No one number is safe in every situation. Choose your speed based on the weather, the road surface, how far you can see and how heavy traffic is, and remember that driving under the limit can still be too fast in poor conditions.
If a school bus stops on a two-lane road with its red lights flashing, traffic approaching from either direction has to stop and stay put until the lights go off and the bus moves on. Simply slowing down is not sufficient, including when the bus is on the opposite side of the road.
Tip Drivers on the far side of a highway split by a physical divider, such as a raised median, are not required to stop.
The usual guideline is one car length for each 10 mph of speed, or at least 3 seconds: when the red car passes a fixed marker, the blue car should not reach that marker until three seconds have gone by. A 1-second gap is far too close, and 5 seconds is more than the normal minimum, though rain, fog or heavy traffic call for extra room.
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.
When wipers quit during rain or snow, your view is nearly gone. Slow down, and if looking out the open driver's window is your only means of seeing ahead, do so; brake and leave the road at the first safe chance. Once stopped, put on your hazard flashers and wait until the weather clears or the wipers are repaired.
Tight or curving roads, intersections, railroad crossings, and wet or slippery pavement all leave less room for error. A lower speed buys you reaction time and cuts the distance you need to stop.
You must not pass or go around a vehicle that has stopped for people at a crosswalk, because it may be hiding a child who is stepping into the road. Obeying the school speed limit and letting children cross first are things you must do, not things you must avoid.
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.
New Jersey law requires drivers to stop when a frozen dessert truck is stopped with its red lights flashing and its stop arm out, because children may dart toward it or away from it; the exception is a truck on the far side of a safety island on a divided highway.
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.
To indicate a right turn, stick your left arm through the driver's window and bend it up at the elbow so your hand points toward the sky. A straight, extended arm signals a left turn, while an arm bent downward signals that you are slowing down or stopping.
When no signs or signals control an intersection, drivers yield to traffic approaching from their right, and anyone turning left must also give way to vehicles coming toward them. The yellow car has no one on its right, so it goes first; the blue car, with the yellow car on its right, follows; the truck turns left, has the blue car to its right and the yellow car facing it, and so goes last.
Before you back up, change lanes or brake suddenly, check the traffic behind you with your mirrors and by turning your head. Look over your shoulder through the rear window when backing, and check your blind spot before moving into another lane. These are the moments when a collision with someone behind you is most likely: backing takes you toward whatever is back there, and if you change lanes or brake hard, a vehicle coming up behind you may have no room to avoid you.
Blinking your brake lights or turning on the hazard flashers lets the people behind you know early that traffic is stopping for a crash ahead, which gives them room to slow down. These signals warn of danger or an unexpected slowdown; they are not a way to thank another driver or something to use while reversing out of a parking spot.
Tip Hazard flashers are for warning others of a sudden danger, not for excusing double-parking or for ordinary driving.
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.
Under New Jersey law (N.J.S.A. 39:4-128.4), drivers must stop when a frozen dessert truck has its stop signal arm extended and must also stop for anyone crossing the road to reach it. The exception is a divided highway: when a safety island separates your roadway from the truck, you do not have to stop.
School zones commonly carry a 25 mph limit while children are present, for example when a crossing guard is leading students across the street. Where a different limit is posted, the posted sign takes priority, and you should always watch for children stepping into the road.
When a crash cannot be avoided, the goal is to reduce the force of the impact. Something that yields absorbs energy better than a rigid object, a stationary object is less violent to hit than an oncoming vehicle, and a glancing contact is far less dangerous than a direct, head-on hit.
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.
Set the front wheels so that the curb would stop the car if it started to roll: angle them toward the curb if the car points downhill and away from it if the car points uphill. Apply the parking brake every time.
Tip Downhill means wheels toward the curb; uphill with a curb means wheels away from it.
Slippery pavement gives your tires less traction, so lose speed before a curve or intersection rather than while you are in it. Speeding into a curve, or waiting until you are already descending a hill to downshift, makes a skid more likely.
A school bus stopped with its red lights flashing is letting children on or off, and they may walk across in front of traffic. You must halt at least 25 feet away and stay there until the red lights turn off and the stop arm retracts.
New Jersey law (N.J.S.A. 39:4-128.4) requires you to stop for an ice cream truck that is flashing red lights and showing its stop arm, yield to anyone crossing to or from it, and then pass at no more than 15 mph. You may keep going without stopping only on a divided highway where a safety island or raised median separates you from the truck.
Tip Respond to a vending ice cream truck the way you would to a stopped school bus, stopping for its flashing lights unless a divided highway's median keeps you apart from it.
Many states require every occupant to buckle up; in some, adults in the back seat are not legally required to, but a belt protects everyone, so every occupant should wear one. Young children must ride in a child safety seat that fits their age and size.
The headlight requirement begins 30 minutes after sunset, when fading daylight makes it harder for others to see you. Also turn them on at any hour when rain, snow, or fog limits visibility.
Water on the pavement makes stopping take longer, so open up a gap of at least 4 to 5 seconds behind the vehicle ahead. Brake, steer and accelerate gently to avoid skidding.
Tip On wet pavement, plan on about twice your usual following distance so you have room to stop.
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.
The law requires headlights starting 30 minutes after the sun sets and ending 30 minutes before it rises, which means that in the morning you can turn them off when sunrise is half an hour away. Leave them on longer when rain, fog, or snow limits visibility.
After a blowout, hold the steering wheel firmly, take your foot off the accelerator, and keep the car going straight while it loses speed on its own. Braking hard can make you lose control, so stop only after you have eased off the road to a safe spot.
As the picture shows, the mirrors cover the green zones but leave a red blind spot on each side of the car. That is why a lane change needs all three actions: signal, check the mirrors for traffic coming from behind, and glance over your shoulder to catch a vehicle hidden in the blind spot.
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.
Every question in this set has its own page with the correct answer and an explanation.
