The Gap on the Right Side of a Turning Tractor-Trailer
You are northbound in the right lane of a four-lane road at 45 mph. Ahead at the next intersection, a tractor-trailer in the right lane has its right turn signal on. As it nears the corner, the cab drifts left, opening a gap of roughly two car lengths between the trailer's right side and the curb. The light is green and you would like to get past before it changes. Just beyond the corner, a cyclist is riding north in the bike lane along the curb.
1. Should you take the gap on the truck's right? Explain what the truck driver is doing and what you would be driving into.
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No. Do not enter that gap.
What the driver is doing: a long trailer cannot pivot around a tight corner on its own track. The driver swings the cab left so the rear wheels - which cut a shorter path than the front wheels (off-tracking) - will clear the curb and any sign or pole on the corner. The swing is the first half of the turn, not an invitation to pass on the right.
What you would be driving into:
- The gap closes as soon as the cab rotates. Two car lengths disappear in about the time it takes the trailer to swing through the corner.
- The area alongside the right side of a trailer is a major blind spot. The driver's mirrors cannot show a car tucked in close to the right side of a long trailer.
- If the gap closes with you in it, the trailer pushes you into the curb, a pole, or the cyclist. There is no escape path.
Correct move: hold back behind the truck, let it complete the turn, and take the right turn or continue straight only after it is fully out of your lane. Waiting one light cycle costs a minute; being in that gap can cost the car.
2. Later you are behind the same type of truck on a 55 mph highway. What following distance should you keep, and how do you turn that into something you can actually check while driving?
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Use time, not car lengths. At 55 mph you cover about 81 feet every second.
- Minimum four seconds in good conditions: 4 × 81 = about 324 feet.
- In rain, at night, or behind a heavily loaded truck, six seconds or more: about 486 feet.
The "one car length per 10 mph" rule is far too short - it would put you around 90 feet at 55 mph, less than half the four-second gap.
How to check it: pick a fixed object the truck passes - a sign, a pavement seam, a mile marker. Count one-thousand-one, one-thousand-two... until you reach it. Fewer than four counts means back off.
Truck-specific reasons for the extra room:
- Loaded trucks need much longer to stop than a passenger car, and if you are tailgating, the truck stops and you do not.
- If you cannot see the truck's mirrors, the driver cannot see you.
- Sitting close puts you in the front no-zone where a sudden slowdown leaves you no reaction time.
3. You plan to turn right into a driveway about 300 feet ahead, and the cyclist is ahead of you in the bike lane going straight. What is your plan?
Read the worked answer
Do not pass the cyclist and then turn across their path - that is the classic right-hook.
Plan:
- Slow early and stay behind the cyclist rather than drawing alongside. At 300 feet you have plenty of room to adjust speed instead of racing to the driveway.
- Signal your turn so the cyclist knows what you intend, and watch for a hand signal or a head check from them indicating they are moving left around a drain or debris.
- Turn only after the cyclist has passed the driveway, or after you have clearly merged behind them and there is no chance of cutting them off.
- If you do pass, give at least three feet of clearance and do not return to the right until the cyclist is well behind you and you can see them in your mirror.
Why it matters: a cyclist going straight in a bike lane has the right-of-way over a vehicle turning across that lane. A right-hook gives the cyclist no time and no escape - the car turns into them from the front-left, where they are already committed. The few seconds you save are the entire margin they need to stop.