I have tried this with Rand McNally and Garmin now. I need to have my GPS unit follow me as I drive and collect data along the route. I then need it to save that route and then use turn by turn navigation to repeat it. The Rand McNally would allow you to follow a route but no audio navigation; the Garmin will create a track of your route but not allow you to repeat it. Anyone know what device can do this? I have 200+ turns to perform each night in a garbage truck. I need to be able to put a driver in the truck and send them on the exact route I just ran.