Even in normal, non-freezing conditions, why is it good practice to use wheel chocks when the parking brake is set on a grade?

Pick an answer

1. Chocks replace the need for the parking brake entirely, since a properly placed chock alone can hold a fully loaded vehicle on any grade
2. Chocks are required only by company policy, never for safety
3. Chocks are only used during loading, never for parking
4. Chocks provide a backup if the parking brake were to fail or slip, since a vehicle on a grade will roll if nothing else holds it

Correct!

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