Business Notes AUTOS

Since the early 20th century, automakers have been tinkering half seriously with the idea of an electric car. Now, faced with potentially draconian air- quality regulations, automakers may be forced to start building such cars in earnest. Last week General Motors unveiled what it says is the most advanced electric car ever, a two-seater called the Impact.

Designed with the smoggy Los Angeles basin in mind, the battery-powered prototype accelerates from 0 to 60 m.p.h. in 8 seconds -- faster than a BMW 325i -- and has a range of 120 miles between recharges. The Impact would cost about twice as much to operate as an average car, primarily because the batteries would have to be replaced every 20,000 miles.

The Impact is at least partly a public relations gambit, since GM supports more conventional methods of reducing auto emissions. Even so, the company is preparing for the day when smog-choked motorists may decide they prefer whirring electric vehicles to roaring roadsters.