Traffic Simulation


We recently teamed up with some colleagues at Kittelson Associates for a demo project to test the compatibility of SketchUp and PTV Vissim—a multi-modal traffic flow simulation software. Vissim is a powerful tool that allows traffic engineers to evaluate road designs with traffic visualizations based on behavior profiles of each traffic element: drivers, pedestrians and bicyclists. The visualizations are typically comprised of 3d traffic moving on top of a 2d satellite image. Having seen a couple examples of Vissim simulations running through a SketchUp model (like this one...with dolphins!), we wanted to see what it would take to make one of our own. We chose to investigate how a two-way cycle track might perform on SW Broadway in downtown Portland. Here's a view of the existing conditions, which feature a standard door-zone bike lane:


And here is how the traffic simulation looks, running over a model featuring a two-way cycle track:

A few notes on the simulation: 1. No vehicle turning movements or parking maneuvers were simulated for simplicity's sake. 2. Bike volume was estimated at twice current volume to account for additional demand with the enhanced facility. 3. Animation is recorded at double speed.

Ady Leverette was a designer and a principal at Fat Pencil Studio between 2011 and 2018.