Why Truckers Drift to the Right on the Highway

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 Short Answer

Semi-trucks drift right for several reasons: some trucking companies intentionally align trucks to pull toward the shoulder so drowsy drivers hit rumble strips instead of oncoming traffic. But it can also be caused by highway road crown, crosswinds hitting 500+ square feet of trailer surface, worn tires, misaligned axles, driver fatigue, or momentary distraction. Usually it's not an accident—it's either a safety feature working as intended or a driver correcting for forces you can't see from your car.

Why It Happens: Quick Summary

• Intentional alignment – Some trucks are set up to pull right so drowsy drivers drift toward the shoulder, not into traffic
• Road crown – Highways slope toward the edges for drainage, which pulls heavy trucks right
• Crosswinds – Trailers have 500+ square feet of surface area acting like a sail
• Mechanical issues – Worn steer tires, misaligned axles, or imbalanced loads
• Driver fatigue – Long-haul truckers drive 2,000-3,000 miles per week with inconsistent sleep
• Distraction – Momentary lapses in focus on long, monotonous stretches

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.

Frequently Asked Questions

Why do semi-trucks swerve on the highway?

Most of the time, what looks like swerving is actually a driver correcting for crosswinds, road crown, or a momentary drift. Trucks have a much higher center of gravity and more surface area than cars, so they're affected by forces that you barely notice in a passenger vehicle. If a truck hits the rumble strips and corrects back into the lane, that's usually the system working as designed—not a close call.

Do trucking companies align trucks to pull right on purpose?

Some do. The reasoning is that if a driver falls asleep, the truck will drift toward the shoulder and hit the rumble strips rather than crossing into oncoming traffic. Combined with the technique of leaning on the steering wheel with the right arm, this creates a crude but effective early warning system for drowsy driving.

What are rumble strips for?

Rumble strips are the textured grooves cut into the pavement along highway shoulders and center lines. When tires hit them, they create a loud vibration and noise that alerts drivers they're leaving their lane. For truckers, they're often the last line of defense against a fatigue-related accident.

How many hours do truck drivers drive per week?

Long-haul truckers typically drive 2,000 to 3,000 miles per week. Federal regulations limit driving to 11 hours per day after 10 consecutive hours off duty, with a maximum of 60-70 hours over 7-8 days. Electronic logging devices (ELDs) track compliance, but regulations don't guarantee quality rest—truck stops fill up, schedules get tight, and sleep is often inconsistent.

Is it dangerous to drive behind a semi-truck?

It can be if you're tailgating or sitting in blind spots. Trucks take longer to stop, have limited visibility, and can kick up debris. If you see a truck drifting, give it extra space. Don't pass on the right if you can avoid it, and never linger beside a trailer where the driver can't see you.

Why do trucks drift more when empty?

An empty trailer is lighter and has less traction, making it more susceptible to crosswinds. The trailer acts like a sail—one strong gust can push the whole rig sideways before the driver can compensate. Loaded trucks are heavier and more stable, which is why you'll often see more drifting from empty trailers.

What should I do if I see a truck drifting on the highway?

Give it space. Don't speed up to pass aggressively or honk—the driver is likely already correcting. Stay out of blind spots, avoid tailgating, and pass on the left when it's safe. Most drifting is minor and quickly corrected, but keeping your distance gives both you and the trucker room to react.