Reducing upstream end-of-queue crashes at work zone lane closures has been a focus of the Texas Department of Transportation (TxDOT) for several years. An ongoing widening effort on Interstate 35 (I- 35) through central Texas prompted officials to examine and implement technologies to help mitigate the impacts of end-of-queue warning crashes. An end-of-queue (EOQ) warning system was established, consisting of a highly-portable work zone ITS of easily-deployable radar speed sensors linked to one or more portable changeable message signs (PCMS), and highly-portable transverse rumble strips. The EOQ system is deployed upstream of nighttime lane closures where queues are expected to develop. Although the sample sizes are relatively small, the trends do suggest that the systems are having a positive effect in reducing crashes. Overall, the EOQ warning system was estimated to have reduced crashes 44 percent from what they would have otherwise been if the system had not been used. The crashes that did occur were less severe, most likely because fewer of them were of the high-speed rear-end collision variety. Using traditional societal crash cost values updated to 2014 dollars, the use of the EOQ warning system at nighttime lane closures reduced crash costs by $1.36 million over the analysis period. This equates to $6,313 in crash cost savings per night of deployment. Compared to the approximate costs of procurement and deployment of these systems, a break-even point is achieved after 95 to 190 nights of use.