Suggested Citation:
Passmore, Reid, Kari Watkins, Randall L. Guensler (2024)

BikewaySim: Using Changes in Revealed Impedance to Assess Potential Benefits of New Cycling Infrastructure 

This research proposes a framework for assessing the impacts of new and existing cycling infrastructure using minimum impedance routing. Impedance represents the relative difficulty of cycling taking into consideration travel time, exposure to automobiles, hills, and the provision of cycling infrastructure. An all-paths network is created from OpenStreetMap data, and data on traffic volumes, vehicle speeds, the number of vehicle lanes, elevation, and bicycle facilities are reconciled with the all-paths network. Map-matched cycling GPS traces from the CycleAtlanta app are cleaned and then used to calibrate link and turn impedance functions that consider cyclists’ preferences for link and turn attributes. The calibration process uses stochastic optimization techniques to maximize the overlap between the map-matched and impedance paths. The calibrated link and turn impedance functions are then applied to the 250 square mile metro Atlanta study area to assess the impact of 38 planned bicycle facilities for 3.6 million trips from the Atlanta Regional Commission Activity Based Model. Both the minimum travel time and impedance paths are calculated for the existing network and compared against the minimum impedance paths for the future network with the planned bicycle facilities. The results were then processed to create metrics and visuals on trip impedance reduction, percent detour, change in link betweenness centrality, impedance reduction contribution, and bikesheds. The calibrated impedance factors and framework are then applied to Savannah, GA to assess the impacts of 57 proposed bicycle facilities. This demonstrated that the framework and calibrated impedance factors could likely be used throughout the state of Georgia to assist GDOT, MPOs, and cities in assessing and prioritizing cycling infrastructure projects.