Drive below the posted speed limit when:
- Anything makes conditions less than perfect. ✓
- You see a police car.
- Entering a highway where there are other cars.
- You are on a four-lane road.
Answer: A. Anything makes conditions less than perfect.
Drive below the posted speed limit whenever anything makes conditions less than perfect, such as bad weather, the roadway itself, or traffic.
Why this is the answer
The handbook explains that posted speed limits show the fastest you may drive under favorable conditions. It says you are responsible for adjusting your speed to the weather, roadway, and traffic conditions, and gives a storm as an example of when to drive slower than the limit. It also says the safest speed is the one that lets you keep complete control of your vehicle and avoid collisions, so anything that makes conditions less than perfect calls for a lower speed.
Why the other answers are wrong
- B. You see a police car. — Seeing a police car is not what the handbook gives as a reason to drop below the limit; the rule is about adjusting to the weather, roadway, and traffic conditions.
- C. Entering a highway where there are other cars. — Entering a highway with other cars is not stated as a general reason to drive under the posted limit; the handbook ties speed to how favorable the conditions are, not to a specific road situation like merging.
- D. You are on a four-lane road. — Nothing in the handbook says a four-lane road by itself means you should drive below the posted speed limit; the limit still applies when conditions are favorable.
Remember it
Think of the posted number as the best-case speed, not the everyday speed: worse conditions, lower speed.