Auto Ownership Model
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Auto Ownership Model For Southeast Florida Models Southeast Florida FSUTMS Users Group Meeting Ft. Lauderdale, FL. Why?. Life Style Gen Requires Number of HHs At each auto ownership level (0, 1, 2, 3+) For HH with and HH without children Current model input is:

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Why

Auto Ownership ModelFor Southeast Florida ModelsSoutheast Florida FSUTMS Users Group MeetingFt. Lauderdale, FL

Corradino


Why

Why?

  • Life Style Gen Requires Number of HHs

    • At each auto ownership level (0, 1, 2, 3+)

    • For HH with and HH without children

  • Current model input is:

    • Vehicles in HH’s with children

    • Vehicles in HH’s without children

    • Disaggregated by a series of polynomials

  • Lack of consistent and logical forecasting methodology

    • Most models either grow vehicles in proportion to HH’s, or

    • Perhaps adjust to meet county aggregate total

Corradino


Past work

Past Work

  • For District 4 – Paper by Li, Ewing & Gross (late 1990’s?).

  • Other major urbanized areas throughout the US.

  • Encouraged by USDOT

  • Most models use some combination of:

    • Persons

    • Workers

    • Density

    • Children

    • Income – Almost all require this one ****

    • Accessibility

Corradino


Since fsutms doesn t use income and previous work required income

Since FSUTMS Doesn’t Use Incomeand Previous Work Required Income

  • Use

    • Persons/HH

    • Workers/HH

    • Children

      • With

      • Without

    • Density (HH, Emp, Area)

    • Accessibility (Time & Trip Attractions)

Corradino


Model form

Model Form

Multinomial Logit

Sx = Exp(ux)/[Exp(u0)+ Exp(u1)+ Exp(u2)+ Exp(u3)]

Where

Sx = share of HH’s at each auto ownership level (0,1,2,3)

ux = utility for level x

=f(persons or workers/HH, density, accessibility)

Corradino


Density calculation

Density Calculation

Density = (Households + Total Employment)/(net area)

Corradino


Accessibility calculation

Accessibility Calculation

  • Inputs

    • Travel Time Skim Matrix (for GM)

    • Trip Attractions (from “trial” Gen run)

    • Friction factors

  • For each TAZ:

    Accessibility=

    Sum of: FF(t)*Attractions for each purpose

    Over all destinations

Corradino


Best model

Best Model

  • Households without children

    • Persons

    • Density

    • Accessibility

  • Rho-squared: 0.342683

Corradino


Best model1

Best Model

  • Households with children

    • Workers

    • Density

    • Accessibility

  • Rho-squared: 0.288637

Corradino


Other notes

Other Notes

  • Gross and Ewing found a rho-squared of 0.4704 for their model 4.

  • For the 0, 1, 2+ models, comparable to Gross and Ewing, our models have rho-squared of 0.39 and 0.50 for without and with children respectively. These models are at least as well as Gross and Ewing.

  • For the 0, 1, 2, and 3+ models, the proposed models have rho-squared of 0.34 and 0.29 for without and with children respectively. These are still good models, but as expected, the task is more difficult when trying to estimate 4 levels.

  • The signs in all models are correct, and all variables included in the equations are significant at the 0.05 level and beyond for most variables.

Corradino


Remaining work

Remaining Work

  • County Biases will be tested

  • Life-Style Gen will have to be modified to use the new model

  • Actual model implemented in Matrix

Corradino


Questions

Questions?

Corradino


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