Artificial Car Noise
Nothing seemed to herald the end of the internal combustion engine more than the ability of hybrid cars to leap suddenly to life without the slightest sound. Unfortunately, it turns out that the sweet silence of 21st-century technology has a serious downside: pedestrians and bicyclists are less likely to hear hybrids and electric cars coming their way and are more likely to be clipped or run over. That has prompted a back-to-the-future solution: fake car noise that will alert the unwary.
The evidence that hybrids might be hard to hear coming has been accumulating for years, though it wasn't until the
ILLUSTRATION BY MARC JOHNS National Highway Traffic Safety Administration recently released a study that the full extent of the problem was revealed. Data derived from thousands of accidents revealed that there was no difference between hybrids and conventional vehicles on straightaways. But at intersections, interchanges, parking lots and other places where cars traveled at slow speeds, hybrids proved far more hazardous, with pedestrians and bicyclists getting hit at up to twice the normal rate.
via nytimes.com