Driving at night, in rain and in fog
Every number in a handbook assumes ideal conditions. When the conditions change, the numbers change with them, and this is the part of the exam where people most often answer with the dry, daylight version of a rule that no longer applies.
Night: you can only stop within what you can see
The governing idea is overdriving your headlights: travelling so fast that your stopping distance is longer than the distance your lights illuminate. If something appears at the edge of your beam, you have already used all your time.
- Use high beams on unlit roads when there is no oncoming traffic and no one close ahead.
- Dim them for oncoming traffic and when following another vehicle, usually at a set distance that your handbook states, commonly around 500 feet for oncoming and a shorter figure when following.
- At night, speed and distance both shrink. Reduce speed, and increase following distance beyond the daytime figure.
- Glare: do not stare at oncoming headlights. Look toward the right edge of your lane and use the edge line as your guide until the vehicle has passed.
- Fatigue counts as a condition. Most people are worse at night than they think, and the honest fix is to stop rather than to open a window.
Rain: two dangers, not one
The first is grip. The second is visibility, and on a road where everyone can see less, everyone should be slower.
- Turn on your headlights. In many states, wipers on means lights on, and the reason is being seen rather than seeing.
- Hydroplaning happens when water lifts your tyres off the road: the steering goes light and the car stops responding. If it happens, ease off the accelerator, do not brake hard, and hold the wheel straight until grip returns. It is more likely at speed, with worn tyres or in standing water.
- The first minutes of rain are the worst. Oil and dust that have collected on dry pavement turn slick when they first get wet.
- Increase following distance well beyond the two-second rule, because the car ahead may brake harder than you expect and your own braking takes longer.
- Avoid cruise control in wet conditions; you want your foot in contact with the decision.
- Do not drive into moving water across a road. It is deeper than it looks, and it takes very little depth to move a car.
Fog: the one condition where high beams make things worse
Fog scatters light. High beams throw more light into the droplets and reflect it back at you, so you see less, not more. The correct settings are low beams, and fog lamps if you have them, aimed low and wide.
- Slow down and increase distance far beyond the dry figure.
- Do not stop on the roadway. If you must stop, get completely off the road, well away from the travel lanes, turn on hazard lights, and stay in the vehicle with your seatbelt fastened. Standing outside a car in fog is where pedestrians get hit.
- Use the right edge line as your guide rather than the centre line, so a drifting oncoming car does not take you with it.
- Look for the pavement itself when the lane markings disappear; fresh asphalt often reads darker than the shoulder.
Snow and ice, briefly
The techniques are the same idea pushed further: everything happens gently, because every input has less grip to work with. Accelerate gently, brake gently, steer gently, and leave multiples of the normal distance. Bridges and overpasses freeze before the road surface either side of them, because cold air moves under them. If you begin to slide, look where you want to go and steer there rather than staring at what you are afraid of hitting.
How the test asks this
Questions in this family are usually built as a comparison: the same action, once in dry weather and once in the stated condition, with the correct answer being the one that reduces speed and increases space. When a stem mentions rain, fog, night or snow, treat it as an instruction to choose the more cautious version of whatever rule is in play. Our items on this topic carry a source line naming the handbook and edition each figure came from, so the numbers can be checked where they matter.
RoadCite is an independent study tool and is not affiliated with any DMV or government agency. Some figures, such as when to dim headlights, are set by state law.
Written for this site · no handbook text is copied; every claim is checked against the official rule it names. Report a mistake.