Travel Demand Management Effectiveness Report

8/3/2019 Travel Demand Management Effectiveness Report

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TravelDemandManagement

An analysis of theeffectiveness of TDM plans

in reducing traffic andparking in the Minneapolis-St.

Paul metropolitan area.

ByMike Spack, PE

Mike Bultman, EITKirk Pettis, EIT

Jenni Thompson, RLA, AICP, LEED APJoe Collins, RLA

January 22, 2010

3268 Xenwood AvenueSt. Louis Park, Minnesota 55416

952-378-5017www.SpackConsulting.com

www.MikeOnTraffic.com


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Has TDM beenscientifically proven to

reduce traffic & parking?By how much?

Introduction

ThegoalofaTravelDemandManagement (TDM)Plan istoencouragethereductionofsingle

occupancy vehicle use during rush hours. These plans potentially have many benefits for all

stakeholdersinanofficecomplexincluding:

Improvethe

Developers

bottom

line

by

reducing

the

number

of

parking

stalls

required

andincreasingbuildingsquarefootagecapacityonthesite.

DecreasePropertyOwners/Managersmaintenancecostsbyreducingparkinglotsurface

area.

CreatemorecommutingchoicesforTenantsandtheiremployees.

Reducetherunoffimpactonwaterqualitybyreducingtheimpervioussurfacearea.

Delaytheneedfornewroadconstructionbyreducingtrafficcongestion.

CreatepotentialpointsforLEEDcertification.

TDM isnotanewconcept. Itwasfirstproposed intheU.S.duringthe1970soilcrisis. Inthe

1990s,theCityofMinneapolis,MinnesotabeganrequiringformalTDMPlansfromdevelopers.

Since then many cities have adopted comprehensive transportation plans with new

requirementsorencouragementforTDMPlans.

Intheory,TDMPlanssoundlikeagoodidea. However,their

effectiveness has been minimally studied. Do TDM Plans

really reduce the amount of traffic generated by an office

building? Dotheythenrequirefewerparkingstalls? Several

positive case studies were found online, but no data on

mediocreornoneffectiveTDMplanswasfound. IsitpossibleTDMmaynotinfactprovideall

oftheclaimedbenefits?

Thepurposeofthisstudy istoobjectivelystudythetrafficandparkingcharacteristicsofoffice

buildingsin

the

Minneapolis

Metropolitan

Area

who

are

actively

implementing

TDM

Plans.

Our

studyobjectivesareto:

1. Determine the effectiveness of TDM Plans at reducing rush hour traffic by measuring

vehicleusegeneratedbyanofficebuildingwithaTDMPlanversusanequivalentoffice

buildingwithoutone.

2. QuantifyactualparkingneedsofofficebuildingswithactiveTDMPlanstodetermineif

lessavailableparkingwouldbesufficientversusthecurrentmandatedcapacity.

3. IdentifybestpracticestohelpmakefutureTDMPlansmoreeffective.

WhatisaTDMPlan?

It is a binding agreement outlining the efforts the owner/tenants will make to reduce their

trafficimpact.

The

developer

enters

into

the

agreement

with

the

city

which

extends

to

future

owners/tenants. TheTDM Plan listsstrategies to be implementedover timewith thegoal of

reducingtheamountoftrafficgeneratedbytheofficecomplex.

TDMPlansalsohaveconcretegoals. Typically, theirstatedgoal is to reduce parkingdemand

and traffic generation by 10 to 20% as compared to typical demand as documented in the

Institute of Transportation Engineers Parking Generation and Trip Generation reports. An


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importantpartoftheTDMPlanistohavemechanismsinplaceformeasuringeffectivenessover

time.

WhatarecommonTDMPlanStrategies?

Themost effectiveTDMstrategiesaffect thepocketbook. Peoplemakedecisionsabout their

commuteoptionsbasedoncost. Themoreexpensiveitistodrivetoworkbyyourself,themore

likelyyouaretoimplementapersonalTDMPlan. Caseinpoint carpoolingandtransitridershipgrewsignificantlywhengaspriceswereat$4agallon.

Therearefourmainstrategiespeopleusetoavoidtheexpenseofthesolodrivetowork:

Carpool Carpoolscanbesetup informallyby individualsorbyusingexistingcarpool

services(i.e.Rideshare).

VanpoolSponsoredbytheemployerortheMetropolitanCouncil,thetypicalvanpool

worksbyhavingonedriverpickupanumberofotherriders.

PublicTransitThisincludescitybusesandLRT.

Biking/WalkingThisincludesprovidingrobustsidewalkandtrailconnectionsbetween

officebuildingsandneighborhoods.

Governmental agencies can encourage alternate ride options by including bike lanes and

walking/biketrailsaspartoftheirtransportationplan. Developerscanencouragetenantuseof

alternate ride options by designing new sites with consideration for safe and comfortable

pedestrian and bicyclist building access. This includes emphasis on welllit sidewalks and

convenientaccesstobiketrails.

Butthebiggestimpactcanbemadebytheemployer. Someideastosupportemployeesuseof

alternaterideoptionsinclude:

Encourageuseofexistingcarpoolservices(i.e.Rideshare).

Sponsoremployeevanpools.

Work

with

transit

providers

to

ensure

transit

routes

are

convenient

and

schedules

are

timelyfortheiremployeesworkhours.

Provide access to secure bike storage and showers (with showers provided either on

siteorthrougharrangementswithalocalhealthclub).

Chargeemployees foronsiteparking freeparkingmakesthesolodrivetowork less

expensive.

Payemployeesnottoparkonsite(providingincentivetouseotheroptions).

Providefreeorsubsidizedparkingforcar/vanpools.

Allow flexible work hours to facilitate the setup of ridesharing and/or nonrush hour

commuting.

Provide a Guaranteed Ride Home program for ridesharing participants in case of

emergency.

Planning is important, but it is the follow through that leads to successful Travel Demand

Management. The building and site should have been built to encourage pedestrian activity.

Afterthat,successcomesdowntomarketingandpromotion. Keytoimplementationishavinga

designatedTransportationCoordinatorinsidethecompany.


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MostTDMPlansrequireaTransportationCoordinatorstaffpersonwithineachcompany. The

Coordinator position is usually approximately oneeighth of a full time equivalent, but is

somewhatdependentonthesizeofthecompany. TheCoordinatorshould:

Market and promote ideas and incentives available to employees for alternate

commuting options. The companys incentives should be well publicized in their new

hirepacket,ontheirintranet,andonpostersthroughouttheofficecomplex.

Providecontinuingupdatesandreminderstoencourageemployeeparticipation. Workwithvariousalternaterideproviderstogiveemployeesthemostoptions.

Coordinateannualperformancesurveys(typicallyrequiredinTDMPlans).

Keepuponthelatesttrendsinalternatecommutingoptions.

Companiesshouldparticipate intheBike/Walk/Bus/CarpoolWeekheld inmidMayeveryyear

asaneasywaytopromotetheirTDMprograms. ApplyingforMetroTransitsCommuterChoice

Awards program and the U.S. Environmental Protection Agencys Best Workplaces for

CommutersdesignationarebothgreatwaystopromotethecompanysTDMbenefits. Holding

an annual meeting to promote and discuss the companys TDM Plan is a good way to get

feedback.

Methodology

TheprojectteambeganbylocatingofficebuildingswithexistingTDMprogramswhichalsohad

standalone facilities to allow accurate data collection. Local transportation management

personnelwereveryhelpfulinprovidinglistsofemployerswithTDMplans. Aerialphotoswere

thenusedtodeterminesiteswheretrafficentering/exitingthesitecouldbeobservedbyfouror

less people. No downtown sites met this initial criterion because employees could park in

multipleparkingramps.

Asite

visit

was

then

conducted

of

the

top

ten

candidates

to

confirm

the

site

entrances

could

be

viewedbyfouror lesspeople. Theteamdeterminedthataminimumofsixsiteswereneeded

for comparison to produce a relevant conclusion. All sites needed to contain onsite parking,

haveknownemployeenumbers,andhaveTDMstrategies inplaceatthetimeofobservation.

Interviewswitheachpropertyortransportationmanagerwereconducteddiscussingstatistical

informationaboutthecompanyandallavailableinformationontheTDMplan.

TripgenerationandparkingcountswerecollectedonTuesdays,Wednesdays,andThursdaysof

nonholiday weeks to ensure the data was collected during normal weekday conditions. The

datawascollectedfrom7:009:00a.m.,11:00a.m.1:00p.m.,and4:006:00p.m. tocover

the peak traffic and parking periods. All of the data was collected during the Fall of 2009.

Phoneand

email

interviews

were

conducted

during

the

Fall

of

2009

to

ensure

the

site

and

TDM

datacorrespondedtothetrafficandparkingdata.


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Site ANo. of Stalls: 341No. of Employees: 300Occupancy: 100%Building Size: 166,000 sfLocation: Suburban

Site BNo. of Stalls: 270No. of Employees: 297Occupancy: 100%Building Size: 181,000 sfLocation: Urban

DescriptionofSites

Thissectioncontainsadescriptionofthesixsitessurveyed. Figure1attheendofthissection

containsamatrix identifyingwhichTDMstrategieseachsiteutilizedat the timethedatawas

collectedalongwithdemographicinformationabouteachemployer.

Site A is an energy company in a 2nd tier suburb of the

northwest metro. The company is located ina high density,

heavilytraveledshoppingarea. Thesiterequiredtwoproject

participants to count the access points. The traffic and

parking data was collected on October 13th, 2009. The

weatherwascoldand therewassnow/sleetduring theprior

nightcausingdifficulttravelconditionsforthemorningpeak.

This site is a LEED certified building. LEED points were earned in the area of alternative

transportationthrough itscloseproximitytoaregionalmasstransitstationand incentives for

carsharing,carpooling,andvanpooling.

Theentireparkingareacontains341stallsandhastwoaccesspoints. Theprimaryaccesspoint

is on the south side at a signalized intersection with a leftin turn lane provided for traffic

accessing the site. The collector road used to enter the parking lot is a four lane road used

primarilybyretailcustomersofthisarea. Asecondary,gatecontrolled,accesspointislocated

onthewestsideofthesite. Thisdriveway leadstotheparking lotofashoppingcenter. The

gate will open automatically for westbound traffic wishing to go into the shopping center

parkinglot,butascannercardisrequiredforthegatetoallowtraffictogoeastboundfromthe

shoppingcenterlotintotheenergycompanylot. Onlyasmallnumberofemployeeshavethese

cards,althoughthespecificnumberwasnotavailable. Itshouldbenotedthatduringthedata

collectiontherewereatleastthreeemployeeswhochosetoparkoutsidethecompanyparking

lotandinsteadparkedintheretailparkingadjacenttothesite.

Site B is a privately owned medical device manufacturer

occupying a newly constructed LEED certified multistory

officebuilding. Because thesite is located on the corner of a

frontageroadtoariverandasecondaryroad,onlyoneperson

was required to collect traffic and parking data for all of the

onsiteparkingareas.Thissiteiscategorizedasbeingurbanin

close proximity to the newly revitalized warehouse business

district (highdensitymixedusebuildings)andnewlyconstructedTwinsbaseballstadium near

downtownMinneapolis.

Thedata

was

collected

on

November

3,

2009.

The

weather

was

fair

and

mostly

sunny,

ahigh

of

62 Degrees, with moderate winds throughout the day. This site provides high incentives for

utilizing localtransitservices,theeffectsofwhichwereobservedduringthedatacollectionas

employeeswerefrequentlyseenusingthebusesatanearbybusshelter.


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Site CNo. of Stalls: 1,263No. of Employees: 1,314Occupancy: 100%Building Size: 292,000 sfLocation: Suburban

Site DNo. of Stalls: 1,546

No. of Employees: 1,400Occupancy: unknownBuilding Size: 418,064 sfLocation: Suburban

Thesitecontainstwosurfaceparkingareas.Theprimarytrafficwithinthissitewasgeneratedby

employees,visitors,deliveries/pickups,andcompanyownedvehicles(Trucks).Adescriptionof

eachparkingareaisasfollows:

1. Parking Area #1 contains 19 parking spaces with two access points. One access point

exitsontoadividedroadwaywithamedian,forcingtheexitingvehicleontoaoneway

road. This parking area is located directly at the front entrance to the building and

primarilyusedbyvisitorsordropoffs.2. ParkingArea#2contains251spacesandisafenced inareawithtwocardcontrolled

slidingfencegates.Duringtheobservation,bothofthegateswereopenduringnormal

businesshours.Thisareaisprimarilyusedbyemployeesanddeliveryvehicles.

SiteC isoccupiedby fourmanufacturingbuildings,whichare

all part of the same company. There are five total parking

areas for the campus. This site required four project

participants to count trip generation and parking lot usage.

This site is suburban, located outside of the downtown area.

The traffic and parking data was collected on November 11,

2009.

Theweather

was

dry,

50

degrees

with

moderate

winds

throughout the day. During peak period observations, the number of employees taking

advantageofthebusservicewasrelativelylow,presumablyduetothesitebeingsuburbanand

transfers likelyneededtoreachthedestination. Thissitealsoprovideshighincentivesforcar

poolingandvanpooling. Thepreferentialcarpoolingdesignatedstallswerefullthroughoutthe

peakperiods.

The two main parking areas and three small parking areas were included in the study. They

contain 1,263 employeebased parking spaces. It should be noted that a small visitor lot

containing approximately 30 stalls was not included in the calculations because data was not

collectedatthislot. Adescriptionofeachparkingareaisasfollows:

1. Parking

Area

#1

contains

680

stalls

with

two

access

points

and

is

used

by

Building

#1

and

Building#2.

2. ParkingArea#2contains510stallswiththreeaccesspointsandisusedbyBuilding#3.

3. ParkingArea#3contains50stallswithoneaccesspointand isusedbyBuilding#4. It

was noted that parking demand in this lot exceededstall capacity with some vehicles

parkinginnonparkingareas.

4. ParkingArea#4contains14stallswithtwoaccesspointsandisusedbyBuilding#1.

5. ParkingArea#5contains9stallswithoneaccesspointandisusedbyBuilding#1.

Site D is occupied by a pharmaceutical company with two

buildings.Onebuildingusesaparkingrampforemployeesand

the otherbuilding uses twosurface lots. Thissite required

threeproject

participants

to

count

trip

generation

and

parking

lot usage. This site is suburban, located outside of the

downtownarea. Thetrafficandparkingdatawascollectedon

October20,2009. Theweatherwasovercastwithlightrain,a

highof51Degreeswithmoderatewindsthroughouttheday. Duringpeakperiodobservations,

ashuttleservicecouldbeseenpickingupemployeesmultipletimeseachhour. Thissitealso

provides high incentives for carpooling and it could be seen that the carpooling designated

stallswerefullthroughoutthepeakperiods.


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Site ENo. of Stalls: 1,646No. of Employees: 2,303Occupancy: 93%Building Size: 573,116 sf

Location: Urban

Site F

No. of Stalls: 2,361No. of Employees: 2,304Occupancy: 69%Building Size: 712,868 sfLocation: Suburban

Thesitecontains1,546employeebasedparkingspaces.Adescriptionofeachparkingareaisas

follows:

1. Parking Area #1 consists of a parking ramp that contains 1,256 stalls with two access

pointsandisusedprimarilybyBuilding#1. Therewereveryfewcarsparkedonthetop

rampduringthestudyperiods.

2. ParkingArea #2consists of asurface lotwith 272 stalls with two accesspointsand isusedprimarilybyBuilding#2. Someoftheparkingstallswereoccupiedbyvisitors.

3. ParkingArea#3consistsofasmallsurface lotnear theparkingrampthatcontains18

stallswithtwoaccesspoints. Mostofthesestallswereusedforvisitorparkinggoingto

Building#2.

SiteE is occupied by three Minnesota government agencies.

Each agency occupies a separate multistory building but all

three agencies share open surface parking areas. This site

requiredfourprojectparticipantstocounttripgenerationand

parking lot usage. This site is urban in close proximity to

downtown

St.

Paul

(high

density

mixeduse

buildings).

The

traffic and parking data was collected on October 21, 2009.

Onthedaydatawascollected,theweatherwassteadytoheavyrain,ahighof46Degrees,with

moderatewindsthroughouttheday.Thissiteprovideshigh incentivesforutilizing localtransit

services and rideshare programs. It was noted during the observation; three local bus routes

provided frequent service. Most carpooling designated stalls were full throughout the peak

periods.

Four surface parking areas were observed for this study, providing 1,646 employee based

parkingspaces.Itshouldbenotedthatasmallvisitorlotcontainingapproximately20stallswas

notincludedinthecalculationsbecausedatawasnotcollectedatthislot. Adescriptionofeach

parking

area

is

as

follows:

1. ParkingArea#1contains186parkingspaceswithtwoaccesspoints.Thisareaisusedby

oneagency.

2. ParkingArea#2 contains 107 spaceswith asingle access cardcontrolled gate. This

areaissharedbytwoagencies.

3. ParkingArea#3contains18spacesadjacenttooneagency.

4. ParkingArea#4 contains1,335 spaceswith three cardcontrolled gates.This area is

shared by all agencies. This parking area encompasses landscape islands to separate

parkingforeachagency,butdoesallowfullconnectionthroughouttheentirelot.

Site F occupies two separate multistoried suburban office

buildings and is the world headquarters of an insurance

company.

Bothbuildings

share

amultiple

level

garage

and

a

surfaceparking lot. Themainbuildinghasafrontparking lot

mainly for visitor parking with 32 stalls. The parking garage

permitsentrywithsecuritycardclearance;havingacapacityof

2,130stalls. Thesharedsurfacelotwith199parkingstallshas

visitorparkingyet isprimarilyusedbyemployees. Vehicletripswerecountedbywatchingall

three entrances from one location. The garage vehicle occupancy data was provided by the

company. VehicletripswerecountedonNovember10,2009, insunnyconditionswithahigh


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temperatureof50degrees. Thissitehasabusstopinfrontofthebuildingalongtheadjacent

street.

Figure1SiteCharacteristicswithTDMStrategies

A B C D E F

Sit

e

Da

taSq.

Footage

166,000

181,000

292,000

418,064

573,116

712,868

Employees 300 297 1,314 1,400 2,303 2,304

Occupancy 100% 100% 100% unknown 93% 69%

Location Suburb Urban Suburb Suburb Urban Suburb

ParkingStalls 341 270 1,263 1,546 1,646 2,361

Tra

ffic

Da

taAMPeakHourVolume 179 96 365 481 564 683

PMPeakHourVolume 116 90 386 425 630 697

MaximumStallsParked 276 217 941 1,067 1,404 1,617

Transi

t

Serv

ices BusStop

Distance(Blocks) 1 2 1 2 1 1

EnhancedBusAmenities ShuttleServices

Park

ing

Management

Paid

HOVPreferential Pedestrian

Accessibility

Incen

tive

Programs

FreeTransit

DiscountedTransit Cash

NonmoneyRewards TaxSubsidies

Rid

esh

are

Progra

ms

Carpool/Vanpool Carsharing Bike

Sharing

GuaranteedRideHome RideshareMatching

Alt

erna

te

Sc

he

du

le Telework Flextime

Compressedweeks

Bic

yc

le

In

frastruc

ture

Racks Showers Lockers

CyclingImprovements

Walking/Cycling

Ad

vert

isin

g/

Commun

ica

tion Posters/Kiosks

Newsletters Internet

TransportationCoordinators Notes:(1)140employeecarpool,(2)17%carpool/vanpool,(3)334employees,(4)5employeesbike,(5)16employeesbike


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Results

Thissectionpresentstheparkingandtrafficgenerationdatacollectedatthesixsites. Thetraffic

generationdatashowsthea.m.andp.m.peakhourrates. Thenoontimepeakhouratallsix

siteswaslessthanthea.m.andp.m.peakhourrates,sotheyarenotrelevanttothisstudy. The

peakparking

occupancy

occurred

at

each

site

during

either

the

a.m.

study

period

or

noontime

studyperiod.

TrafficGeneration

Figure2showstheamountoftotaltraffic(enteringthesiteplusexitingthesite)generatedper

1,000squarefeetofbuildingateachsiteduringthemorningrushhour(thebusiest60minute

period between 7:00 and 9:00 a.m.). The

highest rate observed in the morning rush

hour was 1.25 trips per 1,000 square feet

while the lowest was 0.53 trips per 1,000

square feet. The average trip rate was 0.99

trips per 1,000 square feet, which is a 36%

reduction in trips compared to the industry

average rate of 1.55 documented in the

Institute of Transportation Engineers TripGeneration, 8th Edition. All six sites have aratelowerthanindustryaverage.

Figure 3 shows the amount of total traffic

(entering the site plus exiting the site)

generatedper1,000squarefeetofbuildingat

each site during the evening rush hour (the

busiest

60

minute

period

between

4:00

and

6:00 p.m.). The highest rate observed in the

evening rush hour was 1.32 trips per 1,000

square feet while the lowest was 0.50 trips

per 1,000 square feet. The average trip rate

was0.94tripsper1,000squarefeet,which is

alsoa37%reductionintripscomparedtothe

industry average rate of 1.49 documented in

the Institute of Transportation EngineersTripGeneration,8thEdition.All six sites have a ratelowerthanindustryaverage.The

economy

was

performing

poorly

during

the

fall

of

2009

when

the

data

was

collected.

It

is

possiblethatthereportedoccupancyrateswereincorrectoremployeesweregivenlargerthan

normalworkingspaces. Amoreconsistentwayofcomparingtrafficgeneration istocompare

theamountoftrafficgeneratedbyemployee,sincetheemployeevariableismoreindependent

fromtheconditionoftheeconomy.

0

0.5

1

1.5

2

A B C D E F Avg

Figure2 AMPeakHour

Tripsper1,000sf

0

0.5

1

1.5

2

A B C D E F Avg

Figure3 PMPeakHour

Tripsper1,000sf

Normal Office = 1.49



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Figure4showstheamountoftotaltraffic(enteringthesiteplusexitingthesite)generatedper

employeeateachsiteduringthemorningrushhour(thebusiest60minuteperiodbetween7:00

and9:00a.m.). Thehighestrateobservedinthemorningrushhourwas0.60tripsperemployee

while the lowest was 0.24 trips per employee. The average trip rate was 0.35 trips per

employee, which is a 27% reduction in trips compared to the industry average rate of 0.48

documentedintheInstituteofTransportation

EngineersTripGeneration,8thEdition. Fiveofthe six sites have a rate lower than industry

average. The0.60tripsperemployeeatSite

Aisanunexplainedanomalyinthedata. The

building is a LEED certified headquarters

buildingforanenergycompany. Itispossible

they had a meeting with field staff the

morningthedatawascollectedortheywere

giving a tour of the building, which they

regularly do. The building manager has not

corroboratedeitherofthesetheories.

Figure 5 shows the amount of total traffic

(entering the site plus exiting the site)

generated per employee at each site during

theeveningrushhour(thebusiest60minute

period between 4:00 and 6:00 p.m.). The

highest rate observed in the evening rush

hour was 0.39 trips per employee while the

lowest was 0.27 trips per employee. The

averagetripratewas0.31tripsperemployee,

which is also a 33% reduction in trips

compared

to

the

industry

average

rate

of

0.46

documentedintheInstituteofTransportation

EngineersTripGeneration,8thEdition.Allsixsiteshavearatelowerthanindustryaverage.ParkingGeneration

Figure6showsthepeaknumberofparkingstallsfilledper1,000squarefeetofbuildingduring

the study periods. The highest rate observed was3.22 stallsper 1,000 square feet while the

lowest was 1.20 stalls per 1,000 square feet

ofbuilding. Theaveragepeakoccupiedstall

rate was 2.23 stalls per 1,000 square feet,

which is a 21% reduction in stalls compared

to the industry average rate of 2.84

documented

in

the

Institute

of

Transportation Engineers ParkingGeneration, 3rd Edition. Five of the six siteshavearatelowerthanindustryaverage. We

do not have a hypothesis for why the peak

rate at Site C was slightly higher than the

industry standard average. Note the rate

00.10.20.30.40.50.60.7

A B C D E F Avg

Figure4 AMPeakHour

TripsperEmployee


00.10.20.30.40.50.60.7

A B C D E F Avg

Figure5 PMPeakHour

TripsperEmployee


00.5

11.5

22.5

33.5

A B C D E F Avg

Figure6 PeakParked

Stallsper1,000sf



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11

Findings Related to OfficeBuildings with TDM:

30%ReductioninTraffic

Generation

10%Reductionin

RequiredParkingStalls

from Parking Generation is the peak rate for the day and encompasses suburban officebuildings.

Figure 7 shows the peak number of parking stalls filled per employee at each site during the

study periods. The highest rate observed was0.92stalls per employeewhile the lowest was

0.61 stallsperemployee. Theaveragepeak occupied stall rate was0.74stalls peremployee,

which isan11%reduction installscomparedto the industry average rate of 0.83

documented in the Institute of

Transportation Engineers ParkingGeneration, 3rd Edition. The higher thanaverage parking rate for Site A in Figure 7

may have been caused by a field staff

meetingorfacilitytourthemorningthedata

wascollected. Thebuildingmanagerhasnot

corroboratedeitherofthesetheories. Note

theratefromParkingGeneration isthepeakrate

for

the

day

and

does

not

distinguish

betweenurbanandsuburbanlocations.

Conclusions

Overall, TDM plans do appear to have a positive effect on traffic generation and parking

numbersinbuildingswithTDMplansinplacewhencomparedtotheInstituteofTransportation

Engineers published standards. Based on the analysis performed for this study, on average,

TDMplansreducetrafficgenerationratesby27%to37%andparkinggenerationfrom11%to

21%dependingonthetimeofdayandothervariables.

IfofficebuildingsimplementathoroughTDMplan,theywill

generate less peak hour traffic and require fewer parking

stalls. Werecommendpractitionersusea30%reductionin

traffic generation (compared with the Institute of

Transportation Engineers standard rates) when assessing

the traffic impacts of a proposed office building that will

implementaTDMplan. Werecommendpractitionersusea

10% reduction in parking stall requirements (compared

with the Institute of Transportation Engineers standard rates) for office building that will

implementaTDMplan.

Thesearesignificantfindings. Thereductionintrafficgenerationcouldoftenbethedifference

between needing to install a traffic signal or not, typically a $200,000 expenditure. In

Minnesota,asurfaceparkingstallcostsbetween$3,000and$4,000 tobuildwhileastall ina

parkingrampcostsbetween$15,000and$20,000. Thismeansthe181,000squarefootoffice

labeled Site B could have built 245 parking stalls instead of 270 stalls, saving $75,000 to

$100,000 in construction costs. This does not factor in lower maintenance costs, lower

0

0.2

0.4

0.6

0.8

1

A B C D E F Avg

Figure7 PeakParked

StallsperEmployee



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12

environmental impacts, or the higher employee satisfaction benefits Travel Demand

Managementprovides.

NextSteps

ThisstudyanalyzedtheeffectivenessofTDMstrategiesatsixsites inMinnesota. Ourfindings

areencouraging,butmuchmoredatashouldbecollectedaroundtheUnitedStates. Duetothe

limiteddataset,wewerenotabletodetermineTDMbestpracticeswhichcouldbeidentified

withalargerdataset. Theuniversalityofourfindingscouldalsobecorroboratedwithdatafrom

differentregionsofthecountry.

Acknowledgements

Thankyou to Marc Culver, Mike Anderson, Melissa Madison, Randy Newton, Damien Goebel,

andCathy

Moeger

who

were

very

helpful

in

assisting

us

in

selecting

sites

for

our

study.

Huge

thanksalsogoestotheMinnesotaPollutionControlAgencyDepartmentofNaturalResources

HumanServicescomplexandColoplastfortheirassistance. Werespectthewishesoftheother

companieswhowishtoremainanonymous,butwegreatlyappreciatetheirassistanceaswell.

AbouttheAuthors

DuringtheperiodofJuly,2009January,2010agroupofprofessionals(civilengineers,landscape

architects,andurbanplanners)tookpartinanapprenticeshipunderthetutelageofMikeSpack,

president and founder of Spack Consulting. The apprentices were Mike Bultman, Joe Collins,

KirkPettis,

and

Jenni

Thompson.

This

Travel

Demand

Management

study

was

prepared

as

part

oftheapprenticeshipprogram.

Documents

Travel Demand Management Effectiveness Report