Evaluate the following statement: Starting the engine or using the air conditioning in an automatic vehicle may cause the car to lunge forward.

Evaluate the following statement: Starting the engine or using the air conditioning in an automatic vehicle may cause the car to lunge forward.

• A. False
• B. True
• C. Cannot be determined
• D. Depends on circumstances

Answer: (B)

Starting the engine or turning on the air conditioning changes the load on the engine, and the engine responds with a brief change in idle behavior. That momentary change in torque can push the car forward if the brakes aren’t firmly holding it or if the transmission isn’t fully in Park. In automatic vehicles, the extra load from the A/C compressor when it starts or the throttle response during engine start can translate into a small forward jolt when the car isn’t completely restrained. Because of that possibility, it’s reasonable to say the car may lunge forward under these conditions. The safe practice is to keep your foot on the brake and ensure the car is securely in Park (or Neutral with the parking brake engaged) before starting or turning on the A/C. This is why the statement is true: there is a real, though not guaranteed, chance of a brief forward movement during those actions.

Starting the engine or turning on the air conditioning changes the load on the engine, and the engine responds with a brief change in idle behavior. That momentary change in torque can push the car forward if the brakes aren’t firmly holding it or if the transmission isn’t fully in Park. In automatic vehicles, the extra load from the A/C compressor when it starts or the throttle response during engine start can translate into a small forward jolt when the car isn’t completely restrained. Because of that possibility, it’s reasonable to say the car may lunge forward under these conditions. The safe practice is to keep your foot on the brake and ensure the car is securely in Park (or Neutral with the parking brake engaged) before starting or turning on the A/C. This is why the statement is true: there is a real, though not guaranteed, chance of a brief forward movement during those actions.