Final answer:
It is important to consider the fastest speed, the slowest reaction time, and the longest stopping distance in calculations to ensure safety and account for adverse conditions on the road.
Step-by-step explanation:
It is important to use the fastest speed, the slowest reaction time, and the longest stopping distance in calculations because these values represent extreme scenarios that ensure safety and account for unexpected situations on the road. By considering the fastest speed, we can calculate the maximum stopping distance required to bring the vehicle to a halt, which is crucial in preventing accidents. The slowest reaction time is used to account for delayed response from the driver, ensuring that enough distance is allowed for the vehicle to stop. Lastly, the longest stopping distance takes into account unfavorable conditions such as wet pavement, which requires a greater distance to stop.