Driving a heavy truck

By the end of this topic you can

• You can set a safe following distance based on your vehicle length and speed.
• You can make right and left turns without the trailer hitting curbs or vehicles.
• You can use your mirrors to manage the large blind spots around a truck.
• You can plan speed and gear selection for hills, curves and bad weather.
• You can check routes for low bridges and weight limits before you set off.

What you need to know and understand

• Many state CDL manuals teach a following gap of at least 1 second for every 10 feet of vehicle length below 40 mph, plus 1 more second above 40 mph.
• Truck drivers look much further ahead than car drivers, often 12 to 15 seconds, so they can react early.
• The trailer's rear wheels cut inside the path of the tractor on every turn (off-tracking).
• A truck has large no-zones beside the cab, directly behind the trailer and in front of the bumper.
• Posted truck speed limits and lane restrictions vary by state.
• You are responsible for knowing your vehicle's height and checking clearance; posted heights can be wrong after repaving or snow.

Space all the way round

A 60-foot rig needs at least 6 seconds of gap behind the vehicle ahead at low speed and 7 seconds above 40 mph under the common manual rule, and more in rain, snow or darkness. Keep space to the sides by staying centered in your lane, and avoid driving alongside other vehicles for long. Check your mirrors every few seconds, and before and after every lane change, so you always know what is in your blind spots.

Turning without hitting anything

Because the trailer off-tracks, you must steer the tractor wider than you would a car.

1. Signal early and slow down well before the turn.
2. For a right turn, keep the rear of the trailer close to the curb so cars cannot squeeze in on your right.
3. Drive straight further into the intersection before turning, and swing wide as you complete the turn, not before it.
4. Watch the right mirror for the trailer wheels and for cyclists or pedestrians.
5. For a left turn, reach the center of the intersection before steering, and use the leftmost lane if there are two turn lanes.

Speed, braking and grades

Heavy vehicles take much longer to stop, and an empty truck can actually be harder to stop because its wheels lock more easily. Slow down before curves, not in them: a truck can roll over at speeds below the posted advisory speed. On downgrades, choose a low gear before the hill and use the brakes in short, firm applications. On upgrades, use the right lane and hazard lights if you are going much slower than traffic, where your state allows.

• Do: plan stops early and brake gently to avoid jackknifing.
• Do: watch for runaway truck ramps on steep grades.
• Don't: change gears in the middle of a railroad crossing.
• Don't: drive under a bridge or into a parking garage unless you know your height clears it.

Common mistakes

• Swinging left before a right turn. This invites cars to fill the gap on your right.
• Using a car-length following gap. Base the gap on your vehicle length and speed.
• Taking curves at the posted speed with a high or top-heavy load. Slow down before you enter.
• Not checking mirrors often enough, then changing lanes into a hidden car.

Test yourself: Driving a heavy truck

Answer each question, then read the explanation. Questions come in a random order each time.