Hybrid-electric vehicle warning systems

Some automakers are saying that adding a fake engine noise – or some other warning sound – to plug-in vehicles would subtract that "cha-ching" sound from auto dealers cash registers. The Alliance of Automobile Manufacturers and some automakers outside the group say a mandate for artificial noise makers on electric cars could cause fewer people to buy them, Automotive News says.

Electric vehicle makers like Nissan and Mitsubishi have told the National Highway Traffic Safety Administration (NHTSA) that they fear "lower acceptance" of plug-ins that have noise-making systems to help out blind pedestrians. Vehicle makers also say forcing EVs to make noise when they're not moving would make neighborhoods louder and may be disorienting to blind pedestrians.

In January, NHTSA proposed its rules for plug-in noise-making requirements, saying that electrified vehicles be required to emit certain sounds when traveling 17 miles per hour or slower. The per-vehicle costs for these noise-makers has been estimated to be about $30.