Final answer:
The best braking technique to maintain a safe speed when driving downhill is engine braking. This technique involves using the engine's compression to slow down the vehicle. Hybrid and electric cars also utilize regenerative braking to slow down the vehicle and recharge the battery.
Step-by-step explanation:
The best braking technique to use in maintaining a safe speed when driving on a downhill descent is engine braking. Engine braking involves shifting into a lower gear and using the engine's compression to slow down the vehicle. This technique is preferred because it puts less strain on the brakes and helps prevent them from overheating.
In addition to engine braking, modern hybrid and electric cars also utilize regenerative braking. This technology converts mechanical energy into electrical energy, which is then stored in the battery. Regenerative braking helps to slow down the vehicle and recharge the battery at the same time.
Overall, engine braking and regenerative braking are effective techniques for maintaining a safe speed when driving downhill.