Go to Take A Ride mode and choose the 18 Wheeler. Start driving fast and head onto the wrong side of the road. When you see a car coming towards you, ram it head-on. Then, get out of the vehicle and you can see that the driver of the car you rammed died on impact. Note: Try to back your truck back onto the correct side of the road because the cops will arrive to investigate the accident. If you keep driving on the wrong road they will come after you.