A maker of switches that turns air bags on and off says federal regulators should require a second light to eliminate confusion among drivers.

The National Highway Traffic Safety Administration requires that the dashboard devices have a removable key and a light that goes on when the air bag is disconnected.But drivers apparently get confused about what the light means, said Steven Long, chief engineer with AirBag Options Inc., which makes air bag switches.

"When you walk into a room and flip the switch, the light comes on," Long said Friday. "People are used to thinking that a light means a device is working."

The company, based in the Fort Worth suburb of Keller, uses a switch with two lights - red for off, green for on - as well as brighter lights.

"Since it's confusing, we're now dealing with the fact that maybe there is a better way to do it," Long said.

No accidents or injuries because of the reported confusion from the single light switches have been reported.

"NHTSA has not heard of any problems, and if companies have, they should notify us immediately," said Rebecca Macpherson, NHTSA attorney.

Since last fall, NHTSA has allowed vehicle owners to get the on-off switches if they or their children are at higher risk of being killed by a deploying air bag. The higher-risk categories include those who must put children in the front seat because they must use every seat, or short drivers who cannot sit at least 10 inches from the air bag.

The agency said it has approved 30,000 motorists to get the switches.