Final answer:
The recommended following distance on interstates is at least 3 seconds to ensure safety, which is demonstrated through Bridget's observations and calculations pertaining to vehicle speeds and stopping distances.
Step-by-step explanation:
The question 'On interstates, your following distance should be at least' refers to the safe following distance a driver should maintain when driving on an interstate. The generally recommended following distance on highways is at least 3 seconds, which allows for adequate space between vehicles to safely react and stop to avoid potential collisions.
Bridget's observation from her classroom window of cars taking 3 seconds to travel 50 meters offers a real-world example of this principle.
Considering that the average speed in towns and cities is 60 km/hr, and the average car length is 3.5 meters, it's important for pedestrians to wait until a car is far enough away before crossing, typically more than the length of 8 cars (28 meters), to account for the car's stopping distance and the pedestrian's walking speed. Moreover, the stopping distance for a car varies depending on road conditions and driver reaction time, so pedestrians should always err on the side of caution.