In 2003, the Federal Highway Administration (FHWA) began the Work Zone Mobility and Delay Reporting Assessment to document the tangible benefits of using ITS in work zones in a quantitative way. The purpose of the study was to highlight "before and after" analyses that quantify the mobility and safety benefits of using ITS applications for work zone traffic management. The study intended to increase the knowledge and promote further use of deploying ITS solutions for work zone management.
The study analyzed data from five sites:
- District of Columbia
- North Carolina
These sites were selected because the construction project showed significant potential to have a measurable impact on traffic conditions, creating a situation where ITS could be used to reduce the impact.
In 2006, the District of Columbia Department of Transportation (DDOT) deployed an ITS work zone system on I-295 during construction of approximately seven miles of roadway. The main goals of the system were to monitor conditions and improve mobility and safety through the work zone. The system incorporated a real-time information system for motorists and via a Web site. System components included, dynamic message signs, speed sensors, system detection and video cameras.
Traffic data were collected and archived from installed system detectors for nine months prior to and during construction. Historical data were used to establish a baseline prior to system implementation. Sensor data and observations were used as data sources for analysis. Traffic queues, volumes and diversion patterns were analyzed as methods of performance measurement.
The real-time information system deployed on I-295 appeared to effectively divert traffic to unsigned, unspecified alternate routes during times of significant congestion. One analysis performed on two similar Tuesdays, one before construction and one after, found the volume levels were almost exactly the same with the exception of the time period from approximately 10 AM until 1 PM when the system posted delay information and recommended that motorists seek an alternate route. During this time period the data showed a 3 to 89 percent decrease in mainline volumes, with an average of 52 percent decrease in delay. These results show that the system likely reduced delay substantially for motorists by providing information to better enable them to choose an alternate route.
These results are also found in the document - Benefits of Using Intelligent Transportation Systems in Work Zones: A Summary Report, Federal Highway Administration, April 2008. http://ops.fhwa.dot.gov/wz/its/wz_its_benefits_summ/index.htm