WOW! Did that ever work. There's a trail close to me that has a one mile stretch marked off. I set the trip feature at the first post and it turned over to one mile within inches of the one mile post. I did about a dozen miles and then did it again on the way back. This time it was within about three or four feet. I'm in the National Bike Challenge this year and so I wanted it to be as accurate as possible, but I never dreamed it would be this close.