You probably have two feet. And your car probably has two pedals. So why don’t we just use one foot for each pedal? The truth is that it is perfectly legal to brake with your left foot. In fact, some race car drivers do. But in your regular commuter, you may find it exhausting for an interesting reason.

In driver’s education class, we all learn to keep our left foot firmly planted on the floor. We are told that proper form is to use our right foot to accelerate. Then, when we need to slow down, we take our right foot off the accelerator and press the brake pedal instead. But even though this is considered “proper” there is no law requiring it.

Many race car drivers–from Formula 1 to NASCAR to rally racing–have abandoned this “proper” method. In most races where they don’t need to use a clutch pedal for every shift, drivers “cover” the brake pedal with their left foot all the time. Then, when they need to slow down, they are a bit quicker to hit the brakes while they are releasing the accelerator. When a hundredth of a second could reshape your career, it makes sense that you don’t want to take the time to move one foot between pedals.

What about the rest of us? In 2015, UCLA psychologist Richard A. Schmidt published an article suggesting that this “two-foot driving style” might be safer. He was looking into the sometimes deadly mistake of getting your pedals mixed up and slamming the accelerator when you’re trying to brake. He suggests that if you were well practiced in using a separate foot for each pedal, you would be less likely to make this mistake.

So why in the world were we all taught to only use our right foot for both the gas pedal and the brake pedal? There are three possible reasons for this method, ranging from “tradition” to still very useful.

First reason: Once upon a time, most cars had a manual transmission and a third pedal for the clutch. The most common way to drive a three pedal car is to reserve your left foot for operating the clutch. Because you never need the accelerator and brake at the same time, your right foot can operate both. So this driving tradition has lived on as a “one-foot driving style” for automatic transmission cars. And that’s a bit silly if you ask me.

Second reason: Two-pedal driving can be tiring and uncomfortable. You may be shocked how far to the right your accelerator and brake pedal are. But if you try to cover one with your left foot, you’ll find yourself sitting sideways. Even if they were spread out, keeping your left foot over the brake pedal without touching the pedal is a bit of a workout. And then when you’re braking, your right foot gets a workout. In one-foot driving, your left foot is at rest and your right foot is always “resting” on a pedal. Sure, it’s working. But at least you don’t need to hold it up in the air like you’re doing the hokie-pokie.

Third reason: Letting your left foot “rest” on the brake pedal while you’re accelerating will wear out your brakes very quickly. And letting your right foot “rest” on your accelerator while you are trying to slow down can damage your car or even cause an accident. But we all get tired and make mistakes. So while two-foot driving may make sense on paper, it opens you up to a lot of risk of messing up.

Next, find out the states where it is legal for passengers to drink while you drive, or see a drift racing instructor explain when left-foot braking might be a good idea during regular street driving: