Dynamic No-Passing Zone for Construction Safety

This paper presents information on the Indiana Department of Transportation’s dynamic no-passing zone system which was developed with the assistance of International Road Dynamics. The system uses a series of signs that display the message “Do Not Pass When Flashing.” These signs are placed upstream of a construction zone and each has a set of flashing amber beacons which can be activated automatically. When the congestion at a construction site begins to increase, the signs further upstream are activated, which expands the length of the no passing zone and directs vehicles to change lanes before the point of congestion. The system was developed in order to address the problem of drivers staying in closed lanes until the last moment and then making abrupt lane changes.