Safe Driving: Scanning, Following Distance, Blind Spots, Night, Skids, Rain, Snow, Fog and Wind

Written for aiforu2 as the source for a practice-test bank and the on-device tutor for the California Class C knowledge test. The facts follow the official handbook; the wording is ours.

Source: California Driver's Handbook (DL 600), California Department of Motor Vehicles, 2025 edition, section 8 "Safe Driving", first part (pp. 57–64).

Know your surroundings

Know what is ahead, beside, behind and in your blind spots. Keep your eyes moving and scan the road at least 10 seconds ahead so you have time to react and avoid last-minute moves.

Tailgating blocks your view and leaves no time to react to a sudden brake. Use the three-second rule for following distance. If a vehicle merges in front of you too closely, ease off the accelerator to rebuild the space. Add space ahead when a tailgater is behind you (hold your course and speed, then move right when safe and let them pass) and when following motorcyclists on metal surfaces such as bridge gratings or railroad tracks, or on gravel.

At your sides: stay out of other drivers' blind spots, avoid driving directly alongside other vehicles, make room for vehicles entering the freeway even when you have the right-of-way, keep space from parked cars, and look both ways even where cross traffic has a red light or stop sign.

Blind spots are the areas you cannot see straight ahead or in the mirrors, usually at the sides slightly behind you. Check them by looking over your right and left shoulders through the side windows, turning only your head, never your body or the wheel: before changing lanes, turning at an intersection, merging, backing up, leaving a parking space, parallel parking, pulling from the curb, and opening the door.

Behind you: check the rearview and side mirrors and turn your head whenever you change lanes, check blind spots, slow down, turn into a side road or driveway, stop to park, pull up to or away from the curb, or back up.

Darkness and glare

At night use high beams on open country roads and dark city streets where they are legal, and make sure you can stop within the distance they light; dim them for oncoming drivers. If oncoming lights are too bright, do not look into them: look toward the right edge of your lane, watch the other vehicle from the corner of your eye, and never retaliate with your high beams. In rain use low beams, and never drive on parking lights alone. Motorcycles, pedestrians and bicyclists are much harder to see at night; construction often happens at night, so slow in work zones; after leaving a brightly lit place, drive slowly until your eyes adjust; and when a vehicle with one light approaches, keep as far right as possible, since it could be a bicycle, motorcycle or a car with a headlight out.

Sun glare: keep the windshield clean inside and out, wear polarized sunglasses, keep extra space, keep the visor working and clear, watch for pedestrians you may not see, and avoid driving at sunrise and sunset when you can.

Skids

A skid is one or more tires losing traction so the vehicle slips.

Slippery-surface skids come from ice and packed snow, worse when fast or downhill. Prevent them: slow before intersections and curves (and through sharp curves), avoid fast turns and quick stops, shift to low gear before a steep downhill, and avoid ice patches, wet leaves, oil and standing water. If you skid: ease off the accelerator, do not brake, steer in the direction of the skid, and try to get a wheel onto dry pavement.

Locked-wheel skids come from braking too hard at too high a speed; the car slides regardless of the steering. With four-wheel ABS, press the brake firmly. With rear-wheel ABS (common on light trucks), ease up just enough for the front wheels to roll so you can steer, then stop braking and steer into the skid. With front-wheel ABS, take your foot off the brake to unlock the wheels, steer where you want to go and straighten as the car recovers. Check the owner's manual to learn which system you have. Without ABS, pump the brakes quickly until you reach a safe speed. If the pedal sinks to the floor, pump it gently; if pumping fails, downshift to a lower or neutral gear and try the emergency brake. Dry wet brakes by lightly pressing the accelerator and brake together, only until they dry.

Slippery roads and rain

Rain, snow and mud call for lower speed and more space. Cut your speed by 5 to 10 mph on a wet road, by half on packed snow, and to no more than 5 mph on ice. Shade from trees or buildings hides ice on cold wet days (it freezes first and dries last), bridges and overpasses freeze first, and pavement is very slippery when rain begins, especially after a long dry spell when oil and dust have not been washed away, so slow down at the first drizzle. Use wipers, low beams and the defroster. In a heavy storm you may see no more than 100 feet, and when you cannot see beyond 100 feet it is unsafe to drive faster than 30 mph; stop now and then to clear the windshield and lights. In snow country carry the right number and type of chains.

Hydroplaning is the tires riding on water and losing all contact with the road, when a small steering change, braking or a gust can start a skid. Avoid it by driving slowly, steering around standing water, slowing when the tires slosh, and slowing before changing lanes or direction. If it starts, slow down gradually and do not brake.

Stuck in snow or mud: low gear, wheels straight, gentle accelerator without spinning, forward as far as possible, reverse as far as possible, and repeat the rocking until free; in deep mud or snow put boards or branches under the tires, only with the vehicle stopped.

Floods, wind and fog

Flooded roads can sweep you away, hide debris and hazards, collapse, stall the car, or electrocute with fallen lines, and you cannot judge depth by looking. Find another route; if you must cross, drive slowly and test the brakes afterwards.

High winds are hardest on trucks, campers and trailers. Slow down, hold the wheel firmly, look ahead for debris, do not use cruise control, and consider pulling over until the storm passes.

Fog or heavy smoke: best to postpone the trip. Otherwise drive slowly, use low beams (high beams reflect back as glare), never drive on parking or fog lights alone, be able to stop within the distance you can see, increase following distance, use wipers and defroster, avoid lane changes and passing, and listen for traffic you cannot see. If it gets too thick, pull off the road, turn on the flashers and wait.

Law enforcement traffic breaks

An officer turns on the emergency lights and weaves slowly across the lanes to slow or stop traffic, to clear a hazard, in heavy fog or unusual conditions, or to prevent collisions. Turn on your flashers to warn others, slow gradually to the officer's speed without braking suddenly, keep a safe distance behind the patrol car, and never pass it or speed up until the officer turns the lights off and conditions allow.

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