LET'S SAVE THE PASSENGER, TOO

Driver's-side air bags, shown to help prevent injury during accidents, are
standard equipment in many new cars. But few models offer passenger-side air
bags. A simple silicon chip may change that. The device, which costs just a
few cents to mass produce, is called a semiconductor bridge (SCB) and was
developed by engineers at Sandia National Laboratories in Albuquerque, New
Mexico.

Currently, a hot-wire system heated by electric current triggers a driver's side
air bag to inflate. It sets off explosive cartridges that produce a heated gas,
which enters the air bag and ignites a propellant that, in turn, releases a
burst of nitrogen to inflate the bag. This process draws a substantial amount
of energy from the battery, and additional air bags would require much larger
initiation systems. But the SCB requires one-tenth of the energy of a hot-wire
system and is one-hundredth its size, says Robert W Bickes, Jr., a physical
chemist at Sandia. Moreover, it heats in microseconds instead of the
milliseconds a hot-wire system requires, and it could be retrofitted into
vehicles that now have only driver's-side air bags, according to Bickes.

"It can literally be used anywhere a hot wire is used," he says.