Take the first right turn and follow it down. Turn left to go to the Tropicana area. Turn right at the second street, then take the first left turn. Follow the "S" curve and stop at the crosswalk. Look left to see a gate and a building. Follow that building with the four cones in front of it. At the end of the building is an opened gate. Turn in there and you will see the switch next to the fence at the end of the building. Get out of your car and walk over to the switch. Press Triangle to open the gate you first saw. Get back in your car and drive around into the now open area. The secret car will be behind the building in front of you.