New technology could deflate the ballooning criticism that auto air bags pose a hazard for children and some adults, experts say.
Air bags have crashed head-on, recently, with unsettling government statistics - blaming them for the deaths of at least 38 children and 24 adults in low-speed accidents they otherwise would have survived.
Some critics want to disconnect them. Automakers want to improve them and say they have the technology to do it.
At issue are air bags that strike, at 200 miles an hour, children and small adults in unintended and harmful ways.
The National Highway Traffic Safety Administration is considering regulatory changes.
The agency recently allowed manufacturers to install low-power air bags. It must now decide whether to require carmakers to develop "smart air bags" or let the market decide.
Designers put a variety of smart air bags on display in Detroit at the recent annual conference of the Society of Automotive Engineers.
They're designed to know who's sitting where and then regulate how - or if - an air bag will inflate in an accident.
When a small child is sitting up front, a smart air bag may deactivate itself.
When an unbelted passenger sits too close to the instrument panel, a smart air bag would inflate with much less force than today's models.
Many of these new air bags are two years or more from production.
The Mercedes SLK roadster already has a smart air bag system that automatically deactivates the passenger-side if a specially equipped child seat is mounted up front.
But without this safety seat, the Mercedes Smart Seat isn't smart enough to detect a child sitting up front.
Among the newer systems:
*Breed Technologies relies on a switch to measure how close a driver is sitting to the wheel.
*Siemens Automotive projects an electrostatic "curtain" across the front seat to detect how close you sit to the wheel or instrument panel.
*TRW's Advanced Restraint System uses a variety of sensors, including a device that can measure a passenger's weight. Another sensor tells if seat belts are buckled. An ultrasound transceiver detects a passenger's size and position.
Ronald Muckley, a TRW vice president explains that for small women or children, a bag might only partially inflate. For a large adult buckled in and sitting back, it would inflate with full force. If the adult is unbuckled, it might inflate more slowly to give a longer-lasting cushion of support.
*General Motors' Delphi subsidiary puts sensors on the front of the car to detect an impending accident. If a crash is unavoidable, the air bag would begin to inflate before impact, but slowly.
Experts say lots of testing is needed.
"You have to make sure it won't be fooled if someone is sitting in the front seat reading a newspaper," cautions Walter Kosich, a systems engineer at Delphi.