STATUS OF QUIET CARS REPORT by Frederic Schroeder
In recent years, especially over the past decade, consumers have been seeking greener, more fuel efficient cars. In response, as technology has advanced, automobile manufacturers have developed hybrid electric, and more recently, fully electric cars. When operating on electric power, these vehicles are essentially silent, presenting a danger to blind people and other pedestrians.
For the past three years, the United Nations has been working to address the hazard posed by quiet vehicles to the safety of blind people and other pedestrians. The World Forum for Harmonization of Vehicle Regulations (WP.29), "Working Party on Noise" (GRB) created the Quiet Road Transport Vehicle (QRTV) working group charged with developing guidelines for designing alert sound devices. As work progressed on developing voluntary guidelines, in early 2010, the National Federation of the Blind was able to persuade the United States Congress to adopt legislation mandating a minimum sound standard for hybrid electric and other quiet vehicles. As a result of the U.S. law, the United States and Japan proposed that the GRB develop a Global Technical Regulation, rather than voluntary guidelines.
Developing a Global Technical Regulation is complex and will involve reaching international agreement on a number of issues of specific and immediate concern to blind individuals. The following is a brief description of the major issues of particular concern to blind pedestrians:
Key issues
1. Should a minimum sound standard apply solely to hybrid electric and electric vehicles or should it also apply to quiet vehicles using internal combustion engines?
While hybrid electric and electric vehicles are virtually silent at low speeds, internal combustion engines are becoming increasingly quiet, potentially posing the same hazard to blind and other pedestrians as vehicles operating on electric power. For this reason, a minimum sound standard should apply to any quiet vehicle regardless of its power source.
2. Do hybrid electric and electric vehicles need to make an alert sound while temporarily stopped, i.e. while stopped at a traffic light?
It has been argued that a car stopped at a red light does not need to make an alerting sound since the vehicle poses no danger while stationary. Nevertheless, it is important for the blind pedestrian to know of the presence of a vehicle that is temporarily stopped since the vehicle may begin to move at any time. Vehicles operating on electric power begin moving more quickly than vehicles using internal combustion engines, making the need for the pedestrian to be aware of the presence of the vehicle particularly important. If the blind person is unaware of the presence of the car, the blind person may step out unexpectedly just as the driver begins to accelerate.
3. If hybrid electric and electric vehicles are required to emit an alert sound while temporarily stopped, should the same requirement apply to internal combustion vehicles using stop/start technology?
Some newer internal combustion engines literally shut off the engine while stopped rather than idling. When stopped at a red light, vehicles with stop/start technology are silent. Blind pedestrians need to be alerted to the presence of these vehicles for the same reason that pedestrians need to be aware of any vehicle that could begin moving suddenly.
4. Should quiet vehicles come equipped with an on-off switch allowing the driver to disable the alert sound?
It has been argued that there is no need for the vehicle to emit an alert sound when the car is stopped in traffic on a highway with no pedestrian traffic. It has also been argued that an individual coming home to a quiet residential neighborhood late at night should be able to turn off the alerting device so as not to annoy his or her neighbors. Still, allowing a driver to turn the device on and off would compromise the safety of blind people and other pedestrians. The driver, however well intentioned, may forget to turn the device back on or may falsely believe that he or she is in a situation in which the device is not needed.
5. What is the sound level needed to provide reasonable safety?
This question is more complicated than it may first appear. Vehicle manufacturers are under increasing pressure from consumers and governments to minimize vehicle noise. For this reason, it is essential that the Global Technical Regulation not specify a sound level so minimal as to compromise the safety of blind and other pedestrians. Finding a level sufficient to insure safety while not being excessively loud is complicated by environmental noise and other factors. If the alert sound is too loud, people are disturbed. If too quiet, blind pedestrians are placed in life threatening danger. In working to find a reasonable balance, safety should be the highest consideration.
6. What is the cross-over speed, i.e. the speed at which the sound of the tires on the pavement and wind sound emit enough sound that the alert sound is no longer needed?
Sound engineers have determined that vehicles emit more sound as the speed of the vehicle increases. When the naturally occurring sound made by the vehicle reaches the same level as the alert device, the alert sound is no longer needed. This is known as the crossover speed. Determining the correct crossover speed is essential to insuring that blind pedestrians are able to detect the presence of a quiet vehicle from a safe distance.
7. What kind of alert sound or sounds would be easily recognizable as representing a motor vehicle?
From an engineering standpoint, replicating the sound of a conventional internal combustion vehicle is difficult. Still, it is important that the alert sound be one that is intuitively recognizable as coming from a vehicle. If the sound is not identical to the sound of an ordinary car, it must be close enough that the pedestrian will recognize it without the need for significant training.
8. Does the alerting sound need to change in pitch as the vehicle accelerates and decelerates?
It is generally understood that a change in the pitch of the alerting sound should increase as the vehicle increases speed and decrease as the vehicle slows. Today's internal combustion engines naturally change in pitch in response to an increase or decrease in speed. This is known as pitch shifting. Blind people rely on changes in the pitch of internal combustion engines to make judgments about when it is safe to cross a street and to monitor the vehicle's movement. Therefore, the design of an alert sound device must incorporate pitch shifting to indicate changes in the vehicle's speed.
While many issues must still be resolved, the world has taken note of the right of blind people to travel safely and independently, and that means having access to information about the presence and movement of cars and other vehicles. A Global Technical Regulation will help give our human and civil rights to independent travel the weight of law.
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