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 October 2006, the Texas Department of Transportation (TXDOT) deployed an ITS work zone system on I-35 south of Waco in Hillsboro County. This section of I-35 is a rural area with a large number of through trips and drivers unfamiliar with the area. The main goals of the system were to provide motorists with real-time information on downstream conditions and to provide alternate route guidance during times of heavy mainline congestion due to incidents or construction. In this case, the approaches to the work zone were on three different roadways, therefore TXDOT deployed a comprehensive work zone traffic management solution that consisted of three independent traffic monitoring systems. System components included portable, solar-powered dynamic message signs and system detection, video cameras, and web services for both the public and TXDOT staff.
Traffic data collection efforts focused on measuring diversion rates at the freeway exit ramps to test driver response to the system. Data were also collected at three key diversion routes along the corridor that provided access to the signed alternate routes. Data were archived from October 3, 2006 through February 4, 2007 and analysis was performed before and after the system was active.
The analysis showed that during times of very heavy congestion, large percentages of motorists would follow the diversion routes posted on the dynamic message signs. Major incidents and heavy construction activity were the main reasons for traffic diversion. The system diverted an average of 10 percent of mainline traffic to alternate routes, with diversions as high as 28 percent.
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