Transport for London (TfL) has announced plans to trial, for six months from January 2020, an alert at slow speeds on the capital’s latest zero-emission electric bus route.

It has developed the sound, which is played through special speakers inside the front of the bus, to ensure that all road users are aware of electric and hybrid vehicles when they are moving at slow speeds.

Without this warning, these buses are almost silent which could pose a safety risk, particularly for people who are blind or are partially sighted. The pitch of the sound will vary with the speed of the vehicle, helping people know where the bus is and which direction it is going.

The initiative has been developed with input from Guide Dogs for the Blind, London Travelwatch and other key accessibility, walking and cycling groups and the trial on the 100 bus route comes ahead of an artificial sound becoming a regulatory requirement for all new “quiet” running vehicles in 2021.

It will also be trialled on other routes — including the C10 route between Canada Water and Victoria from March, and the P5 route between Elephant and Castle and Battersea from May — as new zero-emission vehicles are introduced.

The sound will play until the bus reaches 12mph, or when it is reversing or stationary at bus stops. When travelling above 12mph, the bus will make sufficient noise to make an alert unnecessary.

The new artificial bus sound is part of an acoustic vehicle alerting system (AVAS) that will be mandatory for all new “quiet” running vehicles after September 2021. AVAS will be consistent across all London bus operators and will be available to transport providers across the UK to ensure that people can detect and recognise a bus regardless of where they are in the UK.

Last reviewed 3 January 2020