Final answer:
You should park at least 500 feet away from a fire truck answering a call, which is approximately 12.5 car-lengths.
Step-by-step explanation:
The distance from a fire truck that is answering a call may vary depending on the specific regulations and circumstances. However, in general, it is recommended to park at least 500 feet away from the fire truck to ensure a safe distance and allow emergency responders to carry out their duties without obstruction. As an example, if we assume the length of a fire truck to be 40 feet, you would need to park at least 12.5 car-lengths away from the fire truck, considering the average length of a car to be around 16 feet.
It is important to keep in mind that these values may vary based on local traffic laws and emergency response protocols, so it is always best to follow the instructions and guidelines provided by the emergency personnel at the scene.