Alan J. Horowitz
University of Wisconsin, Milwaukee
About the research
This is an evaluation of the Travel Time Prediction System (TIPS), a portable automated system for predicting and displaying travel time for motorists in advance of and through work zones, on a real-time basis. Information is displayed on several Changeable Message Signs (CMS).
The system was deployed along I-94 in two Counties in Wisconsin, in advance of a construction zone. The evaluation measured TIPS ability to accurately predict travel times through the construction zone, and the systems impact on trip diversions.
A comparison of Actual and TIPS-estimated travel times based on 210 travel time runs indicated 2-3 minute differences on average; the percentage of Actual travel times within +/-4 minutes of TIPS times was 46% and 66% for each of two evaluated CMS. Predicted travel times were within 30% of Actual travel times for 85% and 86% of the analyzed observations. The evaluated system performed reliably throughout the data collection hours, with a minor exception.
The injury crash frequency for the TIPS work zone was lower after TIPS began operation than for a similar construction zone in the opposite direction of travel-results should not be viewed as conclusive.
Modest trip diversion changes were identified, during the period TIPS was operational, when displayed travel times exceeded their median value.
Vendor: PDP Associates