The Tractor-Trailer That Swings Left to Turn Right
You are southbound on a road with two lanes in each direction, stopped at a red light in the right through lane. A tractor-trailer pulls up on your left and puts on its right turn signal. When the light turns green, the truck begins to ease left, its cab swinging toward the lane you occupy, and you can see its trailer wheels are still several feet left of where the turn will end up. A cyclist is riding in the bike lane to your right at about 12 mph, and the crosswalk ahead is empty. Traffic is close behind you.
1. Why is the truck moving left when its signal says right, and what space must you keep clear?
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This is normal off-tracking, not a mistake. A long trailer cuts the corner, so the driver must swing wide left first to keep the trailer's rear wheels from climbing the curb - or from crushing whatever sits to the right of the cab.
The dangerous space is the gap on the truck's right side, between the cab and the curb, and behind the cab along the trailer. That gap looks like an opening and invites drivers to slip through; it is actually the area the trailer will sweep into. Do not enter it, do not creep into it while the light is green, and do not assume the truck is going straight because its leftward motion looks like a lane change.
2. With a truck swinging into your lane on the left and a cyclist in the bike lane on your right, what is the safe action?
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Hold your position behind the stop line and let the truck complete the turn. Your options are constrained in both directions:
- Moving left is impossible - the truck is there.
- Moving right would push you into the bike lane and into the cyclist.
- Accelerating straight through assumes the trailer will not cross your lane, which is exactly what off-tracking means it might.
Wait until the cab and the rear wheels are clear of your lane. Then check the bike lane before advancing. Also watch the truck's trailer over the bike lane: the rear wheels often track across the bike lane on a right turn, so the cyclist is at risk from the same move and may swerve toward you. Give the cyclist room for that swerve rather than sounding a horn or crowding the lane line.
3. What should you not infer from the fact that the truck's signal is on and the light is green?
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Three things the signal does not tell you:
- That the truck will turn immediately. A turn signal can be left on from a previous turn, and a loaded rig needs a wide, slow setup.
- That the truck's direction of travel matches the arrow. The cab swings the opposite way from the turn.
- That the driver can see you. Large vehicles have significant blind spots along both sides and directly behind; sitting beside the cab is sitting where the mirrors do not reach.
Because the light is green, your legal permission to proceed is real - but a green light gives you no immunity from a vehicle already committed to a turn across your path. Judgment beats the signal.