Trip Generation, Parking Generation and Transit-Oriented Development

Arlie AdkinsUC Berkeley

Metro TDM SymposiumLos Angeles

February 5, 2008

Outline

• Trip Generation

• What we already know

• New evidence

• Parking Generation

• New evidence

• Minimum parking requirements

• Preliminary results from nationwide survey

• Lessons

TOD and Travel BehaviorWhat We Already Know

TOD and Travel BehaviorWhat We Already Know

Source: Lund, Cervero, Wilson (2004)

TOD and Travel BehaviorWhat We Already Know

Source: Renne (2005)

Comparison of Shares of Transit Commuting Comparison of Shares of Transit Commuting in TODs versus Regions from 1970 in TODs versus Regions from 1970 -- 20002000

TODs maintained market shares while MSAswitnessed sharp declines

TOD and Travel BehaviorWhat We Already Know

35% higher  probability

Sensitivity Test: Car Ownership Covariate

Source: Lund, Cervero, Wilson (2004)

TOD and Travel Behavior ITE Trip and Parking Generation

• Called the “Bible” of traffic Impact analysis • Widely relied on, especially in smaller cities• Known suburban, car- oriented bias • Likely overstates auto traffic impacts of TODs

TOD and Travel BehaviorPutting the Issue in Context

Hypothetical 8 Acre Site

• 162 more units

• 20% density bonus

• $12 million saved in parking costs

• Increased transit ridership

• 801 units

• 100 units per acre

• 1762 parking spaces

• $33.3 million in parking capital costs

2.2

Park

ing

Spac

es p

er U

nit

• 963 units

• 120 units per acre

• 1058 parking spaces

• $21.3 million in parking capital costs

1.1

Park

ing

Spac

e pe

r Uni

t

Source: TCRP Report 128

TOD and Trip Generation New Evidence: TCRP Report 128

• Gauges TOD trip generation over-estimation

• Inform ITE Trip Generation Manual with adjustments for transit proximity

• Results presented in similar format to ITE

• 17 sites across 4 regions

TOD and Trip Generation New Evidence: TCRP Report 128

TODVeh. Trips

per DU (24 hr.)

ITE Rate

(24 hr.)

% point differencefrom ITE

Rate

Center Com. 4.79 6.72 -28.7%

Collins Cir. 0.88 6.72 -86.9%

Gresham Cen. 5.91 6.72 -12.1%

Merrick Apts. 2.01 6.72 -70.2%

Quatama Cr. 6.34 6.72 -5.6%

Mean 3.99 -- -40.7%

Std. Dev. 2.42 -- 36.1%

Metro Portland Trip Generation

TOD and Trip GenerationNew Evidence: TCRP Report 128

TODVeh.

Trips per DU

(24 hr.)

ITE Rate

(24 hr.)

% point differencefrom ITE

Rate

Mission Wells 3.21 6.72 -52.2%Montelena 2.46 6.72 -63.4%

Park Regency 5.01 6.72 -25.4%Verandas 3.10 6.72 -53.8%

Wayside Com. 3.26 5.86 -44.3%Mean 3.41 -- -47.8%

Std. Dev. 0.95 -- 14.3%

•24 Hours: 44% fewer trips

•AM Peak: 49% fewer trips

•PM Peak: 48% fewer trips

TOD and Trip GenerationNew Evidence: TCRP Report 128

TOD and Trip GenerationNew Evidence: TCRP Report 128

Scatterplot of PM Trip Generation Rate to ITE Rate with Residential Densities

TOD and Trip GenerationNew Evidence: TCRP Report 128

Scatterplot of PM Trip Generation Rate to ITE Rate with Distance to CBD

20 units/acre

5 units/acre

Influence of Residential Densities & Distance to CBD

TOD and Trip GenerationNew Evidence: TCRP Report 128

TOD and Travel BehaviorParking Generation

But What About Parking?

Parking, Trip Generation and TODParking Generation: New Evidence

• Empirical study of parking generation

• 31 sites in Bay Area and Portland

• Peak and off-peak counts at each site

• Multiple sites in some station areas capture wide variation

TOD and Travel BehaviorParking Generation: New Evidence

SiteObserved Parking

Generation

Differencefrom ITE

Rate

Gateway Station

Gateway Terrace 0.53 -56%

Gateway Park Apts. 0.82 -32%

E 148th Ave Station

Rachel Anne 0.88 -26%

Dalton Park 1.17 -3%

E 162nd Ave StationSequoia Park 0.79 -34%

Morgan Place 0.65 -46%

Gresham Central Station

Gresham Central 1.00 -17%

Mean 1.08 -11%Standard Deviation 0.24 20%

Site Observed Parking

Generation

Difference from ITE

Rate

Beaverton Creek Station

Center Pointe 1.23 3%

Elmonica Station

Elmonica Court 0.90 -25%

Cambridge Crssng. 1.05 -13%

Willow Creek

Wyndhaven 0.90 -25%

Quatama Station

Briarcreek 1.12 -7%

Quatama Crossing 1.32 10%

Quatama Village 1.37 14%

Orenco Station

Orenco Gardens 0.76 -37%

Portland Parking Generation: Preliminary Results

TOD and Travel BehaviorParking Generation: New Evidence

Site Observed Parking Generation % different from ITE Rate

Walnut Creek: Pleasant Hill BART Station

Diablo Oaks 0.74 -38%

Arch. Walnut Creek 0.92 -23%

Park Regency 1.06 -12%

Arch. Walnut Creek Stat. 1.09 -9%

Villa Montanaro 1.23 -3%

Iron Horse Park 1.48 23%

San Leandro: Bayfair BART StationThe Hamlet 1.07 -11%

Union City BART StationThe Verandas 1.11 -7%

Parkside 1.13 -6%

Fremont BART StationPresidio 1.23 -3%

Watermark Place 1.27 5%

Mission Peaks 1.35 12%

Archstone Fremont 1.45 21%

Sun Pointe Village 1.47 23%

Park Vista Apartments 1.48 24%

Alborada Apartments 1.69 41%

Mean 1.22 2%Standard Deviation 0.24 20%

Bay Area Parking Generation:Preliminary Results

TOD and Travel BehaviorParking Generation: New Evidence

FremontBART

TOD and Travel BehaviorParking Generation: New Evidence

• Preliminary results show that peak parking generation increases by about .38 each half mile walking distance from the station

Given this number:

• A hypothetical 400-unit apartment complex built immediately adjacent to a rail station would need about 328 spaces

• A 400-unit complex 1 mile from the station would need 632 spaces

That’s a potential savings of as much as 3 acres!

Preliminary Results

TOD and Travel BehaviorParking Generation: New Evidence

• Very few sites in study would support a car free lifestyle

• People might commute to work by train, other trips still require a car

• Further analysis may shed light on this

• Clearly car storage occurring

ITE Overestimates

Preliminary Results

TOD and Travel BehaviorParking Generation: New Evidence

Sensitivity Test: Car Ownership Covariate

TOD and Travel BehaviorParking Generation: Lessons

A Natural Marriage: TOD & Carsharing?A Natural Marriage: TOD & Carsharing?

Work/School

Shopping

Pers. BusinessMedical

Social-Rec

Other

Trip Purposes• 30% car-shedding (2001-2005)

• Mean VMT Reduction of 12% (2001-2005)

• Unfortunately carshare vehicles rare in suburban station areas

R. Cervero, A. Golub & B. Nee,(2007) San Francisco City CarShare: Longer-Term Travel-Demand Trends and Car Ownership Impacts, Transp. Res. Rec. 1992,, pp. 70-80.

• Nationwide Survey of every city with a rail transit station

• 35% response rate (40% of cities over 100,000)

• Concentrations of 10 or more responses in Los Angeles, Bay Area, Chicago, and Washington-Boston corridor

TOD and Travel BehaviorMinimum Parking Requirements

• Allowable Grounds for Variances to Minimum Parking Requi

TOD and Travel BehaviorMinimum Parking Requirements

Key findings:

•96% of cities surveyed have minimum off street parking requirements for multi-family housing

• 86% percent of these cities allow for variances to these requirements

•Average maximum variance allowed for rail station proximity: 24%

Preliminary Results

• How receptive do you think elected officials in your city would be to lowering minimum parking requirements?

•

TOD and Travel BehaviorMinimum Parking Requirements

In GeneralWithin Walk of

Rail Station

Preliminary Results

• Walkable, bikable neighborhoods

• Nearby services - including grocery stores and high quality school

• Access to a true transit network

• Carshare

TOD and Travel BehaviorLessons: Think Holistically

Train Station + Housing ≠ TOD

• However...

TOD and Travel BehaviorLessons: Focus on Improving People’s Lives

• Global climate change is a strong policy and political driver

• Voters are paying attention

Photos credit: Flickr user Atwater Village Newbie

Photos credit: California High Speed Rail

TOD and Travel BehaviorLessons: Focus on Improving People’s Lives

... a word of caution

• Efforts to reconfigure our transportation systems and our cities must be rooted in improving people’s lives if they are to be politically sustained

• Historically, this has been the root of major urban transformations (e.g. post-war suburbanization)

• Makes our jobs easier and more rewardingPhotos credit: Flickr user Atwater Village Newbie

Photos credit: California High Speed Rail

•Conventional high frequency bus routes often overlooked in TOD discussion

• Bus lines generally carry the bulk of transit riders in a region

•More research is needed on the relationship between bus and TOD

TOD and Travel BehaviorLessons: Bus Networks and TOD

Los Angeles Bay Area Portland

Source: LA Metro; MTC; TriMet

TOD and Travel BehaviorLessons: Bus Networks and TOD

Metro Rapid(Los Angeles)

Frequent Service (Portland)

TOD and Travel BehaviorLessons: Bus Networks and TOD

Examples of recent bus TOD in Portland

Photos credited to developers

TOD and Travel BehaviorThank You!

• Thank you! And keep up the good work.

• Please let me know if you’re interested

• in seeing our final parking generation analysis

• or results from the parking survey.

• Arlie Adkins

• Arlie@Berkeley.edu