Who Needs Sounds of the Road

American Council of the Blind

ACB has been pushing hard to resolve the dilemma of hybrid vehicles and the safety of people who are visually impaired. Hybrids are quieter than their conventional counterparts and in some circumstances fail to supply noises that are sufficiently loud to enable visually-impaired people to navigate streets. ACB supports passage of, the Pedestrian Safety Enhancement Act (H.R. 734, S. 841). This Act would require a Department of Transportation study and establishment of a motor vehicle safety standard for alerting blind and other pedestrians of motor vehicle operation. Both bills have been in committee since early 2009.

Now a National Highway Traffic Safety Report, Quieter Cars and the Safety of Blind Pedestrians: Phase I, posted on ACB’s website, studies the circumstances in which there is a difference between noise levels, whether those differentials impact safety, and the merits of possible countermeasures. Basically, noise levels differ at speeds up to 20 miles per hour. Two approaches for counter measures are discussed, (1) configuring hybrids so that they emit more noise and (2) producing devices that can be carried that warn people who are visually impaired that a quiet vehicle is nearby.

At present, only countermeasures that cause quiet vehicles to emit additional sound come close to meeting the requirements of blind pedestrians. Within this class of countermeasures, there is a fundamental distinction between systems that emit synthetic engine noise at all times when the vehicle is operating at low speeds, and those that emit noise only when triggered by a transmitter carried by blind pedestrians. The former eliminate the need for blind pedestrians to carry special transmitters, and also warn other pedestrians, cyclists and animals of the approach of quiet vehicles, while the latter minimize community noise impact.

The report wisely observes what is true in many circumstances, that universal design measures that assist people with disabilities also help others. The boys and girls who play soccer and street hockey in the middle of the road or who ride bikes without paying too much attention to their surroundings need vehicle noise almost as much as someone who is blind and they are probably less likely to carry a personal noise emitter. The sound must also be recognizable as vehicular noise, the report noted, discussing the disadvantages of personal device sounds.