Final answer:
Maintain a significantly increased following distance when driving at 30 mph on icy roads, potentially 8 to 10 car lengths, to ensure enough time for hazard perception, reaction, and stopping.
Step-by-step explanation:
When driving on icy roads, it is crucial to maintain a safe following distance from the vehicle in front of you. While the standard safe following distance is often cited as the 3-second rule in good road conditions, icy roads demand a significantly increased margin for safety. If you are traveling at 30 mph on icy roads, it is recommended to leave much more space than you would under normal conditions, due to the reduced traction and longer stopping distance required.
Although there isn't a universally agreed upon number of car lengths, considering that an average car length is approximately 15 feet, a safe rule could be to stay at least 8 to 10 car lengths behind the vehicle you are following on icy roads. This increased distance accounts for the extra time it takes to perceive a hazard, react, and bring the vehicle to a stop on slippery surfaces.