Trip Generation at Mixed-Use Developments December 19, 2012 Jerry - - PDF document

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Trip Generation at Mixed-Use Developments December 19, 2012 Jerry - - PDF document

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12/27/2012 Trip Generation at Mixed-Use Developments December 19, 2012 Jerry Walters Fehr & Peers EPA MXD 1 12/27/2012 D Factors that Affect Trip Generation 1. Density dwellings, jobs per acre 2. Diversity mix of housing,

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12/27/2012 1

Trip Generation at Mixed-Use Developments

December 19, 2012 Jerry Walters ◊ Fehr & Peers

EPA MXD

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12/27/2012 2 1. Density dwellings, jobs per acre 2. Diversity mix of housing, jobs, retail 3. Design connectivity, walkability 4. Destinations regional accessibility 5. Distance to Transit rail proximity 6. Development Scale pop, jobs 7. Demographics household size, income

“D” Factors that Affect Trip Generation

1D

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12/27/2012 3 239 MXD: Seattle, Portland, Sacramento, Boston, Atlanta, Houston Validation: Northern and So. Cal, Texas, Georgia, Florida, Utah

Gateway Oaks, Sacramento River Place, Portland

EPA Nationwide Study of MXD Travel

  • Density of population and employment
  • Diversity: jobs/housing relative to regional balance
  • Diversity: balance of commercial, office, and public
  • Design: intersections per square mile
  • Destination Accessibility: jobs within 1 mile
  • Destination Accessibility: jobs within a 30 min by transit
  • Distance to Transit: rail station, bus stops within ¼ mile
  • Development Scale: MXD population and employment
  • Demographics: household size, vehicle ownership

* Internal travel and walking, transit use, trip length

7D Factors Correlated with Reduced Travel

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12/27/2012 4

27 Nationwide Validation Sites

  • 6 Florida sites

(including ITE Trip Generation Handbook)

  • 15 California sites
  • 2 sites in Texas
  • 2 in Georgia, S Carolina
  • 2 sites in Utah

Variety of scale, mix, design Atlantic Station, Atlanta Uptown District, San Diego

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12/27/2012 5 Irvine California Plano Texas Mixed-Use Centers, California and Florida

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12/27/2012 6 Celebration Florida Otay Ranch California South Davis, CA South Davis, California

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12/27/2012 7 Moraga, CA Mockingbird Station, Dallas Bay Street, Emeryville, CA

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MXD Model Validation

10 20 30 40 50 60 70 80 90 100 Site 1 Site 2 Site 3 Site 4 Site 5 Site 6 Site 7 Site 8 Site 9 Site 10 Site 11 Site 12 Site 13 Site 14 Site 15 Site 16 Site 17 Site 18 Site 19 Site 20 Site 21 Site 22 Site 23 Site 24 Site 25 Site 26 Site 27 Site 28

External Vehicle Trips (1000s)

Gross Trips Net Trips MXD Model Observed

Error Comparison: EPA MXD v. ITE Handbook

(27 Validation Sites)

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MXD Model Compared with ITE

10 20 30 40 50 60 70 80 90 100 20 40 60 80 100

Predicted Trips (1000s) Observed Trips (1000s)

ITE MXD

MXD Acceptance

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12/27/2012 10

NCHRP 684

NCHRP 684 Internalization Surveys

Development Percent Internal Capture AM Peak Period PM Peak Period At Trip Origin (Outbound Trips) At Trip Destination (Inbound Trips) At Trip Origin (Outbound Trips) At Trip Destination (Inbound Trips)

Mockingbird Station 31% 22% 36% 38% Atlantic Station 17 12 38 44 Legacy Town Center 11 15 37 33 Country Isles

  • 22

24 Village Commons

  • 9

9 Boca del Mar

  • 8

7

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NCHRP 684 Land Use Interactions

Origin Land Use Destination Land Use

1

Office Retail Restaurant Residential Cinema Hotel

Office

  • 20%

4% 2% 0% 0% Retail 2%

  • 29%

26% 4% 5% Restaurant 3% 41%

  • 18%

8% 7% Residential 4% 42% 21%

  • 0%

3% Cinema 2% 21% 31% 8%

  • 2%

Hotel 0% 16% 68% 2% 0%

  • Effect of Separation on Interaction
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12/27/2012 12

Error Comparison: NCHRP vs ITE Handbook

(3 Validation Sites)

Error Type Existing ITE Method NCHRP Method Explanation

Average error +26%

  • 4%

Average error for sum of all sites

Absolute average error 28% 17%

Average magnitude of error per site

Standard deviation 34% 20%

Expect two-thirds of site estimates within this error range

Integrated Method EPA MXD + NCHRP 684

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Optimal Blend of NCHRP 684 and EPA MXD

AM Peak PM Peak ADT NCHRP 684 10.1% 36.5% n/a EPA MXD 89.9% 63.5% 100%

The MXD+ Method for Estimating Traffic Generation of Lower-impact Development

  • 1. Apply the full EPA MXD method to predict external traffic generation as

influenced by site development scale, density, accessibility, walkability and transit availability, resident demographics and general mix of uses.

  • 2. Apply the full NCHRP 684 method to capture the effects of detailed land use

categories, including hotel and theater and restaurant, and the spatial separation of uses within small and medium sites.

  • 3. Combine the results of the two methods in terms of percentages of trips

remaining internal to the development site, using proportioning factors presented in the table above.

  • 4. Apply walking and transit adjustments to off-site travel using the EPA MXD

method.

  • 5. Discount standard ITE traffic generation rates by the percentages of

internalization produced in step 3 and the percentage of walk and transit travel in step 4 to obtain the estimate of site generated traffic.

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Comparison of Methods

Development, Validation, Acceptance

EPA MXD Method NCHRP 684 Method MXD

+

Method

Development of Method

Household surveys at 239 sites in Boston, Atlanta, Houston, Portland, Seattle, and Sacramento Traffic counts and interviews at 3 sites in Georgia and Texas Combined sources used for EPA MXD and NCHRP 684

Validation of Method

27 sites in CA, UT, TX, GA, FL, NC including all of the NCHRP 684 survey sites 7 sites, including 3 sites at which model development surveys were performed, plus 3 sites in Florida and one in N Carolina Combined sources, 27 sites, used for EPA MXD and NCHRP 684

Acceptance in Profession

ASCE Peer Review, SANDAG MPO and traffic engineers, and public and agency review of environmental documents in CA and WA. NCHRP review panel (New method)

Comparison of Methods

Project Characteristics Considered

EPA MXD Method NCHRP 684 Method MXD+ Method Density of Development   Diversity of Uses: Jobs/Housing    Diversity of Uses: Housing/Retail   Diversity of Uses: Jobs/Services   Diversity of Uses: Entertainment, Hotel   Design: Connectivity, Walkability    Design: Separation Among Uses   Destination Accessibility by Transit   Destination Accessibility by Walk/Bike   Distance from Transit Stop   Development Scale   Demographic Profile  

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Comparison of Methods

Performance at Validation Sites

EPA MXD Method NCHRP 684 Method MXD+ Method1 Daily Traffic Generation

R-squared 96%

  • 96%

Average Error 2%

  • 2%

Root Mean Square Error 17%

  • 17%

AM Peak Traffic Generation

R-squared 97% 93% 97% Average Error 12% 30% 12% Root Mean Square Error 21% 33% 21%

PM Peak Traffic Generation

R-squared 95% 81% 97% Average Error 8% 18% 4% Root Mean Square Error 18% 36% 15%

10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,000 90,000

Daily Traffic Generation Comparison of ITE Handbook and MXD+ Methods

ITE Handbook MXD+ (EPA) Traffic Count

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1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000

AM Peak Hour Traffic Generation Comparison of ITE Handbook and MXD+ Methods

ITE Handbook MXD+ Traffic Count 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000

PM Peak Hour Traffic Generation Comparison of ITE Handbook and MXD+ Methods

ITE Handbook MXD+ Traffic Count

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Trip Generation at Mixed-Use Developments

December 19, 2012 Jerry Walters ◊ Fehr & Peers