Researchers at Chalmers have investigated how difficult it is for people to identify where warning sounds from electric and hybrid cars traveling at low speed come from, compared to sounds from a combustion engine.
Three different variants of warning signals were used in the tests, which aimed to simulate an environment similar to that in a parking garage. All of them proved to be more difficult to identify than sounds from an exhaust engine.
"As acousticians, we of course think it's good that electric cars are much quieter than regular combustion engines, but it's important to find a balance," says doctoral student Leon Müller, one of the researchers behind the study, in a comment.
In particular, one of the signals, which consists of two different tones, was difficult to locate. None of the over 50 people who conducted the test managed to point out the cars completely correctly.
Wolfgang Kropp, professor of acoustics and co-author, says that electric cars' warning sounds are often tested without background noise, which does not reflect real conditions.
"From a traffic safety perspective, it would be desirable to find a signal that is as effective as possible in terms of detection and localization, but which does not affect people negatively, which our previous research has shown is the case with traffic noise," says Kropp.
The study has been published in The Journal of the Acoustical Society of America.
