CDL: Communicating
Communicating: Signaling Your Intentions and Your Presence
Other drivers can't read your mind. They only know what you're about to do if you tell them — through your turn signals, your brake lights, your horn, and even your headlights. This article covers how to communicate your intentions clearly to the drivers around you, and how to make sure your vehicle is noticed in situations where it might otherwise be overlooked.
Signaling Your Intentions
Other drivers have no way of knowing what you're planning to do next unless you tell them. Because of this, signaling clearly and consistently is a core part of safe driving.
Turns
There are three key rules for using your turn signals properly:
- Signal early. Turn your signal on well before you actually turn — this is the best way to discourage drivers behind you from attempting to pass.
- Signal continuously. Since a safe turn requires both hands on the wheel, don't cancel your signal partway through — leave it on until the turn is finished.
- Cancel your signal. If your vehicle doesn't have self-canceling signals, remember to turn yours off once the turn is complete.
Lane Changes
Turn your signal on before you begin changing lanes, then make the move slowly and smoothly. This gives a driver you might not have noticed a chance to react — whether that's honking to alert you or simply avoiding your vehicle.
Slowing Down
Give drivers behind you a heads-up whenever you know you'll need to slow down. A few light taps on the brake pedal — just enough to flash your brake lights — is usually enough warning. Your four-way emergency flashers should be used any time you're driving very slowly or are stopped. Several specific situations call for this kind of warning:
- Trouble ahead: Because the size of your vehicle can make it hard for drivers behind you to see a hazard, flash your brake lights if you spot something ahead that will require slowing down.
- Tight turns: Most car drivers underestimate how slowly a large vehicle needs to go to complete a tight turn. Brake early and slow down gradually to give following drivers fair warning.
- Stopping on the road: Truck and bus drivers sometimes need to stop in the roadway itself — to unload, for example, or at a railroad crossing. Flash your brake lights to warn drivers behind you, and avoid stopping suddenly.
- Driving slowly: Drivers often don't realize how quickly they're catching up to a slow-moving vehicle until they're very close. If you must drive slowly, turn on your emergency flashers to alert those behind you, where it's legal to do so. Flasher laws differ from state to state, so it's worth knowing the rules for wherever you're driving.
One thing you should never do is try to direct traffic yourself — for example, signaling to another driver that it's safe to pass. Doing this could cause a crash, and you could be held responsible, potentially facing significant financial consequences.
Communicating Your Presence
Sometimes other drivers simply don't notice your vehicle, even when it's directly in their line of sight. Taking a few extra steps to make your presence known can go a long way toward preventing a crash.
When Passing
Whenever you're about to pass another vehicle, a pedestrian, or a bicyclist, assume they haven't seen you and could move into your path without warning. Where it's legal, a light tap of the horn — or, at night, flashing your lights from low to high beam and back — can help alert them to your presence. Regardless, always drive cautiously enough to avoid a crash even if they never notice you at all.
When Visibility Is Poor
At dawn, dusk, or in rain or snow, being seen becomes more difficult — and if you're struggling to see other vehicles clearly, they're likely struggling to see you too. Turn on your headlights, not just your identification or clearance lights, and use low beams rather than high beams, since high beams can be bothersome to other drivers even during the day.
When Parked at the Side of the Road
Whenever you pull off the road and stop, turn on your four-way emergency flashers right away — this matters especially at night. Don't assume your taillights alone will provide enough warning; drivers have crashed into parked vehicles because they mistakenly believed the vehicle was still moving normally.
If you're forced to stop on a road or its shoulder, you're required to put out emergency warning devices within ten minutes. Where you place them depends on the type of road:
- On a one-way or divided highway, place your warning devices — flares, triangular reflectors, cones, and similar items — 10 feet, 100 feet, and 200 feet back toward approaching traffic.
- On a two-lane road carrying traffic in both directions, or on an undivided highway, place devices within 10 feet of the vehicle's front and rear corners to mark its location, plus 100 feet ahead of and 100 feet behind the vehicle, on the shoulder or in the lane where you're stopped.
- If a hill, curve, or other obstruction blocks your vehicle from being seen by approaching traffic within 500 feet, move your devices back far enough — beyond that obstruction — so other drivers still get adequate warning.
When you're setting out your warning triangles, hold them between yourself and the oncoming traffic. This keeps you visible to approaching drivers while you're placing them, protecting your own safety in the process.
Using Your Horn
Your horn is another tool for letting others know you're there, and it can help you avoid a crash when used at the right moment. That said, use it thoughtfully — a horn can startle other drivers or pedestrians, and using it unnecessarily can actually create a hazard rather than prevent one.
Clear communication on the road isn't just about following the letter of the law — it's about making sure the drivers, cyclists, and pedestrians around you always know what your vehicle is doing and where it is. Signaling your intentions early and making your presence unmistakable, especially in low-visibility conditions or when stopped, gives everyone around you the time they need to react safely.