Electric scooter warning noise research sounds a note of optimism

The University of Salford’s Acoustic Research Center has received additional funding to continue work to develop universal sound for electric scooters, in partnership with Amsterdam-based micromobility operator Dott and the Royal National Institute of Blind People (RNIB).

The new funding supports progress towards universal sound for electric scooters, as part of the “Safe and Sound” project.

Dott (aka emTransit BV) is a European mobility operator with over 30,000 electric scooters in Belgium, France, Germany, Italy, Poland and now the UK. The company is aiming to expand into the UK and recently won a Transport for London electric scooter trial tender. Dott scooters seek to mitigate potential pedestrian safety hazards through the use of an Acoustic Vehicle Alerting System (AVAS) for a separate category of electric scooters.

The three-way partnership between Dott, the RNIB and the University of Salford was launched in 2021 with the report ‘Generation and analysis of artificial warning sounds for electric scooters‘. He supported research on the first feasibility analysis of the use of artificial engine noises on light electric vehicles. The project aims to understand whether artificial engine sounds on electric scooters can improve the audible detectability of these vehicles by people with visual impairments while avoiding contributing to additional noise pollution in our cities.

In response to an RNIB submission, funded by Dott and HEIF, Salford Acoustics have created a series of sounds which have undergone extensive testing at their renowned acoustic research facilities. Preliminary research results indicated that it is possible to improve the visibility of electric scooters using sound without increasing noise pollution in cities.

The first results of the research were the development of a system to generate a warning sound in real time – using a Raspberry Pi computer, in a Python coding environment – depending on the operating conditions of the scooter (e.g. speed).

A microphone array installed under the scooter’s handlebars provided a powerful output with a maximum output level exceeding 50 dBA in the direction of travel above 1000 Hz (at 1.5 m from the rider’s position), the network radiating mainly forwards, as requested by the RNIB.

A laboratory study was also conducted to assess pedestrian awareness of an approaching e-scooter with and without an added audible warning. With the warning sound, the detection time of the approaching scooter has decreased by 0.48 seconds. With the scooter moving at 15mph, this translates to noticing it from a distance of 3.2m farther than when there is no audible warning.

Dr Antonio J Torija Martinez, Principal Investigator of the project at the University of Salford, said: “We are delighted with the progress made on this project. Based on initial research, we have found that adding a well-designed acoustic signal can significantly increase vehicle awareness and ultimately safety.

“The additional funding obtained from the Innovation Strategy Fund enables us to conduct further research on optimizing the acoustic awareness of light electric vehicles that will be effective for people with visual impairments in complex urban environments. Our research will also explore how we incorporate human responses into the design of acoustic solutions for e-mobility.

The ‘Safe and Sound’ project was launched in consultation with several national blind associations across Europe. The first phase of the research will focus on three main areas:

  1. Impact of different sounds on users and the public.
  2. The feasibility and deployment of sounds developed to work in tandem with the vehicle’s hardware capability.
  3. Undertake trials in different European locations.

Maxim Romain, COO and co-founder of Dott, said: “As we strive to provide safe, reliable and sustainable travel in our cities, progress at Salford Acoustics offers encouraging steps towards sound that could help identify vehicles, in a way that respects the environment of our streets. We are committed to supporting further research and working with the wider industry and partners in this project to find a global standard that can make shared electric scooters safer for drivers and pedestrians.

Robin Spinks, Strategic Head of Innovation Projects at RNIB, added: “Lightweight electric vehicles pose a significant safety risk to many visually impaired people. We are delighted to partner with the Safe and Sound project in Salford as we continue to deliver innovative solutions for quiet vehicle detectability.”

The project aims at the deployment of a future global standard on technical standards for light electric vehicles and is constantly seeking collaborations with other partners to complete and improve its research.

The August 2021 report concluded that “a good balance between conspicuity and annoyance can be achieved with a well-designed warning sound”, while ending with the caveat that “further research is needed to design warning sounds with an optimal balance between perceptibility and annoyance”. “.

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