What do you need in addition to seeing a hazard to stop a vehicle effectively?

To stop a vehicle effectively upon seeing a hazard, time to think about the situation is crucial. This allows the driver to assess the hazard, determine the appropriate response, and execute the necessary actions. Quick decision-making is essential for safety, particularly in emergencies, where a lack of time could lead to panicked or ineffective responses.

The other choices may have their relevance in specific contexts, such as needing a clear road to safely come to a stop, but they do not directly relate to the immediate necessity of processing what has been observed. Similarly, while permissions and additional braking systems can be beneficial, they are not fundamental to the quick reaction required to avoid the hazard once it has been identified. Hence, having the time to think through the situation stands out as the most critical factor for effective stopping.