You know how this scene goes. You’re out driving. It is late in the evening, so traffic is down to a minimum. You’re cruising down the street, and suddenly, just as you approach, the light in front of you goes red. It has been green, green, green throughout your approach, but then, as if perfectly timed to confound you, it turns red just BEFORE you are close enough to coast through on the yellow. So you stop.
Then, you proceed to get irritated by the fact that there is not a single vehicle at, near, or even in sight of the intersection on the other road. For the entire duration of the green light, NOT ONE car passes through along the other road.
And yes, eventually the light changes again and you can proceed.
You know all these lights have weight sensors to control the lights, so you’re not sure why the timer is running at this time of day. Still, you get the feeling that somehow, someone over at the traffic control department is having a laugh at your expense.
Been there?
Those sensers are not in every light, and are used primarily in turning lanes to show protected turn lights only when they are needed. The lights must cycle normally in low traffic conditions by law, I think.