ASWS Speed Study

Analyzing the speed changes on the approach of the three high-speed intersection before and after the removal of advanced signal warning systems (ASWS)

Three intersections are equipped with advanced signal warning systems (ASWS) that warn upstream drivers to prepare to stop at the downstream intersection which is turning red. The ASWS are to be removed and this study is a comparative analysis on how speed changes on the approaches of the intersections as different phases of ASWS deconstruction. Round one is with the ASWS in full operations. Round two is with the ASWS as a passive flashing signal. Round 3 is when the ASWS does not flash. Finally, round four is with the ASWS completely removed.


For each round, the speed change at various locations along the two main street approaches of the intersections are extracted. The percentile speeds for each location is determined and the change in speed along the approach is determined. The data is also paired with the signal timing data to see how speeds change with changes in the signal status.