Two-second rule two seconds as inadequate, and recommend a three-second rule. German law requires a minimum 0.9 second distance but when tested under relaxed conditions researchers found that their test subjects spent 41% of the test time at following distances under 0.9 second. The United States National Safety Council suggests that a three-second rule—with increases of one second per factor of driving difficulty—is more appropriate. Factors that make driving more difficult include poor lighting conditions (dawn and dusk are the most common); inclement weather (ice, rain, snow, fog, etc.), adverse traffic mix (heavy vehicles, slow vehicles, impaired drivers, pedestrians, bicyclists, etc.), and
Five-second rule Five-second rule The five-second rule, sometimes also the three-second rule, is a western cultural food hygiene concept, that states that there is a defined window where it is permissible to pick up food (or sometimes cutlery) after it has been dropped and thus exposed to contamination. Some may believe this assertion, whereas most people employ the rule as an amusing social fiction that allows them to eat a dropped piece of food, despite the potential reservations of their peers. How many and what type of bacteria would stick to a piece of dropped food depends on many factors, the food