Effectiveness of End-of-Queue Warning Systems and Portable Rumble Strips on Lane Closure Crashes

The Texas Department of Transportation (TxDOT) has been deploying work zone intelligent transportation systems (ITS) in an effort to reduce the number of work zone crashes along the Interstate 35 (I-35) corridor. Road construction lane closures on I-35 are typically performed at night when traffic volumes are lower but driver awareness is often reduced. The two systems evaluated were temporary portable rumble strips (TPRS) alone and end-of-queue warning systems (EOQWS) combined with TPRS. The EOQWS consist of portable changeable message signs linked to radar speed sensors to proactively warn drivers of queueing and slowed conditions ahead. The TPRS alone were deployed for work zone lane closures where no queues were expected, and both EOQWS and TPRS were deployed for lane closures expected to cause queueing. The effectiveness of these systems was evaluated over 4 years of deployments and compared to 1 year of no deployments. Both TPRS alone and EOQWS with TPRS were found to cause a significant reduction in the number of crashes under queued conditions, 60 and 53%, respectively. Additionally, the severity of the crashes that did occur was significantly reduced under queued conditions when either treatment was in place. (C) 2017 American Society of Civil Engineers.