It is not possible to play as the Police in Need for Speed: Most Wanted. It is how ever, highly possible to be chased by the police in many parts of the game. However the Police cars can be driven in the Challenge series and through hacked game save files. The marked units and the Rhino Heavy are the only ones that can be played as while the Undercover, Rhino Light and Cross' Corvette and the helicopter can cause the game to crash since they were meant to be AI cars now the helicopter can be flown with a special program called copter mover.or you can play through the challenge series.