Concerns about quiet car legislation
Dona Sauerburger
From listserv message 8/22/08


California just passed a bill (California Senate Bill 1174) that, if signed by the governor, will require that the State Energy Resources Conservation and Development Commission convene a committee to research, identify and make recommendations to the Commission on strategies to ensure that all motorized motor vehicles "emit sound sufficient to be heard and localized" by blind pedestrians (it doesn't specify under what conditions the sounds must be heard).

My concern about such legislation is that the issue of quiet cars is just the tip of an iceberg (or a very extreme example) of problems that have been growing regarding street crossing strategies that rely on the sound of cars. As a case in point, research that Rob Wall Emerson and I did two years ago at streets with no traffic control confirms a problem that was raised more than 20 years ago -- that is the fact that in some situations it is not possible to hear cars (even some of the the loud ones!) well enough to know it's clear to cross.

So this issue (not being able to hear traffic / vehicles well enough) is a complex issue, not easily addressed by simple solutions like making cars noisier. We need to study the situation carefully, figure out what are the problems, and what can be solutions.

And in the process we must avoid hasty solutions that turn out to cause problems that we hadn't anticipated. For example, one of the presenters at the NHTSA quiet car summit explained how the level of ambient sound (the sound that remains when it is "quiet") can increase when the sounds of vehicles are increased throughout the community. In Rob's and my research, one of the features that affected the ability to hear an approaching car EVEN MORE THAN the level of noise of the car itself was ... the level of ambient sound! So if we increase the level of ambient sound everywhere by making cars noisier, it is possible we will cause the OPPOSITE effect, and make it more difficult to hear them.

So we need to be cautious here. The alarm and urgency to make cars noisier may cause us to adopt a remedy that at best doesn't help, and at worst makes the problem even worse.

If you follow the progess of the resolutions that the Environmental Access Committee of the O&M Division of AER generated over the last 12 years, you see a change from alarm and urgency ("do something NOW!") to the realization that we need to stop and look at The Big Picture before jumping into hasty solutions.

And I have concerns regarding this particular [California] legislation. The committee is supposed to "research, identify, and make recommendations on strategies to ensure that all [vehicles] emit sound sufficient to be heard and localized by pedestrians who are blind or visually impaired." But our research shows that there are situations -- QUIET situations -- where the vehicles cannot be heard well enough regardless of how noisy they are.

The committee is required to conduct the research in a laboratory to determine the intensity and spectral characteristics of vehicular sounds that are required to accurately align with vehicles, and judge the speed and distance of approaching vehicles. I am skeptical about the validity of conclusions based on laboratory conditions -- we need to do research in the real world.

And the committee seems to be assigned to consider only one solution to the problem -- having all vehicles generate "sufficient" noise. We need to first determine what ARE the problems, and then keep an open mind and a broad perspective to come up with solutions.

Lastly, the committee is given less than a year and a half to assemble the committee, plan and conduct and complete the research including analyzing the data and come up with recommendations, and it is unclear what (and how much) funding will be allocated to this. A year might be sufficient if the problem was a simple one of determining what kinds of noise would work, but this issue is MUCH too complex to come to conclusions so quickly.

As an example, one of the tasks they are to complete is to figure out what kinds of sounds are needed for blind people to determine the speed and distance of approaching vehicles. I participated in a study at Johns Hopkins to just look at whether blind people (and sighted people) CAN determine the speed and distance of approaching vehicles, and it took longer than a year just to plan the study, scout for appropriate places to conduct the research and develop the equipment and instruments we thought were necessary to gather the data, do a pilot, redesign the study and then bring in the subjects and gather the data. The principle investigator still needs to analyze the data and draw conclusions. How in the world do they think that the committee will be able to not only conclude whether blind people can determine speed and distance of approaching vehicles based on their sound alone, but determine what kinds of sounds are required to do it (and conversely, what kinds of sounds are NOT sufficient to do it). It just boggles the mind to think about it.

Similar legislation has been introduced as follows:

  • United States HR 5734
  • Maryland Senate Bill 276 House Bill 1160

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