Adding Artificial Sound to Electric Vehicles for Safety

Near Accident at Lotus Factory in Hethel England

Electric Vehicles are almost completely silent, except for the sound of the wind, or the wheels on the road. While this may seem like something good, it became a safety concern when some engineers at a Lotus plant in Hethel, England were nearly hit by silent Tesla Roadsters. This is when the idea spawned for adding an artificial noise to the vehicle, to help pedestrians gauge how far away an EV is and how fast it is going (just like with a conventional car). Blind subjects were tested to help determine required volume and frequency levels needed to help people judge EV distance.

Legislators in the USA and Europe Both Considering EV Sound Requirements

In fact, both USA and European legislators are considering minimum noise standards for EVs to promote safety. Lotus is developing sound systems for these types of vehicles that will rattle your ears just like a real v-8 engine. Lotus sees a potential market for the technology of external electric sound synthesis for electric vehicles.

Artificial Sound System Added to Toyota Prius

A prototype was developed for a Toyota Prius which consists of front-mounted speakers and an amplifier which creates realistic engine sounds while the vehicle is in electric-only mode. The level of sound is set to correspond to the throttle position. When the Toyota Prius gas engine fires up, the broadcast shuts down. In order to avoid unnecessary noise pollution, the sound is projected in a narrow path so that only people near the car can hear it.

People Prefer the Futuristic Sound

Surprisingly, testing revealed that people preferred a more futuristic sound (space-ship, star trek like) vs. a more authentic or modern day engine sound (according to Colin Peachy, Lotus's chief engineer for noise, vibration and harshness). Lotus has developed and tested many sounds including more standard internal combustion sounds made to match those of porches, mustangs, etc.

Beta-Test To be Done With UK Supermarket Chain

According to Peachy, aside from pedestrian safety, the engine sounds help keep a driver attentive and override otherwise annoying frequencies like tire drone and wind noise. Very soon the technology will be applied to a series of hybrid delivery cars for a United Kingdom based grocery business.

Tags: Electric Car, Electric Vehicle, Electric Vehicles, Lithium-Ion Batteries, Zero Emissions, Environmentally Friendly, Future of Cars, EV, Hybrid, Chevy Volt Electric Vehicle, Toyota Prius, Dodge Circuit EV, Nissan Leaf EV, BMW Mini E, E-mini, GM Buick Plug-In SUV, EPA MPG