Evaluation of Construction Work Zone Operational Issues: Capacity, Queue, and DelayAuthor/Presenter: Benekohal, Rahim F.; Kaja-Mohideen, Ahmed-Zameem; Chitturi, Madhav V.
The Illinois Department of Transportation (IDOT) requires queuing analysis to determine traffic backups on interstate work zones. The monetary gains/losses in contractual procedures such as lane rental and incentive/disincentive depend on the queuing analysis. The statewide survey indicated that incentive/disincentive and lane rental procedures were more effective in reducing duration of work zones and delay. The survey of state DOTs indicated that for estimating capacity the Highway Capacity Manual (HCM) technique was used; for estimating queue length and delay, QUEWZ, QuickZone, and HCM technique were used; and for estimating road user costs, QUEWZ and spreadsheets were used more often than other techniques. About 57% of the DOTs said they use Intelligent Transportation Systems (ITS) technologies in work zones. Headway and traffic flow data were collected and analyzed for 14 work zones in Illinois. Field data were compared to the results from FRESIM, QUEWZ, and QuickZone software. QUEWZ overestimated the capacity and average speed, but underestimated the average queue length. Speeds computed in FRESIM were comparable to the average speeds from the field data when there was no queuing at the work zones. However, when there was queuing, FRESIM overestimated the speed. The queue lengths obtained from FRESIM were shorter than the field values in half of the cases and longer in the other half of the cases. The queue lengths from QuickZone did not match the field data and generally QuickZone underestimated the queue lengths. QuickZone consistently underestimated the total delay observed in the field. When demand is less than capacity QuickZone does not return any user delay because it does not consider the delay due to slower speeds in the work zones. A new methodology was developed to determine capacity, speed reduction, delay, queue length, and user costs. Speed reductions due to the work zone factors are used to compute operating speed. Then, capacity is determined using speed flow curves developed in this study. Finally, queue, delay and user costs are computed.
Publication Date: December 2003
Full Text URL: Link to URL
Publication Types: Books, Reports, Papers, and Research Articles
Topics: Costs; Disincentives; Incentives; Intelligent Transportation Systems; Lane Closure; Software; Temporary Traffic Control; Traffic Delays; Traffic Queuing; Work Zone Capacity; Work Zones