Cutting across a parking lot, gas station, or other property to avoid a sign or signal is illegal. The only exception is when a police officer directs traffic that way.
Total stopping distance is the ground you cover while reacting plus the distance needed to brake, which depends on speed, brakes, tires, and the road surface. Darkness can make hazards harder to spot, but the clock itself does not change how far the vehicle needs to stop.
Tip When judging how quickly you can stop, think about speed, reaction time, brakes, tires, and pavement, not the hour.
A siren or flashing red or blue lights mean an emergency vehicle needs the road. Move to the right edge, stop, and stay there until it has gone by; failing to do so breaks the law and puts lives at risk.
When the wipers quit, you can barely see through rain or snow. Reduce speed, brake, and leave the roadway the moment it is safe to do so. Until you stop, it may help to look through the open driver's window; have the wipers fixed before continuing.
All three situations call for a lower speed: narrow or curving roads leave little room for error, intersections and railroad crossings bring cross traffic and trains, and slick pavement makes stopping take longer. Driving slower buys you extra time to react.
Most states require a parallel-parked car to have its wheels within 12 inches of the curb, and some allow up to 18, so staying within 12 inches keeps you legal in either case. A wider gap leaves the car sticking out into the travel lane, where it becomes a hazard to passing traffic.
Tip A gap of roughly 6 to 12 inches keeps you within the limit while protecting your tires from the curb.
A stop sign, a red signal, and a stop order from an officer directing traffic each require a full stop. The same duty applies in other cases too, such as a school bus with flashing red lights or a train approaching a railroad crossing.
Highway traffic moves fast, so situations change in seconds. Paying full attention, scanning constantly, and being ready for hazards such as debris, stalled cars, or sudden braking all help you avoid a crash.
Headlights are required from half an hour after sunset until half an hour before sunrise, plus whenever rain, fog, snow, or dim light makes people and vehicles hard to see. They help you see the road and help others see you.
Passing must always be done on the paved, main part of the road. Pulling onto the shoulder or dirt edge to get by is never allowed, even next to a vehicle that is turning left.
Without a sign showing otherwise, residential districts carry a 25 mph limit. Homes along the street mean children, walkers and bike riders may appear suddenly, so keep your speed down and stay ready to brake.
Each of these lowers the force of the crash: objects that give way absorb energy, a stationary object adds no speed of its own, and a glancing blow transfers less force than a head-on hit. If a collision is likely, brake hard and steer toward the least harmful option.
Emergency vehicles may stop or turn without warning, and others may be following, so the law requires you to stay back at least 500 feet once one has passed. Trailing it closely is dangerous, and after it goes by you may resume normal driving while keeping that distance.
Every question in this set has its own page with the correct answer and an explanation.
