I've always wanted a feature like this on my car. A GPS geocache or RFID based system to let me know about current speed limits and speed limits ahead of me. Often the signs are so far apart on some roads I don't know the speed limit of the road I turned onto until miles have passed. In addition it would be cool if my cruise control could adjust for slow downs and my gas pedal could have a sticky location for the speed limit. Something to make breaking the speed limit more intentional.<p>Virtual road signs that my car could read and alert me about would be a great addition to the ones on the side of the road too. Stuff like upcoming crosswalks and deer crossings.