Vehicle accidents can occur as a result of defects and are often at the root of an insurance claim. It is not unusual for an insured to blame an automobile accident on a defect related to a vehicle. Insurers hear policyholders bemoaning that their brakes failed, the accelerator stuck, a tire detached, and similar allegations of malfunction. The claims analyst typically investigates the existence of a defect to determine liability or the possibility of subrogation.

The extent of the many potential defects that may exist in an automotive vehicle is beyond the scope of merely one article. Let's examine some case studies of actual accidents involving a defect in the throttle control system.

Below, Figure 1 shows three typical throttle control systems in automobile. The mechanical system is a classic, having been developed since the early days of the automobile. Rod linkages are connected to the throttle plate to actuate the throttle with a return spring whose purpose is to close the throttle plate once the driver's foot is removed. The cable throttle control system is a more recent design whereby a cable controls the throttle via a pulley. A torsional spring returns the throttle plate to a closed position once the driver's foot is removed. The third system is a “fly by wire” or an electronic control system where an accelerator position sensor sends a signal to an electronic control module (ECM), that sends a signal to a throttle position motor, which in turn sets the throttle position.