What rule should you use to judge a safe following distance in wet or frosty conditions if driving a car?

In wet or frosty conditions, the four-second rule is recommended for judging a safe following distance when driving a car. This rule provides drivers with a greater buffer between their vehicle and the one in front, accounting for the reduced traction and longer stopping distances that are typical in such conditions.

When the road is wet or icy, the stopping distance increases significantly due to the decreased friction between the tires and the road surface. By maintaining a four-second gap, drivers can better react to emergencies and avoid collisions, as this time allows for sufficient braking distance and reaction time in slippery conditions.

Using this rule is especially important in adverse weather, as a shorter following distance could easily lead to accidents if the vehicle in front suddenly brakes or stops. In contrast, shorter rules like the two-second or one-second rules may not provide adequate space for safe stopping in these challenging driving conditions.