P.M. BRIEFING : GM Reports Better Electric Car

General Motors Corp. said today that it has developed an electric-powered car with acceleration performance comparable to internal combustion vehicles.

The auto maker said the new car, named Impact, accelerates from zero to 60 m.p.h. in 8 seconds and has a 124-mile range between battery rechargings that would make it suitable for urban driving. Inferior acceleration, range and reduced top speed have all been cited as reasons for the failure of electric vehicles to penetrate beyond a few small specialist markets.

GM Chairman Roger B. Smith unveiled the car at a news conference in Los Angeles, where smog problems and stringent antipollution laws could add to demand for an electric car.

But it may be some time before consumers can buy the Impact. Only one prototype of the car exists, and Smith said extensive marketing tests must still be done to see if GM can profitably produce it.