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Regional Bicycle Demand Model: In Use Today in Portland. Bill Stein, Metro. TRB Transportation Applications Conference Reno, Nevada – May 9, 2011. Presentation overview. Attributes of Portland’s regional bicycle network Reasons for and features of our bicycle model
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Regional Bicycle Demand Model:In Use Today in Portland Bill Stein, Metro TRB Transportation Applications Conference Reno, Nevada – May 9, 2011
Presentation overview • Attributes of Portland’s regional bicycle network • Reasons for and features of our bicycle model • Bicycle utility incorporated into regional model • Bicycle path choice / assignment • Next steps
Bicycle boulevards • Low-volume, low-speed streets optimized for bike travel • Treatments include traffic calming/diversion, signage and pavement markings, and intersection controls • Through movements for bikes prioritized over other modes
The problem • Portland policymakers have great interest in learning what types of projects will increase bicycling. • For most trip purposes, our previous regional model used only distance as the factor influencing bike mode choice. • A tool was sought for evaluating impacts of future bike projects on mode share and route choice.
Project support • Portland State University • 2007 GPS survey of bicyclists’ route choices • Dr. Jennifer Dill • Development of bicycle route choice model • Dr. John Gliebe, Joe Broach • PTV America • Software support • Chetan Joshi
What our bike model does • Models bicycle travel on all streets—plus multi-use paths—in the Portland-Vancouver metro area • Path choice is based on full origin-to-destination consideration (not link-to-link) • example: percent of route on bicycle boulevard • Bicycle utilities feed into regional demand model • Robust bicycle assignments, with multiple display options • Models 24-hour average weekday bicycle flows
Special considerations • The model currently runs on “satellite” bicycle networks which took substantial effort to build • The model is only as good as our validation data • Run time is not trivial: millions of paths are individually analyzed several times • Bicycle-transit interactions are not addressed • Path choices are based on route preferences of current bicyclists
Bicycle utilities in mode choice equations • Commute (HBW + College) • Mode-specific constant • Coefficients on distance and land use mix • With bike model: coefficient on bicycle utility • Non-commute (all other purposes) • Mode-specific constant • Coefficient on distance • With bike model: coefficient on bicycle utility
Variables affecting bicycle utility • Proportion of route on off-street paths, bike boulevards, bike lanes • Proportion of route on links with grade > 2% • Turns, traffic signals, stop signs per mile • Traffic volumes of on-street travel and opposing links at left turns • Bridge bike facility type • Distance • Commute or non-commute trip
Bicycle utility & distance coefficients • Bicycle utility coefficient • Bicycle distance coefficient
Bicycle model application • Skim creation • Route search based on impedance function • Returns single, best utility path between zones • Demand model • Bicycle utility added to mode choice equations • Assignment • Generates up to nine alternative routes per zone pair based on path utilities • Optimum paths are determined using a stochastic assignment process
2007 modeled bicycle commute flows westbound on the Hawthorne Bridge
Next steps • Through mid-summer 2011: further testing of model (validation and sensitivity tests) • Beginning late summer: model will be available for RTP, MTIP, air quality, and corridor projects • Mode choice parameters will be updated when 2011 household travel survey data are available
Questions? Bill Stein Metro 503-797-1855 Bill.Stein@OregonMetro.gov