Airbags are designed with sensors that detect the force of a collision and deploy only when that force is sufficient to cause injury. Even in the case of near-accidents, front airbags may still deploy to protect motorists from brain and neck injuries. For example, when a vehicle rapidly decelerates or abruptly slows down after striking a low object on the roadway, the vehicle’s front airbags may still deploy even though there wasn’t a collision.
Airbags are equipped with a sensor called a MEMS accelerometer, which is a small circuit with integrated micromechanical elements. The MEMS accelerometer moves in response to a vehicle’s deceleration, which then sends a signal to the airbags telling them to deploy.