Assessing the Benefits of Smart Work Zone Systems

Smart work zones (SWZs) are being deployed around the United States as a way to inform drivers dynamically about traffic conditions within a work zone. SWZs use sensors to detect traffic flow conditions on the work zone approaches. These data are then used to alert drivers of congestion or speed differentials in an effort to improve operations or safety. Agencies that are considering deploying SWZs are often faced with the challenge of trying to justify the cost of an SWZ system to decision makers who may be more inclined to use the funds for more traditional maintenance purposes. Although a number of states have evaluated SWZ systems, there has not been much effort to identify trends across multiple tests or extend those findings to predict likely impacts of proposed deployments. This paper synthesizes the results of a number of deployments of SWZ technology and identifies some common trends in performance. The data are then used to develop benefit-to-cost (B/C) ratios for a variety of traffic and diversion alternatives. The B/C ratios are then used to identify some project duration thresholds at which an SWZ would be beneficial based on user delay savings for a two-lane directional segment. TRB 2007 Annual Meeting CD-ROM Paper revised from original submittal.