Air Bag On-off Switch problems of the 2007 Toyota Tacoma

Driving my 2007 Toyota Tacoma (v6, 4-wd, automatic, access cab), I experienced sudden unintended acceleration as I was turning from w. Seventh avenue in eugene, oregon onto northbound interstate-105. I was traveling at a safe rate of speed (approx. 20 mph) as I made the turn from the surface street to the left-hand, curving, on-ramp which is the beginning of an elevated freeway structure. It was mid-morning and, although there had been some light rain overnight, the pavement was dry. About halfway through the curve the Tacoma inexplicably accelerated. The rear of the truck swung out to the left at which point it was moving sideways up the on-ramp. The front of the truck jumped the curb and the truck proceeded 20-30 feet sideways along the curb and eventually slid up a concrete wall where the curb transitions to the bridge rail of the elevated structure. Just short of the start of the actual bridge railing the front right wheel and fender struck a tree. At this point, the vehicle bounced back, continued to rotate to the left and came to a rest, straddling the transition wall, having turned 150-170 degrees. At this point I realized the motor was still racing and I switched the engine off. My foot was on the brake pedal. The air bags did not deploy. No one was injured, no other vehicles were involved. Police were called to provide traffic control while the vehicle was removed from the scene but no report was filed. I have lived within two-and-a-half miles of this intersection for more than 36 years. I have been through this intersection thousands of times as a private citizen and in my role as a transportation planner. I have been and am baffled by this incident. The collision damage was repaired. Other than that all parts are original. Original equipment Toyota floor mats had been removed previously.