Automakers' rising interest in making noiseless cars may leave all road safety measure futile, as a new study suggests that vehicles designed to be quieter may trick drivers into thinking they are driving slower than they actually are.
"The main design principle of making cars these days to be as quiet as you possibly can, is actually a real problem for road safety," Discovery News quoted said University of Queensland researcher Mark Horswill as saying.
While automakers reduce the level of noise inside cars fearing that it distracts the driver or interferes with the car's entertainment system, the new findings suggest this is a "questionable" aim.
"By doing that you're systematically removing the cues that people are using to judge their speed. They're feeling more safe and they're getting a sensation of going slower ... but of course the danger is still there," Horswill said.
During the course of study, the participants were presented with pairs of video-based driving scenes, and asked to judge their speed. They heard either in-car noise at the level it occurred in the real world, or reduced in volume by five decibels.
The change in noise was found to shift people's perception of speed, say the researchers.
"When the noise in the car is made quieter, people think they're going about 5 kilometers an hour slower than they would otherwise," said Horswill.
He has revealed that he conceived the idea for this study while driving in a luxury car lent to his research team.
"It was the poshest car we ever had. We found that we were accidentally going way over the speed limit very very fast, but inside the car it was so nice you barely had any sensation of movement at all," he said.
In a previous study also, Horswill had studied people's perception of appropriate speed as they watched video-based driving scenes, from the point of view of the driver.
The participants in that study were asked whether they would go faster or slower than the videoed driver as the noise of the moving car was adjusted.
"When we turned the car noises down, people chose to drive faster," said Horswill.
His studies suggest that given a high performance car, people will drive faster than those driving a lower performance car.
"It's pretty clear that if people are given a car that is more powerful then they will drive it faster and more dangerously," he said.
A research article on the new findings has been published in the journal Perception.