A signal that has stayed green for a while could turn yellow at any moment, perhaps just as you arrive. Slowing early gives a heavy vehicle the extra room it needs to stop smoothly if the light changes.
Mirror checks are needed at every stage: before the move, after turning on the signal, right as the vehicle begins to shift lanes, and when the lane change is complete. A vehicle can slide into a blind spot at any moment, so one glance is not enough.
Tip Treat your mirror checks as covering the entire lane change, from before you signal until you are settled in the new lane.
A hazard is anyone or anything on the road, or any road condition, that might become a threat to your safety. Spotting hazards early gives you time to react before they turn into emergencies.
Even properly adjusted mirrors leave blind spots, so check them often and take extra care before changing lanes or merging. Convex mirrors actually make things look smaller and farther away than they are.
Drivers coming up behind a slow vehicle often close the gap faster than they expect, so warn them with your four-way flashers wherever local law allows. Slow traffic belongs in the right lane, and high beams would only glare at oncoming drivers.
That emblem identifies a slow-moving vehicle, such as farm or construction equipment, which typically travels at 25 mph or less. Reduce speed early and pass only when it is safe; the emblem has nothing to do with hazmat loads or police.
Look at each mirror often, but only for a moment, so your attention returns quickly to the road in front of you. Both side mirrors are needed to keep track of traffic around a large vehicle.
Signaling early lets other road users, including cyclists and pedestrians, see your plan in time, and it discourages drivers from trying to pass you as you slow for the turn. Signal every lane change, even in heavy traffic, and use your four-way flashers, not a turn signal, when stopped beside the road.
Telling others when to pass is directing traffic, which you should not do: a driver who relies on your signal may pull out into danger or mistake it for a turn signal. When moving slowly, keep right and, where allowed, warn traffic behind you with your four-way flashers.
A motorcycle can seem farther away than it really is, and its speed is hard to judge, so take a second look before pulling out or turning across its path. Motorcyclists are entitled to a full lane, so never squeeze into the same lane alongside one.
Use your mirrors at every stage of a lane change: before you move over, to be sure the space is open; after signaling, to catch anyone entering your blind spot; as you start across, to confirm the path is still clear; and once you are in the new lane, to check how other traffic reacted.
However well you adjust them, mirrors leave blind spots, especially beside and close behind a large vehicle, so check them often with quick glances. In fact, convex mirrors make things seem smaller and more distant than they are in reality.
Keep your eyes moving: check both sides of the road and shift between the area close to the vehicle and the road far ahead. Fixing your gaze on one side leaves the rest of the scene unwatched, so hazards can build up without you noticing.
Noticing a hazard well ahead of time gives you room to choose an escape path before the situation becomes an emergency. Drivers who see trouble coming can respond calmly rather than being surprised.
Spotting a hazard early gives you precious seconds to decide how you would get out of trouble, for example by slowing down, stopping or steering toward open space, before the situation becomes an emergency.
A box that looks empty could hold something heavy or hide a hazard, so it is best avoided, but only with a gentle, controlled steering input. Braking hard invites a rear-end collision, and an abrupt swerve can cost you control of a large vehicle.
Commercial drivers should look 12 to 15 seconds ahead, roughly one block at city speeds and about a quarter mile at highway speeds. Looking that far down the road gives the driver of a large, slow-stopping vehicle time to spot problems and change lanes or slow down smoothly.
Checking your mirrors should be a constant habit, part of a continuous scan that also covers the road ahead, the lanes on either side, the space behind the bus and the passengers inside.
Skilled bus drivers look ahead the distance they will travel in the next 12 to 15 seconds. At lower speeds in town that is roughly one block, and at highway speed it is about a quarter of a mile.
A convex mirror gives a wider field of view but shrinks the image, so other vehicles seem smaller and farther off than they truly are. Glance at these mirrors often, and judge distances knowing that what you see is nearer than it looks.
A hazard is not yet an emergency, but it can quickly become one. Spotting it early gives you time to decide what you would do, such as where you could steer or stop, if the situation gets worse.
Every question in this set has its own page with the correct answer and an explanation.
