Work Zone Lengths for a Four-Lane Road with an Alternate Route

Abstract

Highway maintenance, like rehabilitation or resurfacing, on four-lane, two-way highways usually requires closing one or two lanes to set up a work zone. In this paper we evaluate several alternatives defined by the number of closed lanes, fractions of traffic diverted to alternate routes, and crossover of diverted traffic to opposite lanes. A methodology is developed to minimize the total cost, including agency cost, user cost, and accident cost, by optimizing work zone length for each alternative and finding optimal diversion fraction, while considering the characteristics of the detour route bypassing the work zone. Finally, guidelines for selecting the best alternative for different characteristics of traffic flows, roads, and maintenance processes are developed by deriving thresholds among alternatives.