Why do some Ministry traffic signals have yellow “PREPARE TO STOP” signs with yellow flashers on them in advance of intersections? How do they work?
The Ministry installs “Prepare to Stop” warning signs at traffic signals when: • the road has a posted speed of 70 km/h or higher; • there is restricted vertical or horizontal sight distance; • the traffic signal is the first one after a long stretch of driving without encountering another traffic signal; • on steep downhill grades. These signs are used to provide additional guidance to motorists and allow a gradual deceleration before the signal changes to a yellow light. The flashers are programmed to come on at a given interval before the yellow signal comes on. This interval time will vary depending on the speed limit and grade at the site.
