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Malcolm H. Ray, P.E., Ph.D.Christine E. Conron186 Staples Hill RoadCanton, Maine 04221
Large jets like the Boeing 747‐400 have seating for 416 people. If two large jets crash every week, 43,000 people could die in one year. Would this be tolerated?
About 43,000 people die on US roads every year.
Meyer,M.D., “Crashes vs. Congestion-What’s the Cost to Society?,” Cambridge Systematics, Inc., 4800 Hampden Lane, Suite 800, Bethesda, Maryland 20814, March 5, 2008
“Safety should be considered first, every time and at every stage of a project. Make safety your first consideration in every investment decision.”
FHWA Safety, http://safety.fhwa.dot.gov/index.cfm, May 20,2009
“…VE studies are to be performed during the design process… all costs associated with:
environmental studies, preliminary engineering, final design, ROW, and construction
should be used to determine a project's overall cost.”
USDOT Construction, http://www.fhwa.dot.gov/construction/cqit/vecp.cfm, May 20, 2009
“…VE studies are to be performed during the design process… all costs associated with:1. SAFETY or the potential for crashes,
environmental studies, preliminary engineering, final design, ROW, and construction
should be used to determine a project's overall cost.”
Is it more cost effective to…Blast 10 meters of clear zone through ledge for 7 kilometers or divide 10 kilometers of highway? Extend a culvert with grading and traversable grate or install a headwall with guardrail?Increase ROW costs to flatten sideslopes or install barrier?
Develop an integrated risk‐based highway design process in one user interface.Enable the highway designer to review the costs of a highway design and construction with safety costs as a direct consideration.
Different Cross‐sections?Different Design Speed?Different Alignments?
A Policy on Geometric Design of Highways and Streets (Green Book)The Roadside Design Guide.
• How many crashes will occur over the design life?
http://www.highwaysafetymanual.org/PastPresentations/Generic%20HSM%20November%202008.pdf, May 20, 2009
How much savings will the median generate in crash costs?How much will it cost to install? Is it worth it or should I do another project?
Glennon noted in 1974 if there were unlimited funding, then all roadside safety problems could be treated using the warranting approach.
Long history of probabilistic modeling: Hutchinson 1962 through NCHRP 17‐11 and 17‐22ROADSIDE, 1989RSAP, originally 2003 and update ongoing
Probabilistic Methods for Highway Design using RSAP2010 & Modern CAD‐based Highway Design Tools
3.144 km (1.954 miles)Horizontal curves of 150 meters – 500 metersCombinataion of tangents and curves
Design Criteria:AASHTO 2004 Metric , 50 km/h Rmin=86m, eMax 4%K = 138 (crest‐7 no PSD) and 13(sag)
Num Type Length Radius Direction Start StationEnd Station Delta angle Chord lengt Chord Directio1 Line 8.761m N22° 09' 31"W 10+000.00m 10+008.76m2 Curve 41.824m 150.000m 10+008.76m 10+050.59m 15.9757 (d) 41.689m N14° 10' 15"W3 Line 99.189m N6° 10' 59"W 10+050.59m 10+149.77m4 Curve 211.671m 200.000m 10+149.77m 10+361.45m 60.6392 (d) 201.929m N36° 30' 09"W5 Line 95.391m N66° 49' 20"W 10+361.45m 10+456.84m
Object Data:
No. PVI Station PVI Elev. Grade In Grade Out A Curve Length K R1 10+032.19m 185.683m 5.15%2 10+112.11m 189.798m 5.15% 0.26% 4.89% Crest 44.686m 9.132 913.236m3 10+177.04m 189.964m 0.26% 6.44% 6.18% Sag 85.167m 13.772 1377.169m
Object Data:
“Value studies are made by multi‐disciplined teams who's objective is to:
1. investigate/analyze the design of an existing project, 2. analyze project functions and costs, 3. creatively speculate on alternative ways to perform the various functions,
4. evaluate the best and/or least life‐cycle cost alternatives, 5. develop acceptable alternatives into fully supported recommendations, and
6. present the team's recommendations to management.”
USDOT Construction, http://www.fhwa.dot.gov/construction/cqit/vecp.cfm, May 20, 2009
Interactive Highway Safety Design Model (IHSDM)SafetyAnalystRoadside Safety Analysis Program (RSAP)Arizona Local Government Safety Project Analysis ModelSafeNETPLANSAFEThe SafetyAdvisor
Keep in mind what’s already been done.Friendly/Familiar user interface to encourage use by designer.Plan for the future.
Ongoing research like RSAP and IHSDMComputers and programs evolve faster than…
43,000 people die each year on our roads.Risk‐based approach will allow engineers to select the design alternative that will make the greatest improvement in safety at the least cost. Questions?