US official warns of risks posed by heavy electric vehiclesDETROIT (AP) — The head of the National Transportation Safety Board expressed concern Wednesday about the safety risks that heavy electric vehicles pose if they collide with lighter vehicles.She noted, by way of example, that an electric GMC Hummer weighs about 9,000 pounds (4,000 kilograms), with a battery pack that alone is 2,900 pounds (1,300 kilograms) — roughly the entire weight of a typical Honda Civic.Even apart from EVs, the nation’s roads are crowded with heavy vehicles, thanks to a decadelong boom in sales of larger cars, trucks and SUVs that’s led to extreme mismatches in collisions with smaller vehicles.Michael Brooks, executive director of the nonprofit Center for Auto Safety, said he, too, is concerned about the weight of EVs because buyers seem to be demanding a range of 300 or more miles per charge, requiring heavy batteries.The consulting firm LMC Automotive has made a more modest prediction: It expects EVs to make up one-third of the new-vehicle market by 2030."