Some of them do, but that should be extended. One of the roads I travel has a lot of truck traffic in one direction and mostly cars in the other, and I would think it would be advantageous for the sensors to detect half a mile away if a truck is coming and give him a green light so he doesn't have to stop.
Evidence of meeting #44 for Natural Resources in the 39th Parliament, 1st session. (The original version is on Parliament’s site, as are the minutes.) The winning word was work.
A recording is available from Parliament.