New siren call of the road for emergency vehicles

British Association

STEVE CONNOR

Science Correspondent

Ambulances, fire engines and police cars will be fitted with a new siren because of accidents involving other road users who cannot tell where emergency vehicles are coming from.

The first ambulances to have the siren will be fitted within a month and the new sound - described as "wow wow wow shish" - should be in widespread use by the middle of next year.

Acoustic scientists who made tests on 200 volunteer drivers said the new sound alerted the public to an emergency vehicle and allowed other road users and pedestrians to assess instantly the direction from which it was travelling.

Deborah Withington, a researcher from Sound Alert, a company set up by Leeds University to exploit the development, said the new siren was a vast improvement on the four different types currently used by emergency services in Britain.

"We tried to create a sound so that, the very first time you hear it, it's enough to recognise where it's coming from," Dr Withington said.

Existing siren sounds were good at alerting people to an emergency vehicle but bad atproviding direction-finding information in the form of a wide spectrum of sound frequencies, she said. In the US, poor direction-finding sirens contributed to 537 injuries and 67 deaths a year from accidents with ambulances and a similar problem existed in Britain.

"A driver may think it inconvenient to hold up an ambulance but for ambulance drivers it is horrendous because it is happening all the time. They are continually having to slow to avoid road users who haven't been able to make the appropriate responses."

Tests on 200 volunteer drivers proved that many had little or no idea where an oncoming emergency vehicle was travelling using existing sirens. "The traditional `nee-nor' was the worst," Dr Withington said."Sound localisation is one of the most complicated things your brain does without you actually ever realising it."

People in West Yorkshire will be first to hear the new siren when it appears on the streets within a month.