Displaying Simulation Results

To visually display simulation results, the AMS team generated space-time plots showing the speed of traffic along a route as a function of position and time. Two plots are shown side by side: one for the westbound arterial on the left, and one for the westbound freeway on the right.

In these contour plots:

  • Traffic flows from bottom to top (position is indicated on the vertical axis), and time evolves from left to right (time of day is indicated on the horizontal axis).
  • The color indicates the speed of traffic. High speed is represented in green for the freeway and in yellow for the arterial. Slow speeds (i.e., congestion) is indicated in red. Technically, each color represents a specific speed, as indicated by the colorbar next to each plot (units in miles per hour).
   Show me how a contour plot is constructed from traffic measurements.

The simulations gave the team confidence that the model works as expected. Both arterial and freeway traffic are modeled together in a CTM framework. The model generates incident congestion and recurrent congestion appropriate to the changes in inputs.

From the results of the simulations (a common incident type, with and without intervention), the team was able to calculate vehicle hours traveled (VHT) and vehicle miles traveled (VMT) under the simulated circumstances and thus gauge the impact of both the incident and the intervention on corridor performance.

Detailed simulation results can be found in the AMS Phase 1 Report.