Rules and conditions
Drive at a speed safe for current conditions even when it is below the posted maximum. A posted maximum does not establish a safe speed for every weather, visibility, or traffic condition. At a blind intersection without corner stop signs, the California handbook gives a 15 mph limit. A restricted view requires time to discover crossing traffic before entering the conflict. California's handbook sets the speed limit in an alley at 15 mph. An alley combines limited sight lines and close access points, so a normal street speed is inappropriate. Within 100 feet of a railroad crossing with an obstructed 400-foot view in either direction, the handbook's limit is 15 mph unless specified control conditions apply. The restricted-view rule concerns discovering a train early enough; it is not a universal speed for every crossing.
Worked comparison
For example, heavy rain reduces visibility on a road posted at its normal maximum. The defensible response is: Reduce speed to account for the current visibility and road conditions. Compare this with the mistaken proposal: Maintain the posted maximum because it is always safe. A posted maximum does not establish a safe speed for every weather, visibility, or traffic condition. For example, no STOP signs control a blind intersection and the driver cannot see crossing traffic clearly. The defensible response is: Approach at no more than 15 mph. Compare this with the mistaken proposal: Use 25 mph because every city intersection has that limit. A restricted view requires time to discover crossing traffic before entering the conflict.
Transfer and self-check
Explain why driving at a posted maximum can still be unsafe in rain or congestion. For a numerical rule, state the location and exceptions in words before recalling the number. Check that the described crossing is uncontrolled and has the restricted view relevant to the question.
Heavy rain reduces visibility on a road posted at its normal maximum. Which response follows the applicable California handbook rule?
- Identify the relevant condition: Heavy rain reduces visibility on a road posted at its normal maximum.
- Drive at a speed safe for current conditions even when it is below the posted maximum.
- A posted maximum does not establish a safe speed for every weather, visibility, or traffic condition.
Compare the other answer choices
The proposal "Maintain the posted maximum because it is always safe." conflicts with this applicable condition: Drive at a speed safe for current conditions even when it is below the posted maximum. It does not resolve the stated risk: A posted maximum does not establish a safe speed for every weather, visibility, or traffic condition.
The proposal "Match the fastest nearby driver regardless of visibility." conflicts with this applicable condition: Drive at a speed safe for current conditions even when it is below the posted maximum. It does not resolve the stated risk: A posted maximum does not establish a safe speed for every weather, visibility, or traffic condition.
The proposal "Treat a posted maximum as a required minimum." conflicts with this applicable condition: Drive at a speed safe for current conditions even when it is below the posted maximum. It does not resolve the stated risk: A posted maximum does not establish a safe speed for every weather, visibility, or traffic condition.
Try it, then explain it.
Complete a short set without looking at the example. After each answer, explain which evidence or rule supports your decision and why the alternatives do not fit.
Sources & authorship
Original Slope explanations and examples. References support the concepts; they are not the source of copied questions. Independent educator review is pending.
California DMV laws and rules of the road cont1California DMV safe driving cont2