Acoustic Vehicle Alerting System (AVAS) Sound Design
The Acoustic Vehicle Alerting System (AVAS) is a research and sound design project to produce an AVAS sound for electric and hydrogen buses operating in NSW.
Objectives of the research
- Production of a standard, sector-specific AVAS sound for Transport’s growing fleet of electric buses.
- Consideration of road safety for vulnerable road users in the Australian context and support Transport’s 2026 Road Safety Action Plan: Towards zero trauma on NSW roads.
Background
Transport for NSW (Transport) is transitioning its fleet of over 8,000 diesel and natural gas buses to zero-emission technology, as part of the New Electric Bus Program. Electric buses are very quiet at low speed, which may pose a risk to people’s safety, especially vulnerable road users, including people with vision impairment.
In late 2023, Transport proactively introduced a new road safety standard requiring all ZEBs to be fitted with an AVAS. Transport is currently investigating options to introduce a standardised, sector-specific Acoustic Vehicle Alerting System (AVAS) sound for its growing fleet of electric buses in compliance with current road safety standards. A standardised AVAS sound will enhance people’s safety by making it easier for people to identify an approaching bus and distinguish it from other road vehicles.
The project will take into consideration:
- Current standards applicable to the AVAS sound.
- The effectiveness of the AVAS sound in terms of audibility, recognisability, learnability, and other safety-critical features.
- The needs and requirements of a diverse group of key stakeholders.
- The impact of the AVAS sound on our cities' soundscape and how it can contribute to a more pleasant experience for the wider community.
The AVAS sound will comply with current standards and will be developed in collaboration with key stakeholders, including vulnerable road user groups, other state jurisdictions, passengers, bus operators, bus drivers and more.
Next steps
Research is currently underway. Further updates will be provided as this project progresses.
This research is being delivered in partnership with iMOVE and supported by the CRCs program, an Australian Government initiative linking researchers with industry and government. For further information please contact: HF@transport.nsw.gov.au.
FAQS
An Acoustic Vehicle Alerting System (AVAS) is a safety feature installed in electric and hybrid vehicles that generates an artificial sound to alert pedestrians, cyclists, and other vulnerable road users of the presence of an otherwise near-silent vehicle.
Electric and hybrid vehicles operate quietly at low speeds, and an AVAS will enhance road safety by providing an audible warning to help prevent accidents involving pedestrians who may not hear the vehicle approaching.
The AVAS sound is only required at slow speeds up to 20 km/hr under Transport’s road safety standards and the Australian Design Rules (ADRs). At higher speeds, the sound from tires and wind are sufficiently loud as to not require an AVAS.
In late 2023, Transport introduced a new road safety standard (TS 00090:1.0) that applies to all electric buses and Hydrogen Fuel Cell Electric Buses (HFCEB). The standard requires that:
- “ZEBs shall be fitted with an AVAS system designed to meet the technical and performance requirements in section 6 and annex 3 of United Nations Regulation 138”.
- “The AVAS system fitted to TfNSW buses shall have the technical capability to be updated to accept a new sound after entering service to futureproof the AVAS system to allow for adoption of a uniform sound.”
Vulnerable road users (VRU) are considered to include pedestrians, motorcycle riders, cyclists, children 7-years and under, the elderly and users of mobility devices.
The $6.5 billion New Electric Bus Program will deliver thousands of new electric buses and supporting depot infrastructure over the next 10 years, helping to create a more modern, reliable and sustainable bus network for Sydney.
The program will progressively convert 17 existing bus depots to support electric operations, and deliver five new electric bus depots, including at Macquarie Park, in Western Sydney and the Aerotropolis. More than 500 electric buses are already operating in Sydney.
The program supports the NSW Government’s commitment to net zero emissions by 2050, while investing in modern fleet and depot infrastructure to deliver better public transport outcomes for customers and communities.
The transition to electric buses is ongoing and will be progressively delivered across NSW, supporting the continued modernisation of the state’s bus fleet and infrastructure.