The U.S. Department of Transportation had a problem: Toyota customers
were alleging that their vehicle had accelerated unexpectedly, causing death
or injury. The National Highway Traffic Safety Administration (NHTSA) found
some mechanical problems that may have accounted for the accidents—
specifically, a design flaw that enabled accelerator pedals to become trapped
by floor mats—but other experts suspected a software issue was to blame.
Like most contemporary vehicles, Toyotas rely on computers to control many
elements of the car. Congress was worried enough at the prospect of glitches
in millions of vehicles that it directed the DOT to look for electronic causes.