For which of the following reasons should speed be reduced below the posted speed limit?

Reducing speed below the posted speed limit is essential in certain conditions to ensure safety. Heavy traffic conditions can create a more complex driving environment, as vehicles may be closer together, and there’s an increased likelihood of sudden stops or starts. In such situations, driving at a speed below the limit allows for more reaction time and can help prevent accidents.

Adverse weather conditions, like rain, snow, or fog, can significantly affect visibility and road traction. Slippery surfaces necessitate slower speeds to maintain control of the vehicle. Decreasing speed in these conditions is crucial for the safety of both the driver and others on the road.

Both heavy traffic and adverse weather increase the risk of accidents, so adjusting speed in these scenarios is a proactive approach to safer driving, making this choice the most comprehensive response to the question.