I was using autopilot on a road I travel daily, in the right hand lane on a three lane (each side 3 lanes 6 total) highway. I was very confused as to why my car was slowing down with no cars in front of me, that's when I noticed the dash said 5mph speed limit and auto steer was limited to 10mph. What does AP use to determine speed limit? GPS or the camera? Like I said I travel this road daily and never had a problem before. Posted speed limit is 45mph.