There is an almost endless number of stories about people who were led astray by the GPS devices in their cars. Right now, are 49 million users in the United States, including in-car systems, portable units and smart phones, according to Telematics Research in Minnetonka, Minn. It’s not surprising that outdated routes, closed roads, and bad directions are found.

Problems arise with information put into the devices in order to provide directions. Map data companies like Tele Atlas and Navteq have employees in the field checking everything they can, but GPS makers also rely on other sources including transportation departments, building associations and public records. Keeping information current is a battle.

When your GPS directs you off the main road or in the wrong direction, think twice before taking that route.