A new approach of work zone delay cost analysis is developed to understand the implications of detours. This method, unlike any of the previous methods, is based on the impacts within the transportation network and let users find the shortest paths which will eventually come to equilibrium. The total work zone cost consists of total delay cost, work zone set-up cost and accident cost. The analysis is based on an illustrative transportation network, the Sioux-Falls network. The total delay cost is calculated using User Equilibrium assignment to distribute all the traffic. To solve for User Equilibrium, the Frank-Wolfe algorithm is implemented via Matlab. The total delay cost is then converted to a monetary value using value of time (VOT). The work zone set-up cost and accident cost relate to number of work zone segments and total length of work zone. This thesis illustrates the importance of considering the opportunity for detours when considering the design of work zones for road construction.