I saw a TV special once about how they hire people who drive around cities with a bunch of high tech cameras mounted on their cars and record the road details. When you think about it, the process is massive. Someone told me NavTeq updates maps on their own but they do it geographically, so they may drive thru the Northeast this year and the West next year. It speeds up the process if someone actually reports an error/correction to Navteq. Map corrections can sometimes take YEARS to make it onto the new maps. NavTeq also supplies the Maps for Garmin. it's NavTeq who supplies the Maps for The Honda GPS Units (which are made by Alpine).
