Tripi Tripgen PPT

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BASICS OF ITE TRIP GENERATION

TRANSPORTATION IMPACT FEES

Eric J. Tripi, P.E., PTOE

Iteris, Inc.

505 Belle Hall Parkway, Suite 202

Mount Pleasant, SC 29464

Innovation for better mobilityInnovation for better mobility

2011 Growth and Infrastructure Consortium Conference October 27th, 2011



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Presentation A enda

.

II. Basics of ITE Trip Generation

. er e ey oun y, mpac ee r nance

IV. Two Independent Impact Fee StudiesV. Final Agreement

Questions



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Who Am I?Eric J. Tripi P.E., PTOE

Work for Iteris, Inc.

,

Over 17 years of Traffic and Transportation Consulting

Registered Professional Engineer (P.E.) in several states

Certified Professional Traffic O erations En ineer PTOE



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Where Am I?



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Education

Michigan State University - BSCE

University of Nebraska - MSCE



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Other Notes

updating of ITEs Manual of Transportation Engineering Studies, 1st

ed.

Served as President of the South Carolina Section of ITE in 2007.

Adjunct professor at The Citadel in Charleston, South Carolina,.

Certified National Highway Institute (NHI) instructor and currently

on-call to teach at different locations across the United States.



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Who Is Iteris? 20+ Offices in 14 States

HQ in Santa Ana, CA Specialize in:

Traffic Engineering

Intelligent Transportation Systems (ITS)



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What Do I Do? Traffic Impact Studies

Level of Service Analysis

Parking Studies

Traffic Signal Design

Intelligent Transportation Systems (ITS)



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Basics of ITE Tr i p Gener at ion

Who is ITE

Institute of Transportation Engineers

Founded in 1930

,

Over 90 local chapters and 130 student organizations

Educational and Scientific organization



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What is Trip Generation?

The estimated peak hour and daily site traffic volumesfor a particular land use.

trips and land use characteristics

x s ng esources

Trip Generation, 8th Edition, 2008, Volumes 1, 2 and 3

Tri Generation Handbook An ITE RecommendedPractice,

o 2nd Edition published by ITE, June 2004



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What is Trip Generation Used For?

eg ona s u es Considers land use and socio-economic characteristics

Site im act anal sisAnalysis of trip generation of specific land uses

Zoning and land use planning applications

Sizing transportation system and individual facilities

Impact fee determination

Environmental assessment Traffic impacts on air and noise



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A Trip or Trip End Single or one-directional vehicle movement to or from a site/area

One-way movement

Office

Peak-Hour Trip Generation

50 entering trips

50 150

Development

200 total trip ends per hour

Total of all trips entering and exiting a site during a designated time

period



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Basi cs of ITE Tr i p Gener at ion Tr i p Types

Diverted Trips

Trips that are diverted from nearby roadways

o Required to use another roadway to access site

Adds traffic to streets directly adjacent to development site

o Not to nearby major roadways

Direction of travel upon exit may be similar to that of pass-by trips

Difficult to identify



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PROPOSED

EnteringDiverted-Link Trip

Pass-by trips are

made as an

Exiting Pass-by Trip

Exiting Primary Trip

Enterin Primar Tri

Entering Pass-by Trip

Pr imary trips

are the main

reasons for LEGEND

ExitingDiverted-Link

Trip

the trip

Diverted-l ink t rips are at tracted from

the passing traffic on nearby

roadways but require a diversion from

Primary Trip

Pass-B Tri

Trips Prior to Visiting the DevelopmentTrips After Visiting the Development



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the intended travel pathDiverted-Link Trip


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Internal Ca ture Tri s

Trips made within mixed-use developments

Trips are on internal roadways only and do not

use adjacent main roadways

Result in trip reductions for mixed-use

develo ments

Example of Internal Capture Trip: Driving/Walking

from your office to a restaurant within a large

mixed-use development, but via internal

roadways only.



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Source: ITE Tri p Generat ion Handbook, Second Edit ion ITE 2004


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Internal Ca ture Tri s Notes

Existing data based on 1990s FDOT methodology/research New Florida Community Capture Methodology - 2009

Newly completed research (NCHRP 8-51), results have shown*:

o ITE Method overestimated traffic

o - , . .,

reduced estimation errors by 1/5th to 1/3rd of other methods

More data needed

*Source: TTI, 2010 ITE Annual Meeting Presentation



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Basi cs of ITE Tr ip Gener at i on Peak Per i od Def ini t i ons

1-hour weighted average vehicle trip generation rate at a site between

7:00 a.m. and 9:00 a.m. or between 4:00 p.m. and 6:00 p.m.

Peak hour of the generator

peak hours

o Hi hest volume hour of site traffic durin the AM or PM eriod

o May not coincide with trip rate for peak hour of adjacent street traffic



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Basi cs of ITE Tr i p Gener at i on ITE Tr i p Gener at i on Manual

ITE Trip Generation ,

United States and Canada since the 1960s

o With limited transit service

o Without nearby pedestrian amenitieso ou rave eman managemen programs

Data received on voluntary basis



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Basi cs of ITE Tr ip Gener at i on ITE Tr i p Gener at i on Manual

Trip Generation Cautions Data compiled over five decades

Various geographical locations in the United States and Canada

Various times of the ear

Various durations of data collection

Other sources of variations



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Basi cs of ITE Tr ip Gener at i on ITE Tr i p Gener at i on Manual

10 main land use categories and 162 specific landuses or s an erm na s

Industrial Residential

ns u ona

Medical Office

Lodging

Recreational

Retail

Services

Sample independent variables and time periods No. dwelling units

Weekday, Saturday, Sunday

. .

No. employees

Peak hour of generator



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Weighted average

standard deviation

Data plots

Regression equations



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Key Note:

r p genera on ana ys s or a propose eve opmen

influences transportation decisions and financialcommitments, therefore

Care should be taken when determining which land usecode to use: Review and compare descriptions

Select the land use code that most closel fits intended use of

the proposed development Select appropriate time period



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Example Situation Shopping Center

500,000 Square Feet

Analysis Period PM Peak Hour of adjacent

street traffic

Select Land Use Code 820, (Pg 1502 of Trip

th, .

Regression Equation

Ln(T) = 0.67Ln(x) + 3.37

With 49% entering and 51% exiting

T = 0.67Ln(500) + 3.37 = 1870 trip ends per hour

Entering trips = 53 0.49 = 916 trips

= = .

Assume all t rips are pr imary tr ips



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When to collect data for local study

ITE land use category is not available

Inade uate number of studies exist in ITE data

Size of site is outside range of ITE data points

To validate Trip Generation data for local application



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Trip Generation Summary

Use the data carefully

Understand how the data was collected

Understand the sites surveyed within each land use

Pass-b and Internal Ca ture Tri Deductions

Weighted Averages vs. Regression Equations



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. ,

Ordinance



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Berkel ey Count y, SC Impact Fee Or di nance

,

Two existing businesses wished to build new,

Each owner was assessed an Impact Fee they were

so we were called to assess the situation.



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Berkeley County Ordinance Impact Fee Calculations

Impact Fee = (NNWT) x (TED) x (COST) x (CDR)

Where:

NNWT = Net New Weekday Trips (includes pass-by and capture trip reductions)TED = Trip end discount of 50%

COST = Cost per trip for Service Zone 1, $402.25

= er ounty ounc o cy o max mum a owa e mpact ee wbe charged (85% for Independent Studies).



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Ber kel ey Count y, SC Impact Fee Ordi nance



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Studies



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Two Independent Impact Fee St udies

What kind of land use is this?

Sells motorcycles, watercrafts, ATVs, utility vehicles

Sells parts

Provides on-site service

Typically low number of employees (


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SITE #1

Existing Site Characteristics

Building 5,000 sf, with additional 1,250 sf of storage

ou s e e u ng

7 employees

O en 10AM-6PM, Mon-Sat

Future Site Characteristics

17,000 sf

7 Employees

Open 10AM-6PM, Mon-Sat



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SITE #2



ou s e e u ng

15 employees



43,559 sf

15 Employees




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Assessed $41,700 in impact fees based on existing

Berkele Count Ordinance methodolo ies

Assessed $126,000 in impact fees



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Impact Fee Calcs for Site #1 (per County Ordinance):

17,000 Square Feet of Future Building Area

Apportioned:11,000sf = Warehouse (11 x 4.96 = 55 Trips)5,000sf = Retail (5 x 86.56 = 433 Daily Trips x .52 Pass-by = 225 Trips)1,000sf = Office (1 x 15.65 = 16 Trips)

Impact Fee = (NNWT) x (TED) x (COST) x (CDR)= (296) x (0.50) x (402.25) x (0.70) = $41,673

Total Fee = $41,673



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Data Collection for Independent Study (per Berkeley

County Ordinance)

Surve ed Ins/Outs of existin sites durin business hours

Study conducted on an average weekday (Tuesday-Thursday) for

two different weeks

Classified number of Motorcycles versus Cars/Trucks trips



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Conclusions of Site #1 Independent Study



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76 average daily trips

Conservative assumption that 25% of the trips are pass-by in

nature

NNWT value of 76 x 0.75 = 57 was used (vs. 296)

The Impact Fee becomes:

Impact Fee = (57) x (0.50) x ($402.25) x (0.85) = $9,744.51

A $33,000 Savings



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BUT WAIT.THE NEW BUILDING IS BIGGER!!!

Doesnt this mean there will be more trips?

Not necessarily

Number of Employees to remain the same

Much of the increased space being used for storage andworkshop

No new services offered



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.

BE THAT EASY DID YA?



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Final Agreement

County Comments/Recommendations for Site #1 Study:

25% Pass-by assumption ok

Insisted the site would generate additional trips with larger building

Compromise: assume existing building square footage is 50% bigger

Thus NNWT value increases to 117.97


Impact Fee = (117.97) x (0.50) x ($402.25) x (0.85) = $20,167.71

till a 21,410 avings



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Final Agreement

SITE #2



ou s e e u ng

15 employees



43,559 sf

15 Employees




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Final Agreement




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Final Agreement


323 average daily trips

Conservative assumption that 25% of the trips are pass-by in nature

Assumed existing square footage was 50% higher (per prior study

County recommendation)

NNWT value of 316 was used.


mpact ee = x . x . x . = , .

A $72,000 Savings



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Final Agreement

County Comments/Recommendations on Site #2 Study:

25% Pass-by assumption ok

Compromise: assume existing building square footage is 20% bigger

Thus NNWT value increases to 380


Impact Fee = (380) x (0.50) x ($402.25) x (0.85) = $64,963.38

Still a $61,000 Savings



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Final Agreement

Moral of Story:

ITE Trip Generation used to calculate Impact

Fees needs to be carefully reviewed

especially for small unique developments.



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uestions are Welcome! uestions are Welcome!



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Tripi Tripgen PPT