LIDAR guns determine distance by the formula t=2d/c, where d is the distance and c is the speed of light. How does the ALP do it? I was behind a truck today, and the ALP sensors started giving a parking alert. I was at least 10 FEET away from the truck's bumper.

I've noticed that shiny things (like chrome) tend to set the thing off, much farther away than they should. How exactly are the ALP sensors determining distance?