2, the roadway, and your vehicle are all categories associated with risk that you should assess before you get behind the wheel.

The missing answer is "The driver".

Before getting behind the wheel or driving, one must assess the roadway, the driver and the vehicle itself to check and manage potential risks that may affect the lives of the driver and the passengers as well. One must check the roadway if the road has any abnormalities or constructions ongoing, such as road fixings or weather related causes. One must also assess the driver if he or she is still worthy of driving, or if he or she is fit for driving for the day, and lastly, one must consider checking the car to fix any potential risks that may harm the lives of the people in the vehicle.

3. i would say one, but one is not prime nor composite.