In a strange and ironic twist, although automakers have long touted the quiet ride afforded by their luxury models, a recent scientific study published by the Human Factors and Ergonomics Society has raised safety concerns posed by the newer hybrid and electric cars, whose quiet ride has been found to deprive both drivers of other vehicles on the road and pedestrians, particularly the blind, of an important alert to oncoming traffic. These concerns led Rep. Edolphus Towns (D-NY) to introduce a bill entitled the Pedestrian Safety Enhancement Act in April, 2008, which calls for the U.S. Transportation Department to commission a scientific study quantifying the minimal sound that an approaching motor vehicle must give off in order to effectively warn blind people or others as to its presence and proximity, and thereby prevent pedestrian knock-downs or other personal injuries secondary to car accidents.
Interestingly, according to the study, the relative quiet of these newer vehicles poses an additional danger to their drivers: it tends to rob the hybrid vehicle and electric car drivers’ awareness of their own speed, because unlike the gasoline-consuming and conventional transmission engines, these new cars do not make significantly more noise when shifting gears or when achieving higher RPM or speeds.
On the other hand, as noted in the paper, seeking to deliberately introduce more noise is somewhat counterintuitive, because scientists are actively seeking ways to reduce noise pollution. Consequently, some start-up technology companies have proposed some Solomonic solutions. One fascinating approach, introduced by Santa Clara-based Enhanced Vehicle Acoustics, notes that once these cars reach 25 mph, the sound emitted by the tires against the road and the air beating against the cars is sufficient on its own to warn pedestrians of their approach. Consequently, their technology, called PANDA (Pedestrian Awareness Noise-Emitting Device and Application), can be calibrated so that sound is emitted up to the point that the car reaches 25 mph.
The study also focused on some other aspects to this problem: what type of noise should be introduced, and how loud does it need to be? Not surprisingly, they found that engine-like or tire sounds, which were reminiscent of regular cars, were most effective.
Presently, no proposed legislation on this safety issue has been signed into law. However, it is anticipated that this issue will be taken up again by the new Congress.