To mitigate the work zone impacts on freeways, an advanced traveler information system (ATIS) was designed to promote the utilization of alternative routes and improve local road network performance. The system evaluation was performed during a bridge reconstruction project on the four-lane divided I-39/90 near the interchange with WIS59 at Edgerton, Wisconsin. Field comparisons between ATIS presence and absence discovered different diversion patterns in northbound and southbound directions associated with traffic delay. Drivers remained on the freeway when the displayed delay was less than 15 minutes while more drivers chose to leave the freeway with displayed delay greater than or equal to 15 minutes. A linear regression analysis was further conducted to investigate the impact of several factors, such as displayed delay time, freeway volume, exiting volume during the normal days (without a work zone), and the number of days after system implementation, on driver’s diversion behavior. The results showed that freeway volume, ramp exiting volume during normal days, and delay time were significant variables in causing a high diversion rate.In addition, it was demonstrated that ATIS performed effectively in increasing the work zone operational capacity. Furthermore, the reduced operating speed associated with the advance speed warning (part of the system) suggested that drivers reacted to the warning messages responding to the real-time speed collected through detectors. This comprehensive evaluation enriched the knowledge of driver behavior and reaffirmed the effectiveness of ITS applications in congestion mitigation.
