Impact of Shoulder Use and Capacity Reduction Factors on Highway Work Zone Optimization

Highway maintenance, often requiring lane closure, is very expensive in terms of the costs associated with transportation agencies (i.e., work zone setups) and road users (i.e., delay). Longer work zones tend to increase the user delay but will be efficient because of fewer repeated setups. To increase road capacity and mitigate congestion impact for a short-term work zone, temporary shoulder use may be applied. This study develops an analytical model to optimize work zone length on a multi-lane highway considering time-varying traffic volume and road capacity affected by light condition, heavy vehicle percentage, and lane width. The results can be used to evaluate the work zone impact (i.e., delay and cost) and assisting engineers/planners to prepare and develop a cost-effective highway maintenance plan. A case study for a highway work zone in New Jersey is conducted, in which the optimized solution was found. A guideline of using road shoulder under various circumstances is developed.