The US NHTSA’s requirement for EVs to make noise below 30kph has been delayed, but automakers must still meet a 50% compliance target in 2019 before the rule comes into full force in 2020
One of the main benefits of electric vehicles, certainly in urban environments, is that they make significantly less noise than their ICE-powered counterparts. However, the whisper-quiet motion of electric motors may in fact prove to be a stumbling block in some markets.
In the US, all new EVs and plug-in hybrid EVs (PHEVs) will be required to make a minimum amount of noise at low speeds by 2020. By September 2019, 50% of automaker’s EV production must emit the noises – a delay from the original plan for 100% compliance in the same year.
EVs will be required to warn others of their presence when travelling at speeds of up to 18.6 miles per hour (30 km per hour).
The intention here is that vehicles should make enough noise to help warn pedestrians and bicyclists of their approach. There is evidence to suggest that quieter cars do result in more accidents – according to a study from the US National Highway Traffic Safety Administration (NHTSA) hybrids were 1.18 times more likely to be involved in a collision with a pedestrian and 1.51 times more likely in the case of cyclists, than ICE vehicles.
NHTSA proposed these long-delayed “quiet car rules” in 2016, although they were first demanded by Congress in 2010.
The response from automakers has been mixed. Some have embraced the requirement – Nissan for example has said that it is developing a sound system dubbed “Canto” which will sing as it moves, seemingly changing pitch as it accelerates. ElecTrans worries it could be incredibly annoying for drivers and pedestrians alike, but you can judge for yourself:
Tesla has suggested some kind of proximity-based sensor system that would aim sound at specific pedestrians, which although smart seems unnecessarily complex.
It is a tricky problem to solve, given that EVs should reduce noise pollution, rather than add to it. In many cases, the solution may simply be to emulate the engine noise pedestrians are used to, which despite being counterintuitive, may be the most straightforward solution. Moreover, there is already an entire industry springing up around the inclusion of modules to make EVs sound different or, indeed to make them sound like engines again.
For a closer look at how they do it, Elektrek points to a recent film accompanying the release of the Jaguar I-PACE. Here, Jaguar sound designer Iain Suffield explains how sounds are added to give an idea of acceleration and performance at higher speeds:
That said, the response from many EV drivers has not been as encouraging, especially as many now prefer the quiet hum of a motor than the roar of an engine.
If the NHTSA regulations are implemented poorly, pedestrians may end up feeling the same, and striking the balance between safety and annoyance is likely to prove difficult.