I live in NH, where they have been in the process of upgrading the toll booths to handle EZPass over the past year or so.
Over the past few months, when I go through the toll booths, 4 out of 5 times my V1 will sound a Laser alert just as I'm starting to pull out of the booth after paying the toll. There must be some piece of equipment that was recently installed in the booths that is causing this. I've had the alerts in both manned and automatic (exact-change) lanes.
I've googled but haven't found anything definitive (actually, that's how I discovered this site). I've heard the possibility of lidar being used to measure the speed of cars going through the booth, or of the video cameras using IR emitters that cause laser falses (unlikely as I've gotten the alert even in booths that had no cameras). I also read of a lidar system that determines the size of the vehicle going through the booth, perhaps to charge large trucks more. But I haven't found any definitive cause or reason for the laser alerts.
Any ideas? Just curious.