Keep in mind that a GPS works by using satellites. I love mine, but every once in a while, it'll blip and say my max speed was 400 MPH or something like that. In general though, it works well. It doesn't work as well if you use it amongst tall buildings and it doesn't work at all if you can't see the sky. I've found that I use it when I drive now too. I'm chronically lost. It's a cool toy.