What are they:
Smart restraints provide more consistent protection for people of different sizes and positions in various vehicle crash situations. Traditional safety belts and air bags are set up to provide protection for a range of occupants and conditions by deploying or restraining in a fixed manner.
Advanced restraint systems consider variables such as occupant weight, seating position, safety-belt usage and vehicle deceleration to control belt forces and deploy the air bag optimally. Also, air bags would be designed to not deploy at unoccupied seating positions, where a rear-facing child seat is installed or when an occupant is out of the normal seating position (too close to the air bag).
How they work:
A combination of sensors provides the computer with information about occupant position, occupant weight and seat track position. Accelerometers provide information about the collision. The computer uses this information to decide which restraints should be deployed and in what manner.
Special hardware would be required to tailor deployment of restraints:
Variable deployment air bag actuators allow air bags to fill at different speeds and to different volumes.
Safety belt pretensioners tighten the safety belt at the beginning of a collision.
Safety belt load limiters allow the safety belt to extend with high loads during a collision.
Potential for increased safety and comfort, reduced repair costs.