You're cruising down the interstate when the semi ahead of you suddenly veers toward the shoulder. The tires hit those rumble strips, gravel kicks up, and suddenly the truck corrects back into the lane.
It's unsettling to watch, but it happens more often than you'd think.
What's actually going on?
The Intentional Lean
Here's something most people don't know: some trucking companies actually set up their trucks to pull slightly right on purpose.
The logic is dark but practical. If a driver starts to doze off, the truck drifts toward the shoulder instead of into oncoming traffic. The rumble strips or gravel wake them up before things go (literally) sideways.
One former trucker explained it like this: drivers learn to lean on the steering wheel with their right arm. If they nod off, they stop holding tension against that lean. The truck naturally veers right, hits the warning bumps, and jolts them awake.
It's a crude safety system, and it works.
The Alignment Issue
Not all trucks pull right by design. Some just do it because of how they're built or maintained.
Highways are crowned - they slope slightly from the center to the edges so water runs off. That camber affects trucks differently than cars. The higher center of gravity and different suspension geometry make semis more susceptible to that pull.
Add in worn steer tires, misaligned axles, or an imbalanced load, and you've got a truck that wants to wander right no matter what the driver does.
Wind Is a Factor
A semi-truck has over 500 square feet of surface area getting hammered by crosswinds. Even on days that feel calm in a car, gusts can shove a trailer sideways without warning.
Drivers react by steering into the wind. From behind, it looks like they're drifting. They're not—they're fighting to stay centered.
Light loads make it worse. An empty trailer acts like a sail. One strong gust and the whole rig shifts a foot to the right before the driver can compensate.
Fatigue Is Real
Let's not dance around this one. Long-haul truckers drive 2,000 to 3,000 miles a week. The job demands inhuman focus for stretches that would break most people.
Electronic logging devices (ELDs) track hours now, but that doesn't mean drivers get quality sleep. Truck stops fill up fast. Schedules get tight. Shippers take six hours to load cargo that should take one.
And your brain doesn't give you a warning before it shuts down. One second you're fine. The next, you're drifting.
Most drivers catch it. The rumble strips exist for exactly this reason, but it's scary to think about how often it happens.
Distraction Happens
Truckers are human. They glance at the radio. Check their phone. Eat something. Look at a billboard or another vehicle.
A momentary lapse in focus, and the truck drifts right. It's just what happens when you're staring at the same stretch of asphalt for tens of hours.
What You Should Know
If you see a truck drifting, give it space. Don't tailgate semis, even if they maintain a steady speed. Stay out of their blind spots.
And maybe cut them some slack. They're not trying to scare you. They're managing an 80,000-pound machine through conditions most of us never think about.
The next time you see that veer to the right, you'll know: it might be the alignment, or the wind, or it might be a safety feature doing exactly what it's supposed to do.
Or it might be a driver fighting to stay awake for one more mile.
