IRSST - Institut de recherche Robert-Sauvé en santé et en sécurité du travail

Making the Best Use of Backup Alarms

  •   June 18, 2018

Montreal, June 18, 2018 – A new video by the Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST) highlights what factors to take into account to ensure safe use of backup alarms under realistic working conditions. The video is intended for safety officers and users at all companies that have this kind of safety device on their vehicles.

Research funded by the IRSST has produced a report on the state of knowledge on the audibility and sound source localization of the two main types of backup alarms (tonal “beep-beep” and broadband “psht-psht”), as well as on how the positioning of these alarms affects sound propagation behind vehicles.

“Our aim is to promote optimum use of these devices and to minimize the risk of accidents when vehicles are reversing,” said IRSST researcher and lead author Hugues Nélisse.

The video makes four recommendations regarding the ideal conditions for installing and using backup alarms:

  • Place the alarm at the rear of the truck, at a height of between 1 and 2 m, so that it can easily be seen by workers in the hazard zone.
  • Follow standard ISO 9533 when adjusting the sound level of backup alarms for people without hearing loss and without hearing protection, while accounting for all noise sources around the vehicle when measuring the ambient noise.
  • Set a maximum reversing speed of 12 km/h to ensure the correct signal/noise ratio prescribed by standard ISO 9533 and to allow a reaction time of at least 2 seconds.
  • Use broadband alarms in situations where several vehicles will be reversing at the same time, in order to minimize the risks associated with poor ability to locate sound sources.

“The best way to prevent accidents involving reversing vehicles is still to limit reversing as much as possible and to control the number of pedestrians in vehicle-reversing areas by implementing effective traffic plans. Given that backup alarms are still a widely used means of warning people near vehicles that there’s a hazard, we have to use them as effectively as possible, to ensure safety,” said Hugues Nélisse.

To view the video, go to:


Maura Tomi
Communication Advisor