Alternative Driver Information to Alleviate Work-Zone-Related Delays
McCoy, Patrick T.; Pesti, Geza; Byrd, Patrick S.
The overall objective of the research documented in this report was to find better ways to control traffic at work zones on rural interstate highways. The primary focus was on improving the safety and efficiency of the merging operations in advance of lane closures. The research involved the identification and evaluation of alternative strategies designed to control traffic speeds and merging operations in advance of lane closures. Twelve alternatives were identified as a result of a literature review, brainstorming session, and survey of states. The alternatives and the existing merge control strategy used by the Nebraska Department of Roads, NDOR Merge, were evaluated using computer simulation. In addition, field evaluations of the NDOR Merge and two alternatives, the Indiana Lane Merge and Late Merge, were also conducted. Field studies of the Indiana Lane Merge and the Late Merge were conducted at work zones in Indiana and Pennsylvania, respectively. Field studies of the NDOR Merge were conducted at work zones on I-80 in Nebraska. The field data were used to determine the safety and perational effects of these merge control strategies. A benefit-cost analysis was performed to evaluate the cost-effectiveness of four alternative traffic control strategies relative to the NDOR Merge. The four alternatives evaluated were: (1) the Indiana Lane Merge, (2) Late Merge, (3) Enhanced Late Merge, and (4) "Smart" Work Zone. The Enhanced Late Merge is a traffic-responsive Late Merge. During low to moderate traffic volumes, early merging operations like the NDOR Merge are in effect. When traffic volumes are above a predetermined threshold, the Late Merge is in effect. The "Smart" Work Zone is capable of detecting congestion and providing real-time advisory information to travelers encouraging them to divert to an alternate route. The net benefits of the alternatives were calculated, and a breakeven analysis was performed to identify the most cost-effective alternatives over the range of traffic volumes and truck percentages expected on rural interstate highways in Nebraska over the next 20 years. The NDOR Merge was found to be the most cost-effective merge control strategy for directional ADTs below 16,000 to 20,500 vpd depending on the percentage of trucks. The Late Merge, Enhanced Late Merge, and "Smart" Work Zone were the most cost-effective alternative at higher traffic volumes. The Indiana Lane Merge was not found to be the most cost-effective alternative under any of the traffic conditions investigated.
University of Nebraska-Lincoln, Mid-America Transportation Research Center