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The impact of electric vehicles on pedestrians who are blind or vision impaired


Over the past five years or so, electric and hybrid vehicles have come on to the market in increasing numbers, and more are expected to be produced in the future. Green issues are high on the public agenda with environmentally friendly and eco-technologies growing in popularity – to lessen pollution and reduce the use of fossil fuels.

NCBI recognises the environmental benefits of electric and hybrid vehicles and we encourage the increased acceptance of greener vehicles as they play an important role in improving fuel economy and reducing emissions.

However, NCBI is concerned that the introduction of these “silent” vehicles will have safety implications for all pedestrians, including pedestrians who are blind or vision impaired. Most people with impaired vision rely heavily on their sense of hearing when crossing roads and will use the noise of oncoming traffic as a cue for when it is safe to cross a road. There is a greater risk for pedestrians who are blind or vision impaired to be involved in accidents involving “quiet vehicles” because they cannot see and hear the vehicles coming. [Source: An NHTSA study confirmed that hybrid cars are just too quiet for blind people to detect them].

This danger is further increased by the mix of vehicles on the roads, that is, the combination of electric / hybrid cars and conventional cars with internal combustion engines.

Orientation and mobility training offer pedestrians with impaired vision guidance on safe travel techniques. One of these techniques is to listen to the sound of a vehicle’s engine to establish its movement and speed when there are no other safety features provided, such as audio tactile pedestrian crossing points.

Using sound to indicate the location of a vehicle

To interact accurately with the environment, especially those elements involving vehicle movement, vehicles need to indicate not only their location, but also:

  • how far they are away from the person perceiving them,
  • their speed relative to the environmental conditions,
  • their state in terms of acceleration or deceleration and
  • the type and size of the vehicle.

To this end Acoustic Vehicle Alerting Systems (AVAS) must be fitted to otherwise “silent” vehicles.

A traditional combustion engine has a distinct sound. This is familiar to most pedestrians, who can detect its presence and at the same time estimate its type and size. Therefore any sound generated by an electric or hybrid vehicle needs to be distinctive in its presence as a vehicle, along with its speed of travel, distance away and its type and size.

Any sound generated to indicate the presence of a silent vehicle must be discernible in a wide range of environmental conditions – from the quietest country lane to the busiest town centre.

It is helpful for pedestrians to know when vehicles are waiting at traffic lights. If an electric vehicle is stationary at a crossing, can it be heard? This could be important at times when the vehicle is just about to accelerate at speed.

There is an absolute need to generate greater understanding and awareness of the impact of these vehicles on pedestrian safety as well as a need to fit Acoustic Vehicle Alerting Systems (AVAS) as standard, and in a way where they cannot be turned off by the motorist.

Further research into the dangers of electric vehicles

Research from the University of California shows that, in some instances, pedestrians only have one second to audibly identify the presence of an approaching electric vehicle when operating at very slow speed. Findings also proved that electric vehicles must be 74% closer to pedestrians than combustion-engine vehicles for their location to be distinguished audibly [Source: “ – Accessed 12 February 2013].

Consultation with the motor industry

There are concerns that vehicle manufacturers could be eager to have their own unique AVAS for their brand, which could result in the provision of multiple sounds creating a lot of confusion for pedestrians.

The European Blind Union (EBU) has consulted two leading car manufacturers, Nissan and Renault, to find out what they are doing in terms of provision of audio sounds in their electric vehicles. The EBU further called for a ban on a pause switch which would allow the driver to temporarily stop the AVAS.
Nissan gave the EBU a demonstration of sounds incorporated in their first generation electric cars launched in Europe, Japan and the United States. Three sounds have been integrated into the vehicle, in consultation with United States National Federation of the Blind and the blindness organisations in Japan. These include: a start-up sound, a slow running sound as the vehicle starts up and accelerates or as it slows down or decelerates and when the vehicle is reversing.

Renault however demonstrated a number of sound-combinations to the EBU.

The EBU has concluded that considerable work and trial still needs to be undertaken by both these manufacturers to ensure that a distinct audible sound(s) is chosen and that a standardisation of sound(s) be devised.

International Perspective

United States

The United States have embraced the issue of pedestrian safety with the introduction of the Pedestrian Safety Enhancement Bill, 2009. Under this Bill, the National Highway Traffic Safety Administration, blindness organisations and automobile manufacturers have set a minimum noise standard and determined which sounds will be permitted. There is also a stipulation that the sound should occur automatically and be standardised by automakers and dealers.


The Japanese government has also drawn up legislation to make electric cars emit a sound. A Ministry of Transport panel worked on guidelines for a minimum noise level for such vehicles, inviting ideas from the public for a standard warning noise.

United Kingdom

The UK Department of Transport are commissioning research which will gather statistics on accidents involving electric vehicles with pedestrians who are blind or vision impaired. These statistics will be used to compare the noise characteristic of an electric vehicle and a vehicle fitted with an internal combustion engine. The findings will inform the Department about what sort of sound should be fitted to electric vehicles, for example. Guide Dogs UK and the Royal National Institute for the Blind are already working with manufacturers, for example, Lotus Engineering, in order to develop an external sound technology for use in electric vehicles.


On the 12 April 2010, the Irish Government announced that they had partnered with Electric Ireland (ESB) and an alliance between Renault-Nissan in order to position Ireland as a European leader in electric transport. This included the development of a nationwide electric car charging infrastructure, the supply of electric cars by the Renault-Nissan Alliance from 2011, as well as Government policies and incentives to facilitate the widespread use of such vehicles.

Recent Progress

Legislative action to address the issue of quiet vehicles is taking place currently at two different levels.
Firstly, for the past three years, the hazards posed by quiet vehicles to the safety of blind people and other vulnerable road users have been addressed by the UNECE Quiet Road Transport Vehicle Working Group (QRTV) – an informal working group established by the Working Party on Noise (GRB) which is a subsidiary body of the World Forum for Harmonization of Vehicle Regulations. The QRTV working group has been mandated by the GRB to draft recommendations for a Global Technical Regulation (GTR) regarding a sound device for quiet vehicles which would alert pedestrians to the presence of a quiet vehicle and its modes of operation.

In February 2012 the QRTV working group submitted its final report [Source: Draft Recommendations for a Global Regulation Regarding Audible Vehicle Alerting Systems for Quiet Road Transport Vehicles, submitted by the Informal Working Group on Quiet Road Transport Vehicles, June 2012] to the GRB Assembly covering the findings and recommendations regarding the future development of a UN GTR that would specify the applicability and performance of an “Audible Vehicle Alerting System” (AVAS). A kick-off meeting of the reestablished QRTV working group was convened in July 2012 to discuss the way forward to adopting a GTR. An UNECE Regulation in force would bind legally all contracting parties which sign this regulation.

At European level, in a vote on 6 February, 2013, the European Parliament adopted an amendment requiring car manufacturers to equip their ‘silent’ cars with an Acoustic Vehicle Alerting System (AVAS), which will ensure that these vehicles are heard by people with sight loss.


NCBI is not requesting major changes to the design of vehicles but simply an increase in their audibility. The benefits of an external sound technology to alert pedestrians to the presence of electric vehicles increases pedestrian safety and at the same time, retains vehicles environmental benefits.


1. Incidence of Pedestrian and Bicyclist Crashes by Hybrid Electric Passenger Vehicles. Technical Report. Published by the National Highway Traffic Safety Administration, September 2009.
2. Quieter Cars and Safety of Blind Pedestrians. Phase I, published by the National Highway Traffic Safety Administration, April 2011.
3. Hybrid Cars Are Harder to Hear, Newsroom University of California, Riverside “ – Accessed 12 February 2013.
4. Draft Recommendations for a Global Regulation Regarding Audible Vehicle Alerting Systems for Quiet Road Transport Vehicles, submitted by the Informal Working Group on Quiet Road Transport Vehicles, UNECE June 2012.

Last updated February 2013