Automated Work-Zone Information System on Urban Freeway Rehabilitation: California Implementation

In October 2004, about 9 lane km of deteriorated truck lanes on Interstate 15 at Devore in Southern California was rebuilt during 18 days with extended one roadbed full-closures with the counterflow traffic system and 24-h construction operations. The project implemented the automated work zone information system (AWIS) to reduce peak hour delay during construction by changing road user’s travel patterns and diverting traffic to detour routes. This paper describes the design, performance, and validation of AWIS with monitored traffic data before and during construction used. The AWIS was installed to provide road users with real-time travel information so that they could avoid traffic delays in the construction work zone (CWZ) corridor. Travel times through the CWZ were estimated from speed data and enhanced in two ways: (a) portable and permanent changeable message signs on site and (b) off-site (project website) implementation with travel time messages, traffic snapshots, and video streaming. AWIS travel time was estimated at 90% of actual travel times as measured by probe vehicles. The peak hour traffic demand through the CWZ was reduced by up to 18%, with significant volume increases to detour freeways. The AWIS operation contributed to a decrease in the maximum delay for weekday peak hours (from expected 90 min to measured 50 min on average during construction). The outcome of this study will help transportation agencies and practitioners efficiently design and operate AWIS for highway rehabilitation under high traffic volume.