In traffic signal timing, this is the specific interval, usually a yellow light followed by an all-red phase, that allows vehicles already in the intersection to exit safely. Traffic engineers calculate this based on intersection width and average vehicle approach speed. Insufficient clearance time leads to right-angle collisions, especially involving long commercial vehicles that take longer to clear the box.
Heard on the job
We need to increase the clearance time at the main junction because the tandem trailers are still in the intersection when the cross traffic gets a green light.
Also heard as
- all-red interval
- clearance interval