So what if you hit the brakes to slow down and the pedal goes to the floor? What do you do?

1- Begin pumping the brake pedal, you may be able to build up enough pressure in the parking system to slow down a bit, or even stop completely. If you have antilock brakes, you do not normally pump them, but if your breaks have failed, this may work.

2- Do not panic, relax and steer the car smoothly, cars will often safely corner at speeds much higher than you realize or are used to driving. The rear of the car may slip, so steer evenly, being careful not to overcorrect, shift the car into a lower gear" or the lowest if needed" and let the engine and transmission slow you down, however shifting to a certain lower gear depends on your speed, I mean if you are driving fast and shifted the car to the lowest gear, the car may stop stronger than if you are driving at lower speed so be careful.

3- Pull the hand brake, but not too hard. Pulling too hard on the hand brake will cause the rear wheels to lock and then car to spin around. Use even, constant pressure. In most cars, the hand brake (the emergency brake or parking brake) is cable operated and serves as a fail-safe brake that should work even when the rest of the braking system has failed. The car should slow down and, in combination with the lower gear, eventually stop.

4- Blow your horn and flash your lights to get the driver's attention, you don't want to crash into a much slower-moving or stopped vehicle as this is more dangerous than hitting a car with a similar speed, however, you may have no choice, but at least try to hit it square, bumper to bumper, so you don not knock the other vehicle off the road, anyway this is an extremely dangerous maneuver.