 24 24 26

Surface type Inch per footCross SlopesFoot per foot

Hgh 1/8-1/4 . 01- . 02I ntermedi ate 3/16-3/8 . 015- . 03Low 1/4-1 / 2 . 02- .04Unsurfaced 1/2-1 " 04- " 08


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EM 1110-2-41031 Dec 82to confi ne vehi cl es to the pavement, or (3) to di rect or channel i zetraff i c . When curbs are used they shoul d be desi gned i n accordance wthparagraph 3. 3. 3 . 3 of TM 5-822-2. I n addi ti on to the desi gns shown i n CEStandard Drawng No. 40-17-02 the fol l owng designs may al so be used :(1) extruded or sl i p-formed asphal ti c concrete or Portl and cement curb,(2) when di recti on of drainage i s away fromthe curb, a f ree standi ng,part i al l y buri ed more or l ess rectangul ar shaped wal l type concrete,masonry or rei nforced concrete curb wth the exposed traff i c sidesl i ghtl y battered away fromthe road surface, ( 3) pre-cast wheel stopsand (4) a l ow fl at, cast i n pl ace curb on grade, more or l ess rectangul ari n cross secti on wth i ts wdth at l east twce i t s height . Where abarri er onl y i s needed, l ogs, rai l road ti es, masonry wal l s or otherequi val ent materi al may be used so l ong as i t does not impose ani ncreased hazard to vehi cl es .

d . Shoul ders .(1) Access roads outside park boundari es Shoul ders on access roadsoutsi de park boundari es shoul d be desi gned to the standards of thehighway agency who wl l be responsi bl e for the operati on and mai ntenanceof the constructed roadway . A l other access roads (those i nside parkboundari es) shoul d be desi gned i n accordance wth the data gi ven below(2) Access roads and ci rcul ati on roads i nside park boundari es .Because of the purpose and nature of the recreati on road and the moodgenerated by the terrai n, shoul ders for those roads i nsi de parkboundari es serve modi f i ed purposes . The purpose of shoul ders for thi s

type of road i s needed to protect pavement edge and provi de transi ti onbetween the pavement and f i l l or cut sl opes . Temporary storage ofdi sabl ed vehi cles i s not important on the usual l y short l ength of road,because of the slow speed of traff i c, and the l ength of tim, both weeklyand dai l y the road i s i n use. D sabl ed vehi cl es can be tol erated betteri n recreati on areas, therefore, compl ete off -the-road temporary vehi cl estorage i s not cri ti cal . Preservati on of the natural resources becomesvery important i n recreati on areas and must be deal t wth whi l e desi gni ngpark roads .

(3) Importance and functi ons . Because recreati on areas attract manytypes of vehi cl es, i t seem prudent to reduce the usual road shoul der forrecreati on roads and i ncrease the pavement wdth accordi ng to the designspeed and extent of use . An addi ti onal characteri sti c of the recreati onroad, i . e . , curvi ng al i gnment, al so adds credence to the reducti on ofshoul der wdth and i ncreasing pavement wdth pri ncipl e . Pavementwdeni ng i s practi ced for the ordi nary highway at curves . Shoul ders onal l recreati on roads shoul d be stabi l i zed to provi de l ateral support forthe pavement, faci l i tate drai nage of the pavement (both surface andsubsurface), reduce mai ntenance cost, and provi de greater safety forvi si tors . See the di scussion on i mportance of stabi l i zi ng shoul dersbegi nni ng on page 238 of AASHTO "A Pol i cy on Geometri c Desi gn of RuralHghways, 1965 . The stabl i zati on need not be extended at ful l depth for

2- 2 2


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(4) Shoul der wdth

(b) Servi ce Roads . Surfaced roads shoul d have 1-1/2 feet wdeshoul ders .

EM 1110-2-41031 Dec 82

the enti re shoul der wdth A feathered edge cross sl ope may be used foral l or part of the shoul der wdth A shoul der materi al . that wl l providestabi l i zati on and support a stand of grass i s desi rabl e . Shoul derstabi l i zati on to provide traff i c support and support the growh ofvegetati on may requi re some addi ti onal cost but i t i s j usti f i ed i ncl i mates that wl l sustai n growh . The shoul der design shoul d provi desuff i ci ent depth t o al l ow root devel opment and t o sustai n thevegetati on . Pl acing a thi n l ayer of soi l over a steri l e base course onthe shoul der i s not desi rabl e for traff i c support or for sustai ni ngvegetati on . See the di scussion on turfed shoul ders on page 239 of theAASHTO pol i cy referred t o above . For traf f i cabi l i ty of shoul ders gi veappropri ate considerati on t o camping and boat trai l ers of consi derabl eweight on smal l wheels .

(a) Access roads and ci rcul ati on roads . Shoul ders for access andci rcul ati on roads for most recreati on areas shoul d be 2 feet . I n somecases a greater wdth mght be requi red for safety .

(c) Shoul der wth guard rai l . . Where a guard rai l i s used theshoul der shoul d be i ncreased 1 to 2 feet to permt setti ng the guard rai lfarther from the edge of the surface. Fi gure 2-8 shows a typi cal exampl eof good shoul der wdth wth a guardrai l on an access road

(5) Shoul der cross sl opes . The desi rabl e range of cross sl opes i sgi ven i n Tabl e 2-10 for types of shoul der surfaces .e . Sl opes, Drainage D tches, Channel s and Erosi on Control . Theseshoul d be desi gned for mnimumgradi ng and cleari ng, safe and pl easi ng

roadsi des, and to present the l east di ff i cul ty i n erosi on control . Seedi scussion of these desi gn el ements i n AASHTO pol i cy . There i s aconf l i ct between two desirabl e features for di tches and sl opes . Theseare :(1) Sl opes shoul d be rel ati vel y f l at and di tches shal l ow for safetyand t o bl end wth the terrai n.(2) The total wdth of the constructi on cross-secti on shoul d benarrow t o reduce cl eari ng and mni mze the scar caused by constructi on .

Thi s requi res j udgment to devel op a good overal l desi gn . I n cut secti onsi t i s recommended that the si desl opes be 6 : 1 ( 6 hori zontal on i verti cal )


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EM1110- 2-41031 Dec 82tends t o bl ock di tches, i mpedi ng runoff so as t o cause damagi ngsaturati on of t he pavement or subgrade; and (c) where deeper di tches wl lreduce overal l cost where freezi ng governs pavement desi gn thi ckness .Dtches shoul d be routed and sl opes warped where feasibl e t o savedesi rabl e trees and other l andscape features . Dtch bottom shoul d besi zed and graded t o carry runoff at non-erosi ve vel oci ti es whenfeasibl e . When erosi ve vel oci ti es wl l occur, erosi on control measuresshoul d be provided . Fi l l side sl ol . zs shoul d be 4: 1 or f l atter forrol l i ng terrai n . I t i s general l y accepted that si de sl opes of 4 : 1 arereasonabl y safe and very often can be provided at l ess cost than the costof guardrai l . General Motors Provi ng Grounds tests i ndi cate that si desl opes 6 : 1 provi de i nsurance agai nst overturni ng even under adversecondi ti ons . I nterceptor di tches, di kes or terraces shoul d be providedwhere needed t o i ntercept runoff and conduct i t away fromsl opes atnon-erosi ve vel oci ti es . Roadsi de di tches on the upstreamsi de of roadsshoul d be rel i eved wth cul verts across the road at i nterval s spaced soas t o prevent excessi ve erosi on of the upstreamdi tches . Dtches andchannel s shoul d be desi gned for hydraul i c eff i ci ency by customary Corpshydraul i c desi gn cri teri a to accommodate runoff . Proper erosi on controlmeasures shoul d be provided as needed, desi gned i n accordance wthcustomary Corps cri teri a . Drai nage and erosi on control shoul d bedesi gned i n accordance wth TM5-820-4, Drai nage and Erosi on Control . ;Drai nage for Areas Other Than A rfi el ds . Addi ti onal sources ofi nformati on on recreati on road drai nage and erosi on control are thevari ous state highway manual s and the Soi l _ Ccaservati on Servi ce design .These ai ds may be used when they are more sui tabl e for the prevai l i ngcondi ti ons .

f . Gradi ng Desi gn of gradi ng shoul d gi ve consi derati on t o roadsi desafety and aestheti cs . Transi ti ons between sl opes, and sl opes andnatural ground shoul d be rounded and warped as requi red for safety and tobl end wth the surroundi ngs . Vegetati on can usual l y be restored eventhough i t may take consi derabl e time and expense, but unsi ghtl y l andform l eft at the end of constructi on usual l y are di f f i cul t and costl y tocorrect . See Fi gures I V-3 and I V-4 of AASHTO "A Pol i cy on Geometri cDesi gn of Rural Hghways", 1965 f or roundi ng of typi cal cross secti ons .Fi gure 2-9 shows mnimumgradi ng for a recreati on road . Gradi ng shoul dbe as l i ght as feasibl e .

g . Obstructi on Cl earance . Obstructi on clearance i s the di stance tobe provided, measured f romthe edge of the (paved) road surface, whichshoul d be free of obstructi ons hazardous t o vehi cles i f struck by themObstructi ons i nclude structures, trees, pol es, uti l i ty features, andstandards whi ch are not of yi el di ng, break-away or frangi bl e typei ncl udi ng si gn supports . Again recreati on road cl assi f i cati on must hegi ven ful l consi derati on i n determni ng appl i cati on of the gui dance setout here . As cl assi f i cati on of the road and the i ntended use thereofmeets wth the acti vi ty area, i . . e . , pi cni cki ng and campi ng, obstructi on

2-25


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EM 1110-2-41031 Dec 82cl earance becomes l ess and l ess important and i nteQri ty of t heenvi ronment begi ns t o have stronger demands on how obstructi on clearancei s appl i ed .

Fi gure 2-9 Gadi ng f or Recreati on Roads i n Acti vi ty Areas(1) Hori p, -tal . The hori zontal clearance i s measured as shown onFi gure 2-7 f rom t he edge of the road surface . Tn t he obstructi onclearance wdth, themaximumslope (shoul der or side sl ope) shoul d notexceed 6 : 1 ( 6 hori zontal t o 1 vert i cal ) . Metal beamguardrai l or otherhi ghway department standard devi ces may be requi red at pl aces al ong thehi gher speed (40 mph or more) access road t o protect vehi cl es whereususual condi ti ons or economcs restri ct the clearance that can beprovided . Mai ntenance of the i ntegri ty of obstructi on cl earance al ongroads i nsi de acti vi ty areas must be j udged on the meri ts of safetyi nvol ved and servi ng park aestheti cs at the same time Abrupt changes i ntype of road (f rom40 t o 50 mph access road to 20 or 30 mph ci rcul ati on

road) thus causi ng hazardous condi ti ons shoul d be avoided because of theabrupt changes i n hori zontal . obstructi on clearance_ that coul d occur .Mnimumhori zontal obstructi on cl earances shoul d be as gi ven i n Tabl e2-11 .

2-26


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(2) Verti cal . For roads whi ch wl l be used onl y by passenger cars(Desi gn Vehi cle P) the mnimumvert i cal cl earance shoul d be 10' . Forroads desi gned for Desi gn Vehi cle SU the vert i cal cl earance shoul d be 15' .h . Crosswalk . Pedestri an wal ks crossi ng roads (cross walks) shoul dhe si gned and marked i n accordance wth ANSI f , . 1-1978, parti cul arl yparagraphs 3B-13 and 2C-33. Chapter 5 of thi s manual . , gi ves a di scussi onon walks and Chapter 5 di scusses trai l s and trai l crossi ngs of roads .

Road

Guardrai l s and Del i neators .

Tabl e 2-11MNMUMHORIZONTAL OBSTRUCTI ON CLEARANCE*

Desi gn Speed (MPH

2- 2 7

EM 1110-2-41031 Dec 82

*On a case by case basi s there may be times when these di stances shoul dbe waved i n the i nterest of park aestheti cs . Users shoul d enj oy thesurroundi ngs wthi n a park wth cauti on si nce both safety and pl easureare to be served.

(1) General . Guardrai l s are used where vehi cles acci dental l yl eavi ng the highway woul d be subj ected to hazard General l y, suchhazards are f i xed obj ects al ong the pavement edge, f i l l s on steep grades,l ong through f i l l s, or f i l l s on sharp curvature, but other poi nts equal l yhazardous are al ong water courses, bodi es of water, escarpments, al ongdeep di tches i n cuts (parti cul arl y wth rock exposed) and siml arl ocati ons . The more dangerous poi nts al ong a highway are obvi ous fromthe pl ans, but the overal l need for guardrai l s i s best determned byfi el d i nspecti on as the gradi ng nears compl eti on I nstal l ati on shoul dmade before the highway i s opened to traff i c .

be

(2) Guardrai l s on f i l l s . The need for guardrai l s on f i l l s i sdef i ni tel y rel ated to the sl ope. General l y theymay be omtted where i ti s practi cabl e to provi de sl opes of 4 : 1 (four hori zontal to one vert i cl e)or f l atter because a dri ver, forced onto such a sl ope, has a chance ofregai ni ng control of hi s vehi cle. I n som cases i t i s economcal tof l atten embankment sl opes to 4: 1 or l ess i nstead of constructi ngguardrai l . , provided ri ght-of -way i s avai l abl e. For roads that must he

Cassi f i cati on 20 or l ess 30 40 or moreAccess 10' 10' l h'C rcul ati on Edge of wdened Edge of wdened -Pavement +2' Pavement +4' -Servi ce


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EM 111. 0-2-41031 Dec o?constructed on di ff i cul t terrai n (mostl y rol l i ng to mountai nous) depth off i l l cri teri a shoul d be fol l owed. The park road desi gner must besensi ti ve to terrai n condi ti ons as the road tvpe passes fromaccess t oci rcul ati on t o the poi nt of users desti nati on i n an acti vi ty area orf aci _ l ; tv . When consi deri ng f i l l sl opes and drai nage di tch design needscomparati ve cost studi es of guardrai l versus f l atter side sl opes shoul dbe made . See di scussi on i n AASHTO "A Pol i cy on Geometri c Desi gn ofRural Hghways", 1965 . Savings i n maintenance cost and for safety can bereasons for i ncreasing the f i l l depth at which i t i s economcal t of l atten sl opes rather than use guardrai l . However, where there i s anacci dent prone situati on, even wth fl at sl opes, there usual l y i s reasonfor guardrai l s . Wth headwal l s, i nterceptor drai nage channel s, trees, orother obj ects present on the f l at sl opes, the hazard i s not greatl vdi f ferent fromthat on steep slopes .

(3) Other hazards to be protected by guardrai l . . t "Thi l e guardrai l sl argel y are used on f i l l secti ons, thei r need i s recogni zed at abruptchanges i n road cross secti on, at approaches t o structures, or atdrainage pi ckup poi nts, even i n cut secti ons t o provi de the essenti aldel i neati on or warni ng I n such i nstances, del i neators general l y aremore sui tabl e, wth guardrai l s bei ng onl y i .nfrequentl . y requi red

(4) Choi ce between guardrai l or del i neator . The choi ce of provi di ngguardrai l s or del i neators l argel y i s a matter of the hazard i nvol vedGuardrai l s are desi gned to resi st impact by defl ecti ng the vehi cl e sothat i t conti nues t o move at reduced vel oci ty al ong the guardrai l . Anyabrupt stop of a vehi cl e i s dangerous and gui depost or proi ecti on onguardrai l s whi ch mght snag a movi ng vehi cl e i s not desi rabl e . Thesudden stop may be more hazardous than the al ternati ve . Del i neators areespeci al l y desi rabl e i n areas subj ect to fog Ref l ector surfaces orbuttons on themgreatl y improve thei r vi si bi l i ty at ni ght, when i t i sneeded most .

(5) Del i neators . Del i neators shoul d be desi gned so as not to resi stimpact . They are l ess costl y than guardrai l , but shoul d not be used i nl i eu of guardrai l where vehi cl es need structural restrai nt to preventthemfroml eavi ng the road. Locati ons frequentl y are encountered wheremany dri vers are confused regardi ng the di recti on of the road,parti cul arl y at ni ght . Del i neators general l y are used at such pl aces .I n general , hori zontal . curves can be outl i ned suff i ci entl y by del i neatorson the outsi de of curve onl y . They shoul d be conti nued for some di stanceon tangents at t he ends of the curve .

(6) Locati on . Except at turnouts, guardrai l s and del i neators shoul dbe l ocated at a constant di stance fromthe edge of pavement t o avoi dpossi bl e confusi on i n i ncl ement weather as t o thei r l ocati on . Theyshoul d be l ocated somewhat back from the usabl e pavement l i . ne and atabout the same el evati on. When guardrai l i s used i t i s desi rabl e for a

2- 28


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2-5 . I ntersecti on Desi gn El ements .

c . MnimumDesi gns f or Sharpest Turns (Fi l l et Radi i ) .

2- 2 9

FM 111. 0-2-41031 Dec 82short di stance on the traf fi c approach end to sweep i t outward anddownward and t i e i t i nto the ground i n order to l essen possi bl e di rectend impact and t o provi de a ful l vi ew t o the dri ver .

(7) Vi si bi l i ty . To be fu l . v effecti ve, guardrai l s and del i neatorsshoul d be hi ghl y vi si bl e and wel l maintained wth ref l ector buttons orref l ectori zed materi al . Such hi ghl y vi si bl e treatments are good warni ngsfor hazardous si tuati ons and add measurabl y to the comort and ease ofri di ng al ong the roadway . Thi s factor al one may i n many i nstancesprovide the reason for thei r provi si ons .(8) Desi gns . Guardrai l and del i neators shoul d be of desi gnscustomari l y used by the state highway department, however, consi derati onshoul d be gi ven t o the use of treated timber when wood meets, therestrai ni ng needs . See Figure 2-8 . When the roadway secti on requi resmore sure guardrai l hol di ng capaci ty, metal , concrete, or masonry wal l

types shoul d be consi dered . Del i neati on and quasi guardrai l devices,such as gui deposts, boul ders or other obi ects whi ch woul d i n themsel vesbe hazards i f struck by vehi cl es shoul d not be used.

a . General . An i ntersecti on i s the poi nt where two or more roadsj oi n or cross . Each segment of road radi ati ng froman i ntersecti on i scal l ed l eg An i ntersecti on i s an important part of a highway since muchof the ef f i ci ency, safety, speed, cost of operati on, and capaci ty i si nf l uenced by i t . An i ntersecti on must handl e through traf fi c as wel l asturni ng movements . I ntersecti on design shoul d gi ve consi derati on to suchfeatures as al i gnment, sight di stance, pavement wdth, grades,superel evati on, and curbed channel i zati on i sl ands .

b . Si ght Dstance . The operator of a vehi cl e approachi ng ani ntersecti on shoul d be provided unobstructed vi ewof the enti rei ntersecti on Al l i ntersecti ons for Corps recreati on roads shoul d becontrol l ed i ntersecti ons, i . e . , STOP and YI ELD si gns shoul d be providedat al l i ntersecti ons . Figure 2-2 shows design data for desi rabl e si ghtcondi ti ons at the i ntersecti on of recreati on and publ i c roads .

(1) General . Where i t i s necessary to provide for turni ng vehi cleswthi n mnimum space, as at unchannel i zed i ntersecti ons, the mnimumturni ng paths of the desi gn vehi cles appl y . The paths of concern are themnimumattai nabl e at l ow speed, l ess than 10 mph, whi ch are a l i t t leabove the mnimumpaths of nearl y al l vehi cles i n each cl ass and,consequentl y, of fer some l eeway i n dri ver behavi or . Layouts patterned tof i t these desi gn vehi cl e paths are consi dered sati sfactory as mnimumdesi gns . I n the desi gn of the edge of pavement for the mnimumpath of a


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EM 1110-2-41031 Dec 82gi ven design vehi cl e, i t i s assumed that the vehi cl e i s properl yposi t i oned wthi n the traff i c l ane at the begi nni ng and end of thei . e . , 2 feet fromthe edge of pavement on the tangents approachi ngl eavi ng the i ntersecti on curve .

(2) Mnimumradi us for i nner edgeof pavement surface( a) Design vehi cl e P (passenger car) . The30 feet .

2- 30

or f i l l et .mnimumradi us shoul d be

(b) Desi gn vehi cl e SU (Si ngl e uni t truck or bus) . Theradi us shoul d be 50 feet . I n any desi gn permtti ng the SU desi gn vehi cl eto turn on i ts mnimumpath wthout swngi ng wde, the front overhangswngs out 12 feet fromthe edge of tangent pavement on the far end ofthe turn, the vehi cl e ful l y occupying a 12-foot l and on theWth 10- or 11-foot l anes, the vehi cl e woul d encroach on anl ane . To precl ude thi s, edge of pavement radi i l arger thani ndi cated woul d have to be used.

mnimum

turn,and

crossroad .adj acentthe mnimum

(3) Addi t i onal mnimumedge of pavement desi gns . I t i s emphasi zedthat the radi i prescri bed herei n are mnimum and may be i ncreased wthi na reasonabl e l imt . For addi ti onal desi gn i nformati on see AASHTO "APol i cy on Geometri c Desi gn of Rural Hghways", 1965 . Tabl e 2-12 gi vesmnimumradi i for i ntersecti on turns at vari ous angl es .

d . SReed Change Lanes . Speed change l anes woul d rarely be j usti fi edexcept where the access road to recreati on l and i ntersects a road orhi ghway of a state, county or ci t y system They are not j usti fi ed f ori ntersecti on wth a publ i c road or hi ghway unl ess i t i s travel l ed byrel ati vel y l arge numbers of vehi cl es at rel ati vel y hi gh speeds . Foraddi t i onal gui dance refer to AASHTO "A Pol i cy on Desi gn of UrbanHghways and Arteri al Streets, 1973.

an

e . Traff i c Control Devi ces . A l recreati on road i ntersecti onsshoul d be provi ded wth traff i c control devi ces i n accordance wth theManual on Uni formTraf f i c Control Devi ces for Streets and Hghways,ANSI D6.1-1978 . The mnimumcontrol shoul d be erecti on of ri ght-of-wayassi gnment si gns, ei ther STOP or YI ELD Were needed STOP AHEAD or YI ELDAHEAD si gns shoul d be erected. Cross Road Si gn (W2-1, W2-2, W2-3), TSymbol Si gn (W2-4) and Y Symbol Si gn (W2-5) shoul d al so be used asappropri ate on roads wth desi gn speeds i n excess of 30 mph which areassi gned the ri ght-of-way at the i ntersecti on ; i . e . , STOP or YI ELD si gnsi nstal l ed on the other road l eg or l egs at the i ntersecti on.I ntersecti ons are about the most dangerous pl aces on roads and deservecareful design efforts . Were traff i c j usti f i es, curbs and/or i sl andsmaybe used t o channel i ze traff i c and they shoul d be desi gned i naccordance wth l ocal state hi ghway department cri teri a or AASHTOpol i cy. A so consul t, ANSI 6. 1-1978 .


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Tabl e 2-12MNMUMEDGE OF PAVEMENT DESI GNS FOR TURNS AT TNTERSECTIONS*

Desi gn Angl e Simpl evehi cle of curveturn radi us

*Fi l l et radi i**Use mnimumradi i of 30' for vehi cle P, and 50' for vehi cle SU

FM 1110-1- ! 41031 Dec : 3?

PSU

degrees30

feet100100

P 45 100SU 75P 60 40SU 60P 75 35SU 60P 90 30SU 50P 105SUP 120SUP 135SUP 150SUP 180 x4cSU U-Turn


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EM1110-2-41031 Dec 822-6 . Drainage Structurces .

a . Hydraul i c Design Frequency . Cul verts shoul d be desi gned t o passthe runoff for hydraul i c frequenci es of 2 t o 10 years . Mnor bri dgesshoul d be desi gned for hydraul i c frequencies of 5 to 25 years . ' Maj orbri dges (these wl l rarel y be constructed i n parks) shoul d he desi gnedfor frequenci es of 25 to 50 years . Sel ecti on of the design frequencyshoul d be i nf l uenced by consi derati on of the effects of traff i ci nterrupti on, potenti al damage fromrunoff exceedi ng design runoff, andthe importance of the road and structure si ze (See TM 5-820-4) .b . Cul verts . D tches shoul d be rel i eved frequentl y to avoi dcarryi ng runoff for l ong di stances i n roadsi de di tches . I n l ocati ngstructures, the natural drai nage pattern shoul d be preserved as much asfeasibl e . Contractor' s opti on for use of rei nforced concrete orcorrugated metal for pi pe cul verts shoul d be permtted where feasibl e .

Careful attenti on shoul d be gi ven t o proper setti ng of the outfal li nvert . Outfal l protecti on and/or energy di ssi paters shoul d be provi dedwhere outfal l vel oci ti es can be erossive (See TM 5-8

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Design of Recreation Areas