My contact at NavTech tells me that the TIGER data is notoriously inaccurate. That is why they have an army of drivers that drive the roads and streets of the entire country verifying the accuracy of the data. They go in teams of two, with a driver and a mapper. They ensure that one way streets are real, that changes in the road system is reflected. The updated data is proprietary. In addition, they use satellite maps and other data to make sure everything is right. Because of this army of people, the NavTech data is the most accurate but also the most costly as you can imagine. They cover north america from canada all the way down to latin america and western europe.

Calvin