Well, Navtech covers the north america, western europe and a few asian countries at the moment. They have well over a thousand employees. They started out with the TIGER data, and they have dedicated drivers go out in pairs taking turns navigating and recording details of the road -- one way streets, intersections, etc. Every quarter, they manage to hit most of the roads to issue updates and changes to the road topology and are considered very accurate.

Garmin, Alpine, Kenwood, Rand McNally are all customers of their data.

Calvin