The operation of a car is somewhat reliant on the implication that you have near-full control over where and how fast the car is going. It's through the very careful and precise concert of steering wheel operation and pedal pressure that you can control how the car moves. If that sounds obvious, it's only because we don't think about that stuff until there's a distinct problem with how the car is handling.
If you've spent half your life driving in a particular car, you get used to that car's movement style. When you're on the highway, for instance, you might shift your focus away from steering somewhat when you're on a straightaway. It's in these moments that even slight malfunctions in your car's handling could prove potentially dangerous. All it takes is a slight list to the side while your focus is divided, and you could end up going off-road.
Considering that danger, it's important to be on the lookout for changes in how your car carries itself and remedy them swiftly.
What causes sideways pulling?
If your car is noticeably pulling to one side while you're driving, the cause is usually one of two major culprits.
The first, less severe cause of pulling is a problem with your tire pressure. All four of your car's tires should be inflated to specific PSI levels, as outlined in your owner's manual and the little placard on the driver's side door. If one of your tires isn't inflated to its proper PSI, whether due to an air leak or bad driving habits over time, your car's chassis won't sit evenly on the road, placing more weight on the flatter tire. That imbalance can cause the car to list to the side the flatter tire is on.
The other, more worrisome cause of pulling is a problem with your wheel alignment. Usually, when you let go of the steering wheel while the car is in motion, it automatically returns to a central position. This is because all four of your wheels are centered in uniform alignment. However, if the car is subject to a sudden impact, like going over a deep pothole, the alignment on one of the wheels can be thrown out, causing it to angle to one side while the other wheels are centered.
Fixes and recommendations
If you believe the cause of your car pulling to the side is the tire pressure, that's something you can verify and remedy yourself. Using an ordinary tire pressure meter, which you can get at most grocery stores, hardware stores, and big-box stores, you can check your tires' current PSI levels and compare them to the levels on your pressure placard or in your owner's manual. If any of them seem notably out of tune, just visit your local gas station and use the air pump to fill them to their proper levels. Of course, if one of your tires is actively leaking air, you'll need to visit a mechanic and get it patched.
Speaking of mechanics, if you believe the problem is in your wheel alignment, there's, unfortunately, not much you can do on your own. You can verify a misalignment by checking for a crooked steering wheel, strangely angled wheels, or uneven tire tread wear, but no matter what, this is something only a mechanic can fix. Visit your local garage to have the wheels properly and professionally realigned.