Michael M. Johnson - Comment

I am regularly a pedestrian, as walk to the Metro and back every day as part of my commute. Thus, I am concerned about pedestrian safety. However, I am also concerned about the noise an electric or hybrid car would make- in particular, the timbre or quality of the sound. While many people live in rural or suburban America where vehicles usually travel at greater than 25 miles per hour (mph), many people live in urban areas where speed limits rarely go about 25 mph. Thus, if careful consideration to the quality of the sound is not considered, you would bath urban dwellers in a cacophony of constant noise. Urban areas are already subject to various vehicle noises from loud beeping for backing-up vehicles, to motorcycle noise to regular vehicle noises. While pedestrian safety is important for human health considerations, so are noise levels. Excessive noise levels reduce property values and can create more stress in people as well as distract from other safety issues. I have worked professionally as a sound engineer and have assisted in the production of music recordings and continue to work with sound and music. I would recommend AGAINST requiring a sound with a specific pitch or tone as heat, age and other variations will lead to minor variances from the original specifications of the microchips used to produce the sound and the tonal sound will eventually go out of tune. Thus, if two vehicles traveled within earshot they would probably not be producing the same exact tone- and we would hear that as being out of tune. This would be most applicable to Alternatives 3, 4 and 5. My recommendation would be to use white or pink noise, which is actually a sound that is comprised of many tones so no specific tone can be distinguished. This is akin to the sound of a wave crashing and receding on the shore, or of wind, or the sound of TV or radio static (a “whoosh” sound). If you wish to alter the tone to produce variance so the listener could distinguish