Highway repair and maintenance projects (e.g. deck replacement, resurfacing, joint repairs, utility works, etc.) occupy the road and disrupt traffic operations, which increase delays because of reduced capacity. According to an urban mobility report conducted by Schrank et al (2010), it was indicated that traffic congestion in 2009 caused urban Americans to travel an additional 4.8 billion hours and to purchase an extra 3.9 billion gallons of fuel, which is equivalent to a congestion cost of US$115 billion. The growth in the vehicle-miles travel has far exceeded the lane-miles increased to the highways. Extending the life of existing roads and efficiently utilizing the available capacity to meet the mobility needs is highly desirable. Temporary work zones (TWZs) have become a necessary feature of U.S. highways, which have been the second largest contributor to the non-recurring delay. The delays caused by TWZs are nearly 24 % of all non-recurring delay and 10% of overall delay in the United States.

In addition to congestion impact, construction and maintenance operations on highways also increase safety concerns to motorists, pedestrians, and workers. The delay costs to users caused by TWZ may far exceed the maintenance and traffic control device setup costs. Efficient traffic management through a TWZ may greatly reduce the total cost, including user and agency costs. It is desirable to develop a model which can be applied to evaluate the impact of traffic diversion and managed lanes (i.e. the use of road shoulders) on highway work zones. The costs and benefits can be measured in terms of changes in vehicle delays and velocity, number of accidents, GHG emissions, as well as addition cost for increasing road capacity.