I rented a car a couple of years ago that read speed signals and kept them in the dashboard for about 30 extra seconds. It was great usability. It only dealt wi

I rented a car a couple of years ago that read speed signals and kept them in the dashboard for about 30 extra seconds. It was great usability. It only dealt with speed limitations and a couple of other signals, though - if it dealt correctly with “next exit” signs I would never buy a car without that system.