Depends on the area but yeah many intersections use sensors (cameras, sometimes under the road pressure sensors, etc) to make anywhere from subtle to extreme changes based on traffic patterns. The under the road pressure sensor has been around for decades.

When I was a kid there was one light that, when you drove over the pressure sensor, it wouldn't really do much. But if you backed up and drove over it again it must have registered an additional car coming through and the light would almost immediately go through its light cycle to change. It was really interesting to see!

Nowadays I think it's mostly cameras? We have a light near my home and the left signal will literally never trigger unless someone is in one of the left lanes.