Chapter 4 of 516% of exam
Speed & Conditions
Legal speed depends on posted limits and on the conditions you face.
Reasonable speed
Always drive at a speed that is reasonable and prudent for conditions, never faster than is safe even when it is below the posted limit. Both driving too fast and too slow can be dangerous.
Common posted limits
Unless otherwise posted, the limit is 30 mph in business and residential districts, with lower limits, commonly 20 mph, in active school zones. Interstate and rural limits are higher and clearly posted.
Adjusting for conditions
Slow down and add following distance in rain, fog, or on wet roads to avoid hydroplaning. Reducing speed shortens stopping distance and gives you more time to react.