By Alex LLoyd
https://www.yahoo.com/autos/why-most-drivers-should-brake-with-their-left-foot-115959573142.html

Braking with your left foot has been a contentious subject ever since the birth of automatic transmissions. If you have just two pedals in your car, and presumably two feet to operate them, then why would you not use one for each?
Back in 1964, The New York Times reported that, in at least eight states or Canadian provinces, braking a vehicle with your left foot would result in failure of one’s driving test. And yet at that same time, a further three states actually encouraged the practice. Others were mostly indifferent.
This caused a sharp divide as to which method was correct, and over the last 51 years, that divide hasn’t softened.

Ask any professional racecar driver and the verdict will be unanimous. Braking with your left foot is a safer, more efficient way of driving. For most road users, providing you have basic skills behind the wheel, left-foot-braking is a safer practice for you, too.

Here’s why:
If you’re traveling at 60 mph, covering 88 feet per second, it takes roughly 4.5 seconds to come to a complete stop—or 271 feet, according to Edmunds.com. In the event of an emergency, 132 feet of that stopping distance will be the time it takes for you to perceive the incident followed by the time it takes for you to react to that recognition. In those first 132 feet, then, you won’t even graze the brake pedal.
There’s not much we can do about the 0.75 seconds it takes on average to perceive an incident. While that number may vary slightly between individuals, the length of time it takes to recognize a situation and begin to react is largely unchangeable.
Reaction time is a similar story. But when you consider the additional 0.75 seconds it takes for your right foot to come off the gas pedal, move over to the brake, and then depress said pedal to begin slowing down the car, there is a giant chunk of time we have unnecessarily lost.
According to Evidence Solutions, eliminating that cumbersome process of going from one pedal to the other can save you 60 feet of stopping distance at roughly 55 mph. So, if your left foot were positioned over the brake pedal, using it to slow the car down would eliminate most of those 0.75 seconds you would have otherwise wasted.
That 0.5 of a second or more saved could be the difference between avoiding an accident. How much money have automakers invested over the years in technology such as ABS, brake rotor material and other lightweight components to help shed 60 feet of braking distance? It’s all there to be had, simply by using both feet.

But wait, there’s more: Racecar drivers use left foot braking for the reasons mentioned above. Only for them, the time it takes to switch pedals is time they could still be on the gas accelerating. The other reason is by having the option to overlap both the gas and brake pedals simultaneously during a turn, one can better manage the car’s inherent pitch and roll. This can eliminate many handling deficiencies.