Hybrid vehicles and the blind

The National Federation of the Blind has been concerned that blind pedestrians may be in danger because they cannot hear hybrid vehicles running essentially silently in the all-electric mode of operation.

Many kids have already invented a solution to this problem: tape a baseball card to the frame so that it sticks into the spokes of a wheel…

Seriously, though, it is nothing short of amazing how independent a blind person can be with some simple help from society. For example, audible crosswalk signals allow the blind to cross busy streets in many cities. A rational solution to the silent vehicle problem can do much to help maintain this independence.

So far, the National Federation of the Blind has been asking for a minimum sound standard – that a hybrid vehicle always make at least as much noise as a specified sound level. Most agree that adding a noisemaking device would be relatively inexpensive. Ideally, the device would produce a sound which correlates to vehicle performance similiar to the natural sound of an internal combustion engine. Noise which is louder when the vehicle is accelerating or moving faster, but at a speed when tire and wind noise is sufficient to be heard, the noise can be turned down or off. Enough sound to be as easily detected as a conventional vehicle, but no more. Critics say such a requirement is a step backward in reducing noise pollution from motor vehicles; some are quite adamant that no artificial noise be added.

Some propose the installation of rumble strips in the pavement before intersections so that approaching vehicles may be heard. But this kind of noise pollution may be worse than making a hybrid sound like a conventional car. The strips would be expensive to install and maintain. Plus many would not want to live close to them leading to a “not in my back yard” opposition to their installation.

An alternate idea being discussed is to outfit hybrid vehicles with a weak radio transmitter. A blind pedestrian would have to wear a headset to receive this signal and generate an audible indication when a hybrid vehicle is nearby. This technology has some major flaws. The wearer has no way to determine where the car is unless the headset can detect the direction of the radio signal and generate sound in stereo, albeit for a much higher cost. Accurately detecting more than one vehicle may also be difficult. There is the further problem of the headset interfering with hearing conventional vehicles. Additionally, many blind persons rely on a seeing eye dog; providing an extra headset for the animal and teaching it how to use one will be problematic.

I believe the best solution is a cross between the two concepts. Make the radio receiver part of the sound generator on the vehicle. The blind person would wear a radio transmitter to let the car know that sound is needed to warn of its approach. People other than the blind such as bicyclists or the parents of young children may also want to buy transmitters to get the same safety benefit. Highway departments might install transmitters along stretches of roadway where deer tend to cross to protect both the animals and motorists.

There have been reports of sighted pedestrians being surprised when a hybrid vehicle suddenly backs out of a parking space in silence, so the sound may also need to be turned on during some low speed driving situations even in the absence of a radio signal. Better that than have a string of tragic parking lot accidents result in the overreaction of mandating that cars go beep…beep…beep… like a truck when backing up.

Whatever we may end up choosing to do, we need to decide before hybrid and electric vehicles become too numerous.


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