FRT 238: Evaluation of KYTC's Portable Queue Warning Alert System (PQWAS)

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Abstract FRT 238, Evaluation of KYTC’s Portable Queue Warning Alert System (PQWAS) One of the most dangerous places in a construction zone is prior to the work area where traffic must significantly slow down or come to an abrupt stop. This end-of-queue area is where motorists are at high-risk for a crash. In 2021, there were 1,247 crashes in work zones in Kentucky, and these crashes resulted in 299 injuries and 7 fatalities. There is a clear need to make the end of the queue safer for motorists. Kentucky has implemented a portable queue warning alert system (PQWAS) meant to address the problem of end-of-queue crashes in work zones. The Kentucky Transportation Cabinet (KYTC) has found that although the technology is beneficial in many situations, it may not be needed in all work zones. The technology adds a significant amount of cost to construction projects, and KYTC would like to better understand the benefits of the system and the best use cases for it. Kentucky first piloted the PQWAS about seven or eight years ago. In the last four to five years, the system has become more widespread in its use. In 2021, 16 construction projects utilized PQWAS, and in 2022, 21 projects utilized the system. Recently, the State Highway Engineer’s Office has mandated the use of PQWAS on all construction projects on Kentucky’s interstates and parkways. The PQWAS is intended to improve drivers’ awareness of the potentially dangerous situation at the end of the traffic queue. The primary system utilizes radar detection and/or crowdsourcing data to determine the speeds of oncoming traffic. Based on the speed data, the smart message boards are automatically updated with the appropriate messages. For added safety, a queue protection vehicle may also be deployed as part of the PQWAS. The queue protection vehicle is a large truck with a crash cushion, hazard lighting package, and message board. The vehicle moves down the shoulder toward oncoming traffic as needed to alert motorists to stopped traffic ahead. The construction contractor is responsible for implementing the PQWAS, but the KYTC Project Engineer provides directions on its use as needed. There are two primary objectives of this evaluation. The first objective is to measure the safety effectiveness of the technology. Specifically, researchers will consider the impact of PQWAS on crashes, injuries, and fatalities in the end-of-queue area. The second objective is to provide KYTC with guidance or best practices on the use and implementation of PQWAS. Some of the questions to address include: • How much crowdsourcing data is needed for this method to be effective (over the use of radar detectors)? • Where in Kentucky should radar, detectors be utilized over crowdsource data and vice versa?
Effective start/end date4/1/234/30/25


  • KY Transportation Cabinet: $188,685.00


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