I would willingly pay good money for the following OBD-2-related device (could be implemented completely in hardware, no empeg connection necessary):

- Monitor the vehicle speed continuously.
- If the vehicle is traveling over 30 miles per hour,
- Then close a relay and keep it closed as long as the vehicle is traveling over that speed.
- When the vehicle drops below 30 miles per hour, open the relay again.

This relay would be connected to the speaker wire on my radar detector. This would stop the radar detector from making noise when I am navigating a grocery store parking lot. I'm surprised there aren't any radar detectors which do this already.