Sounds that make you drowsy behind the wheel
According to new research from the Swedish National Road and Transport Research Institute, sound waves generated by cars on roadways may cause motorists to get drowsy behind the wheel.
The institute has measured how sound levels and vibrations generated by different kinds of road surfaces can affect drivers.
The study shows a clear relationship between low frequency sound and sleepiness in night drivers. The link is not as strong during daylight.
Some 20 percent of all traffic accidents in Sweden are caused by drowsy drivers, and the researchers hope their study can lead to clearer requirements for sound levels in cars.