Those are sometimes called " bread crumbs". There has to be mention of this inside the manual. There is an option in menu to turn trip recording on or off. You can record up to 150 miles of track you covered, the red spots are points showing you that recorded track you previously drove. This could be helpful to back track your way in some unfamiliar area, or see where you or somebody else drove. It could be very useful at times and if you only drive locally will multiple tracks driving you crazy, turn it off.