Yes. I can't speak to the USA, as I'm from Canada, but I've had conversations with traffic engineers from another city about it and increasingly seen them in my own city. Here's an example of one of the systems: https://www.iteris.com/oursolutions/pedestrian-cyclist-safet...
They're obviously more common in higher density areas with better cycling infrastructure. The inductive loops are effectively useless with carbon fibre bicycles especially, so these have been a welcome change. But from what I was told these also are more effective for vehicle traffic than the induction loops as drivers often come to a stop too far back to be detected, plus these also allow conditional behaviour based on the number of vehicles waiting and their lanes (which can all be changed without ripping up the road).
Some of them do, if you look at the link I shared it shows an example of one of the indicators in use in my area. But you can usually tell anyway. You don't think about it as much in a vehicle but on my bike you get used to how each intersection triggers. Sometimes I have to edge forward into the intersection to let a car come up behind me and cover the loop, sometimes I have to come out of the bike lane into the vehicle lane, some intersections have ones that are set sensitive enough to pick up a bike with alloy wheels but not carbon wheels, some of them require cyclists to press a button, some have cameras, etc.
For e.g. there was one intersection way out of town that would always have a decent amount of main-way traffic but barely any cross traffic and had no pedestrian crossing. I would always get stuck there hoping a car comes up behind me, or trying to play chicken across the main-way moving at highway speeds. I assume someone complained as it's a popular cyclist route, because they put in a camera and now that intersection detects me reliably, no issues there since then.
They're obviously more common in higher density areas with better cycling infrastructure. The inductive loops are effectively useless with carbon fibre bicycles especially, so these have been a welcome change. But from what I was told these also are more effective for vehicle traffic than the induction loops as drivers often come to a stop too far back to be detected, plus these also allow conditional behaviour based on the number of vehicles waiting and their lanes (which can all be changed without ripping up the road).