There have been countless rollaway accidents that have resulted due to brake shift interlock failure. Despite drivers putting their vehicle into ‘park’ it somehow shifts gears on its own into reverse and drivers are alarmed when they see it start to roll away. As early as 1914 an interlock device was created to prevent a vehicle from shifting into motion on its own. There have been several different types of interlock variations that many car companies have developed, including a brake transmission interlock, a brake shift interlock, and a starter ignition interlock.

A brake transmission interlock works by applying the brakes automatically if no one is in the driver’s seat. If the safety restraints are not being used the brakes are also automatically applied. A brake shift interlock does not allow the gear shift to move unless the brake is applied. The starter ignition interlock it requires a key and the brake to be applied for a manual vehicle to start. Automatic vehicles must have the gear in ‘park’ or in ‘neutral’ in order for the ignition to be started or for the key to be removed.

While not every car model includes an interlock system it has been estimated that the cost and labor time for the addition is very minimal. This is an easy solution to preventing rollaway accidents and saving the lives of children that are injured while in a vehicle rollaway or that is run over by a rollaway vehicle. The majority of gear shift accidents were due to children moving the vehicle into gear, which a brake shift interlock could have prevented. Most children will not engage the brake simultaneously as they are shifting gears, preventing the vehicle from resulting in a rollaway accident.