When driving in a 30 mph zone, how many car lengths should you remain behind the vehicle in front of you?

In a 30 mph zone, maintaining a safe following distance is crucial for preventing collisions, especially in case of sudden stops by the vehicle in front of you. The appropriate rule of thumb for following distance is often cited as one car length for every 10 mph of speed. Therefore, when traveling at 30 mph, it is advisable to stay three car lengths behind the vehicle in front of you.

The recommendation for six car lengths reflects the principle of allowing for increased safety, particularly under conditions where visibility may be reduced or the road conditions may be poor. This extra space helps in providing more time to react, which is critical at any speed but especially important when close to the maximum speed allowed in that zone.

In summary, the correct choice emphasizes the need for a buffer that allows for adequate reaction time while driving in a relatively lower speed zone.