Although not a common occurrence, your throttle linkage can get stuck, making your car go faster even though you've taken your foot off the gas pedal. Don't panic. Consumer Reports has done extensive testing on how to regain control of vehicles experiencing sudden acceleration.
Drivers who experience sudden acceleration should put the transmission into neutral. They should not pump the brakes. If you put it into neutral, you will retain full steering and full braking capability. This will save your life.
Turn on your emergency lights to warn other drivers.
Tap the gas pedal to try to unstick the throttle linkage.
Check to see if it is caught on the floor mat.
Hook your toe under the pedal to try and free it.
Shift to neutral and apply firm pressure to the brakes without locking the wheels.
Find a safe place to move the vehicle completely off the road.
If your automobile has power steering or locking steering wheel, do not turn off the ignition or you will lose either your power steering, or the ability to steer. Be careful of the vehicles around you as you maneuver to the side of the road.
Have your vehicle checked by a mechanic as soon as possible.