Final answer:
To maintain a safe distance, consider stopping distance, braking distance, and the length of the average car.
Step-by-step explanation:
To maintain a safe distance from the vehicle ahead of you in ideal conditions, you must follow the concept of stopping distance in physics. Stopping distance is the total distance traveled by the car from the point where the driver first sees a light turn red until it comes to a stop. It depends on factors like the initial speed of the car, driver reaction time, and road conditions.
One way to estimate a safe distance is to consider the braking distance, which is the distance covered by the car while braking to a stop. This distance varies depending on the initial speed. For example, for a car initially traveling at 30.0 m/s on dry pavement, the braking distance might be around 45 meters.
Considering the length of an average car (e.g., 3.5 meters) and adding a safety margin, it is recommended to maintain at least a distance equal to the length of multiple cars (like 2 or 3) to cross a road safely, especially in towns and cities with a speed limit of 60 km/hr.