Chase the black Brevis car and stop it. Then take Tyler into the police station. Leave your car outside the station and go the rest of the way on foot. Go throught the entrance to the police station until your car is out of sight. You will then notice that your car has disappeared and so has all the traffic around the city, apart from the cops on motorcycles. You can ride on a bike and have Tyler sit on the back and go on a sightseeing tour with the bike.