Stop, Look, and Listen: Quiet Vehicles and Pedestrian Safety
By Deborah Kent Stein
The following article appeared in The Braille Monitor in June of 2005 and has been edited for Fred's Head.
Twenty-five years ago I read a futuristic article about technologies that might some day free the world from dependence on fossil fuels. Among the developments we could expect by the twenty-first century, the article proclaimed, was the electric-powered automobile. Electric vehicles would be powered by a rechargeable battery rather than the traditional gas-burning combustion engine. They would be safe and efficient. Furthermore, such vehicles would alleviate noise pollution along our roads and highways. Electric cars would be virtually silent.
I read the prediction about electric cars with deeply mixed feelings. I applauded the idea of cleaner air and a reduction in greenhouse gases, a benefit to the entire planet. Yet, because I am blind and travel using a long white cane, the thought of silent vehicles filled me with apprehension. Like countless other blind people I walk safely and confidently, judging traffic patterns by sound. Whether I'm crossing a suburban parking lot or a busy avenue in the Chicago Loop, sound gives me the information I need about the vehicles in my environment. How could blind people travel independently in a world filled with silent electric cars?
Troubled, I raised my concerns to a number of blind friends and colleagues. Nearly everyone agreed that silent cars would pose a devastating threat to independent travel for blind people. But again and again I heard the comforting refrain, "They won't let that happen.... They'll figure something out.... If they develop that technology, they'll be sure to make it safe for us." Such thoughts were very heartening. Besides, I had faith in my capacity to find useful cues in my surroundings, no matter how subtle those cues might seem to others. I was convinced that I would be able to hear even the quietest electric car if I paid close attention.
More than two decades have passed since I first read about electric cars, and the future is upon us. Fully electric-powered vehicles have not become popular yet, but a number of cars and pick-up trucks now operate using a combination of electricity and gasoline. These vehicles are known as hybrids because they blend combustion-engine and electric-motor technologies. Excess energy from the combustion-engine energy, which is wasted in conventional vehicles, charges the battery that runs the hybrid's electric motor. When it is in operation, the hybrid vehicle shifts automatically from one power mode to the other. How often and when the vehicle uses electric power varies widely according to model and design. In keeping with those long-ago predictions, the engine is silent when operating in electric-power mode.
I encountered my first hybrid car when Jim, a family friend, dropped by one morning driving a brand-new Toyota Prius. He explained that the Prius uses electric power when running at speeds up to about twenty mph and periodically switches to electric power at faster speeds as well. He added that the car is extremely quiet in its electric mode--so silent, in fact, that car dealers have affectionately dubbed it a stealth vehicle. "It'd be a great burglar's car," Jim said. "You could glide down the street in the dead of night, and nobody would hear a thing."
Eager to prove to myself that I would be able to hear the Prius, no matter what the dealers boasted, I asked Jim to conduct an experiment. He agreed to take the Prius for a short test drive while I listened from the sidewalk in front of my house on a quiet side street. I heard him climb into the car and slam the door on the driver's side. Then I waited, listening for him to start the engine. Nothing happened. I heard only the sparrows chirping in the trees and the distant roar of a lawn mower. At last the car door opened again and Jim asked, "Could you hear it?"
"Hear what?" I demanded. "Why didn't you start up?"
"I did start up," he said. "I drove to the end of the block. Then I backed up and went about three houses past yours. Then I drove back and parked here in front of you again."
I went to the curb and rested my hand lightly on the passenger door. Again Jim started the engine. I felt the car move forward. Uncannily, eerily, it did not make a sound. With horror I realized that I could easily step straight into the path of an oncoming Prius with no hint of peril.
Since that unsettling experiment I have become very aware of the sounds that help me locate the cars in my environment. When a gasoline-powered vehicle is idling, accelerating, or moving at a speed of less than twenty to twenty-five mph, the sound of the engine predominates. On some surfaces, such as a gravel driveway or a rain-spattered street, sound from the tires is also audible at low speeds. When a car moves faster, most sound comes from the tires on the pavement and the rush of wind. At high speeds, therefore, a hybrid such as the Prius can be heard as easily as any other vehicle. The problem arises when a hybrid car, powered by its electric motor, is traveling at slow to moderate speeds--as when it moves along a side street, emerges from a driveway or parking lot, or starts up after a red light or stop sign. Under these circumstances the engine is silent, and there is little or no sound from tire friction or wind resistance. In addition nearly all hybrids come to a full stop at red lights or stop signs, shutting off the engine completely. The engine does not idle, emitting a low, telltale purr. It makes no sound at all. A blind traveler has no indication that a car is present and preparing to move forward at any moment.
Hybrids are not the only vehicles that pose a challenge to blind pedestrians on today's streets. Throughout the automotive industry manufacturers are seeking to make cars quieter. Many gasoline-fueled engines are now almost as quiet as those that use electric power. Manufacturers are even developing tires that produce less friction with the road surface. Such tires will increase fuel efficiency and at the same time cut down on noise.
The increasing prevalence of quiet vehicles may seriously affect the ability of blind people to travel safely. Low-noise vehicles are also likely to affect the safety of sighted pedestrians and cyclists. Sighted people rely on sound to alert them to the presence of vehicles outside their line of vision. Hearing the approach of a car, they can glance in its direction to gauge its speed and location. It is no accident that generations of schoolchildren have been taught to "stop, look, and listen" at every intersection.
Perhaps hybrid vehicles could be engineered so that the radiator fan switches on whenever the car is operating in electric mode. The fan would emit a hum audible to pedestrians. Perhaps a device built into the axle could make a sound as the wheels rotate.
It has also been suggested that blind travelers carry a device that would indicate when a hybrid or other quiet car is in the vicinity. The signal could be auditory or tactile. A tactile signal would have the advantage of not blocking other important sounds in the environment. In addition, it could be of great help to blind people who also have impaired hearing. We question whether any device, however sophisticated, could give us all of the information we are able to gather from listening to traffic sounds. By listening we can tell where a car is, how fast it is moving, whether it is accelerating or slowing down, and whether it is turning or traveling straight through an intersection. Furthermore, we can collect all of this information about several vehicles simultaneously.
We fervently hope that one or more relatively low-tech, inexpensive solutions to the quiet-car problem lie in the future. However, it will require a highly focused and concerted effort to make such solutions a reality. At this stage we are just beginning to raise public awareness that quiet cars pose a safety hazard. Whenever we discuss our concerns with someone for the first time, the response is invariably the same: "It never occurred to me that quiet vehicles might be a problem. The quieter the better, right? But what you're saying makes sense. We need to think about this " Such exchanges are usually followed by a set of crucial questions: "What sort of figures do you have? Have pedestrian injuries increased since cars have gotten quieter? How many people have been killed or injured by quiet cars so far?"
Right now we have no answers to these questions. Extremely quiet cars such as the Toyota Prius still comprise only a tiny fraction of the vehicles on the road. It is currently difficult to isolate lack of sound as a critical factor in pedestrian casualties. We suspect that a link between pedestrian injuries and quiet cars will be more discernible as low-noise vehicles become more common. But in the real world mere suspicion is a fragile basis for policy decisions. We must support logic and intuition with facts and figures.
Before government agencies and the automotive industry will give weight to our concerns, we need data to prove that quiet cars pose a serious problem. We also need to collect accounts of pedestrians and cyclists who have been killed or injured in accidents involving hybrids or other quiet vehicles. We must document as many instances as possible in which a vehicle's low sound level has contributed to an accident. If quiet cars are shown to be involved in more accidents than so-called noisy vehicles, we can build a case for nonvisual safety measures. Tragically, casualties must occur before any steps will be taken to insure safety.
Years ago my friends and I told each other that "they" would protect the safety of blind travelers if electric-powered cars were ever developed. So far "they", whoever they may be, have done nothing of the kind. As blind people, we cannot stand by while our ability to travel safely and independently is whittled away. We must gather the facts, make our voices heard, and take an active role in the quest for viable solutions. We have met countless challenges in the past, and with resourcefulness and perseverance we will meet this one as well.