CDL · General Knowledge · 6 min read
Scanning and Signaling Clearly
- Apply proper visual search techniques by scanning 12 to 15 seconds ahead across different driving environments.
- Manage mirrors and blind spots through pre-trip adjustments and regular observation cycles during transit and maneuvers.
- Communicate vehicle intentions and roadside emergencies using turn signals, brake lights, headlights, horn, and emergency warning devices.
Visual Search: Looking Ahead and Around Your Vehicle
Not looking properly is a major cause of accidents. To be a safe commercial driver, you must know what is going on all around your vehicle at all times. Operating a large vehicle safely requires constant awareness of your entire operating space, because dangerous situations develop rapidly when surrounding traffic changes speed or position without warning.
Most good drivers look at least 12 to 15 seconds ahead while driving. Looking 12 to 15 seconds ahead means looking ahead the distance your vehicle will travel in that amount of time. Because vehicle speed dictates how much ground you cover every second, the physical distance changes depending on where you are driving. At lower speeds, looking 12 to 15 seconds ahead equals about one block. At highway speeds, looking 12 to 15 seconds ahead equals about a quarter of a mile.
Looking 12 to 15 seconds ahead requires shifting your attention back and forth between near and far objects rather than staring fixedly at a single point. Drivers must look ahead for vehicles entering the highway, moving into their lane, or turning across their path. Drivers must also watch ahead for brake lights from slowing vehicles. If a traffic light has been green for a long time, expect it to change, begin slowing down, and be prepared to stop. Failing to look far enough ahead may force you to stop too quickly or make abrupt lane changes, which creates severe hazards for you and surrounding traffic.
Common mistakes
- Focusing on mirrors for extended periods while moving, which causes the vehicle to travel significant distances without the driver observing the road ahead.
- Relying solely on clearance or identification lights during rain, snow, dawn, or dusk instead of activating low-beam headlights.
- Signaling other drivers that it is safe to pass, which commercial drivers must never do.
- Failing to manually cancel a turn signal after completing a maneuver in a vehicle that lacks self-canceling indicators, misleading surrounding traffic.
Key points
- Not looking properly causes crashes; drivers must know what is happening around their vehicle by scanning 12 to 15 seconds ahead (about one block at low speeds or a quarter-mile on highways).
- Adjust mirrors prior to departure only when the trailer is straight, ensuring a small portion of the vehicle is visible as a spatial reference point.
- Convex curved mirrors provide a broader viewing area, but make objects appear smaller and farther away than they really are.
- Check mirrors through quick alternating glances to monitor traffic, blind spots, tires, tire fires, and cargo security without neglecting the forward path.
- Execute lane changes slowly and smoothly, checking mirrors before changing lanes, after signaling, right after starting the move, and upon completion.
- Communicate early by flashing brake lights for slowing or stopping, using low beams in low visibility, signaling turns well in advance, and avoiding unnecessary horn use.
- When stopped on the roadside, activate four-way flashers immediately and place emergency warning devices within ten minutes according to specific roadway spacing rules.
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