Ever since I first test drove an electric car – probably about 20 years ago – I’ve been concerned about the fact that, in electric mode, they are silent.
I well remember pedestrians stepping into the path of the car in old Nicosia because they hadn’t heard it coming – and this was long before the seemingly universal habit of walking round town with eyes and concentration on a phone screen, rather than the traffic. Let’s not even mention that with earphones in, either chatting on the phone or listening to music is a pretty silly thing to do if you are a pedestrian or a cyclist in proximity to cars – regardless of whether they are EVs or more traditional combustion engines.
At last the problem is being addressed: from July 1, any electric vehicle (EV) with four or more wheels has to have an ‘Acoustic Vehicle Alert System’ (AVAS) fitted if it wants to be approved for road use in the European Union. If the car is going 20 km/h or slower it must make a continuous noise of at least 56 decibels (but no louder than 75 decibels). Now, that’s not particularly loud, but at least it’s a noise – it’s about the sound level of a dishwasher or an air conditioner. A diesel truck, by comparison, emits about 85 decibels.
Warning sound devices were deemed necessary by some government regulators because vehicles operating in all-electric mode produce less noise than traditional combustion engine vehicles and can make it more difficult for pedestrians, the blind, cyclists, and others, to be aware of their presence.
In the past, warning sounds could be triggered by the driver (like a horn) but now they must be automatic at low speeds. The sounds can vary from clearly artificial (beeps, chimes) to those that mimic engine sounds or tyres moving over gravel.
Japan issued guidelines for such warning devices in January 2010 and the US approved legislation in December 2010. The US National Highway Traffic Safety Administration issued its final ruling in February 2018, and requires the device to emit warning sounds at speeds less than 30 km/h with compliance by September 2020, but 50 per cent of ‘quiet’ vehicles must have the warning sounds by September 2019.
In April 2014 the European Parliament approved the legislation (Regulation (EU) No 540/2014) that requires the Acoustic Vehicle Alerting Systems, which is mandatory for all new electric and hybrid electric vehicles. The new rule established a transitional period of five years after publication of the final approval of the April 2014 proposal to comply with the regulation.
Those five years have now elapsed and the Uniform Provisions Concerning the Approval of Quiet Road Transport Vehicles with Regard to their Reduced Audibility is in force. Existing vehicles are expected to gradually be retrofitted with similar devices.
Several car manufacturers have developed electric warning sound devices, and since December 2011 advanced technology cars available on the market with manually activated electric warning sounds include the Nissan Leaf, Chevrolet Volt, Honda FCX Clarity, Nissan Fuga Hybrid/Infiniti M35, Hyundai Sonata Hybrid, and the Toyota Prius.
Models equipped with automatically activated systems include the 2014 BMW i3, 2012 model year Toyota Camry Hybrid, 2012 Lexus CT200h and all EV versions of the Honda Fit.
Research conducted at the University of California, Riverside in 2008 found that hybrid cars are so quiet when operating in electric mode that they may pose a risk to the blind, small children, the elderly, runners, cyclists, and other pedestrians, as they may have only one or two seconds, depending on the context, to audibly detect the location of approaching hybrid cars when the vehicles operate at very slow speeds.
The EU rules allow car makers to give drivers a choice of engine sounds, so long as they hit certain ‘frequency markers’ and rise and fall with speed.