Seeing and Communicating: Mirrors, Blind Spots, Signals
Seeing and Communicating covers what you can see from the cab and what you tell other drivers with lights and signals.
Mirrors and blind spots
- Scan your mirrors every five to eight seconds and before every lane change, turn, and stop.
- Large vehicles carry No-Zones of roughly 20 feet in front, 30 feet behind, and a full lane on each side.
- The test's point of view rule: if you cannot see a truck's mirrors, that driver cannot see you.
Communicating
- Signal early, well before the turn, and cancel it afterward.
- Brake early and lightly so following drivers see your lights before you need full braking force.
- Use four-way flashers when you must drive slowly or when you are stopped and creating a hazard.
- Run headlights whenever wipers are on and whenever visibility is poor.
- Dim high beams within 500 feet of oncoming traffic and within 200 feet of a vehicle you are following.
Worked example
You are in the right lane and want the left. One mirror check shows clear, but a car is sitting beside your trailer. The correct sequence is mirror, signal, mirror again plus a shoulder glance, then move. A single check fails because the blind spot alongside a long trailer is roughly a lane wide and grows as the trailer's rear swings.
Traps that cost marks
- Signaling after the maneuver has already started.
- Assuming a car sees you because you see it.
- Using high beams in fog, rain, or snow, where they reflect back.
- Forgetting to check the mirror on the inside of a turn.