While some gearheads love the sound of an 8-cylinder symphony at their disposal, other drivers prefer an auto that’s as quiet as possible. Indeed, that’s one of the perceived benefits of owning an all-electric vehicle as they are nearly silent at low speeds under light throttle.

Unfortunately for that demographic, there’s another group of people that may ultimately force electric cars to be a bit noisier: those with visual impairments.

As CNET points out, Congress passed the Pedestrian Safety Enhancement Act in 2010 which would require silent-operating vehicles like electrics and hybrids to emit an audible sound when traveling at speeds in which things like tire noise or wind resistance are too quiet for pedestrians to hear.

The National Highway Traffic Safety Administration was supposed to finalize its mandate by January 2014. That deadline was ultimately pushed back to November of this year and yet again, the NHTSA is pushing it back – this time, until March 2016. The administration said additional coordination was needed but failed to elaborate further on the delay.

Once the rules are set, automakers will be given 18 months to comply.

The NHTSA estimates the mandate will reduce the number of pedestrian and cyclist injuries by 2,800 each year. While some automakers like Nissan have voluntarily added such systems to their vehicles, others are concerned that the alerts will be too loud or too complicated. There's also the issue of cost. In the first year alone, implementing the alert system would cost the auto industry an estimated $23 million.