“Electric vehicles are significantly quieter than standard internal combustion engine vehicles,” the researchers wrote. “Although this is a benefit to the acoustic soundscape, it presents a safety concern, particularly to the vision impaired.”
Prioritizing pedestrian safety
For the study, the team had 16 participants press a button each time they heard an electric vehicle approaching. In some of the trials, the researchers added sounds to the cars to see how this affected the participants’ ability to detect them.
Ultimately, the test came back with mixed results. The researchers learned that it was difficult for the participants to detect the electric vehicles based on sound alone in every trial. This was true even when sound was added to the cars for extra safety.
“All of the cases had mean detection ranges that exceed the National Highway Transportation Safety Administration minimum detection distances,” said researcher Michael Roan. “However, there were cases where probability of detection, even at close ranges, never reached 100%. While the additive sounds greatly improve detection distances over the no sound condition, there are cases where pedestrians still missed detections.”
The researchers noted that countries around the world have different requirements in place regarding the sound of electric vehicles on the road. In the U.S., the National Highway Transportation Safety Administration requirements change depending on the distance and speed of the car; when cars are going faster, they’re required to be detectable from further away.
The researchers hope more work continues to be done on this topic as consumers continue to turn to electric vehicles.