Driver behaviour at signalized intersections in relation to yellow intervals.

The stopping behaviour of 1.762 drivers was observed at two signalized intersections by using time lapse photography. Only about 10% of the drivers chose to stop upon yellow onset when to do so required a deceleration rate of 15 ft/sec. The results show that reducing the limiting deceleration rate from 15 ft/sec2 to 10 ft/sec2 in the formula for setting yellow clearance intervals would substantially reduce the numbers of vehicles still in the intersection when the cross traffic signal turns green.