Cruise control was set at approx. 62 mph driving on the Interstate. An exit was taken and coming down the off ramp the truck would not slow down. It seems the brakes did not disconnect the cruise control. Brakes were both pumped and firmly depressed. No response when the gear shift was placed in a lower gear. The electronic system did not shut off after the ignition was placed in the off position. An inspection is warranted, expected and welcome. This was a Sudden Unintentional Acceleration (SUA) incident/accident!!! Numerous other vehicles were placed in danger while crossing a major intersection. Two fire trucks responding to an emergency were passed at 50 miles an hour. Many other occupied vehicles and individuals at an apartment complex were in danger of being killed or injured. As of right now the vehicle has not been inspected by the insurance claims adjuster, so right now it has not been reproduced or confirmed by a dealer or independent service center (but is welcomed to be done). The vehicle or components have not yet be inspected by the manufacture, police or insurance representative (but I would be willing to allow it). There was no warning lamps, messages or other symptoms of the problem prior to the failure. It was totally unexpected and a complete surprise.