An alternative design for traffic intersections with work zones by using pre-signals

The lane closures caused by the work zone at the approaches create a negative impact on the operational effectiveness of the signalized intersections. This paper presents an innovative design for intersections with work zones to improve the intersection’s practical capacity. In this design, the lanes in the leg with work zone can be used dynamically as approach and exit lanes during different periods of a signal cycle by using the pre-signal. An optimization model for an optimal geometric layout and signal timing design is built to capture real-world operational constraints, including the lane assignment, the signal timing of the main signal and pre-signal, the distance of the mixed-usage area and the transition area, and the degree of saturation restriction. A case study and extensive numerical analysis demonstrate the effectiveness of the prospective design as compared with conventional designs under different geometric layout and traffic demand situations. Overall, the proposed design can lead to an increment in the practical capacity of the intersection with a work zone (by up to 30%) and reduce the average vehicular delay accordingly (by 50%) without necessitating an expansion of the intersection. The results show that the promising application of the proposed design when the length of the work zone is less than 160 m.