Can vary. May be a single car with radar in the median clocking traffic in either direction. Most commonly it is an officer standing in the door of an SUV with a laser and at least two cars waiting for the go ahead from the officer clocking traffic. The latter scenario is generally during evening rush hour clocking northbound traffic. They sit in a location that is very open, but it sits in a low spot so that you cannot see them as you come over a rise from either direction until it is too late.