When should a professional driver calculate their turning radius distance?

Calculating the turning radius distance before beginning the turning maneuver is crucial for a professional driver to ensure safety and proper navigation. This assessment helps the driver to identify whether the vehicle can successfully make the turn without encroaching on adjacent lanes, hitting obstacles, or colliding with other vehicles or pedestrians. By understanding the turning radius in advance, the driver can adjust their approach to minimize risks and ensure a smooth, controlled turn.

In contrast, conducting this calculation after completing the turn does not provide any benefit for the current maneuver and could lead to unsafe situations if a reminder is needed for future reference. Evaluating the turning radius while approaching an intersection may not provide enough time to react or adjust the path effectively if sudden obstacles arise. Calculating during the turn itself can be risky, as it diverts attention away from controlling the vehicle, which is critical for safe execution of the turn. Therefore, the optimal time for this calculation is prior to initiating the turn, allowing for proactive decision-making.