Vehicles will line up correctly at the Start/Finish line most of the time, but there are situations where one or more vehicle can get slightly ahead or behind the others. A game of Takeover that requires Supercars and Supertrucks on the track, is one of these occasions.
Having the vehicles rescan the track usually results in a correct lineup.
If you prefer, you can just move the vehicles slightly forward or backward to line them up before you begin the game. This will not alter the results or the start of the game in any way.