As part of a pavement rehabilitation project on I-64, the Traffic Information and Prediction System (TIPS) was installed as a means of providing real-time data for motorists in advance and through the work zone. This system collects real-time data using roadside non-contact (microwave) sensors, processes the data in a personal computer, calculates travel time between different points on the roadway, and displays the travel time information on several portable changeable message signs positioned at pre-determined locations along the roadway. The system displays information in the form of travel time and distance through the work zone. The objective of this report was to document the performance of TIPS as a method to provide accurate and current information to drivers as they travel through a work zone.
The primary components of the evaluation included the following: 1) the performance and reliability of TIPS, 2) the accuracy of travel time estimates, 3) diversion of traffic from I-64 to an adjacent route, 4) crash data during construction and 5) opinions of drivers who had just traveled through the work zone.
Although problems with reliability and accuracy were encountered, TIPS was shown to have the potential to provide current information to drivers traveling through work zones. However, for the system to be effective, several changes from the methodology used in this project should be made. Suggestions include:
- Installation and maintenance of TIPS should be assigned to the prime contractor or an on-site subcontractor with the responsibility to monitor and make any changes in a timely manner.
- The TIPS logic and software should provide for automatic detection and notification of problems.
- Provisions for variable message signs should be the responsibility of the TIPS contractor.
- Use of this type of system would be more effective at construction sites that did not involve numerous changes in lane closure locations as occurred at this project.
- Providing real-time information would be more effective if delay time and a potential alternative route could be offered to motorists.
There was a slight increase in crashes in the construction zone compared to previous years. This increase was due to rear-end crashes related to congestion. There was an increase in traffic volume on the parallel route (US 60) that appeared to be related to local drivers not using the interstate. Interviews with drivers found that they observed and understood the signs but questioned the usefulness of the information provided. Although the average difference between the actual and displayed travel times was not high, there were instances where this difference was substantial. The correlation between the actual and predicted times became worse at the signs closest to the work zone.
A general specification was included for future applications of real-time traveler information systems in work zones.
Digital Object Identifier
Pigman, Jerry G. and Agent, Kenneth R., "Evaluation of Traffic Information and Prediction System (TIPS) as Work Zone Traffic Control" (2004). Kentucky Transportation Center Research Report. 212.