Driving on a busy s.e. street in washington dc, driving about 20 to 30 mph., heard a noise that sounded like a tire blowing out or some other type of noise emanating from underneath the car. i tried to press the brake, but instead the car accelerated and would not stop. it sped up at least another 15 to 20 more mph, and again, would not stop. there were vehicles in the back, so i could not use the emergency brake or shut the car off. there were also vehicles on the side and in front of my vehicle. i had to make a decision on how to slow the car down without hitting any pedestrians or any other vehicles. decided to try and stop the car by hitting something stationary and ran into a set of steps that belonged to an office building. airbags deployed and two passersby stopped to assist me and my passenger out of the car. we were both transported by ambulance to a hospital with substantial injuries to the chest, rib, neck and back for myself and the passenger. *tr