Feds Say Hybrid Electric Vehicles Too Quiet, Noisemakers Should Be Mandated

by Marc Scribner on January 7, 2013 · 4 comments

in Features, Mobility, Nanny State, Precaution & Risk, Regulation

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Green paternalists often gush about the great potential for hybrid electric automobiles to reduce negative externalities, or social costs, such as local air pollution and greenhouse gas emissions that result from driving. In addition to classic externalities such as crashes, congestion, and air pollution, excessive noise is also one form of social cost, albeit a relatively small cost — remember the “whistle tipped” modified exhaust pipe video that went viral several years ago? The Federal Highway Administration has estimated that noise externalities average 0.06 cents per mile for cars and light trucks, while a paper by Mark A. Delucchi and Shi-Ling Hsu arrived at an estimated cost of 0-0.4 cents per mile. To put this in auto-externality perspective, crashes (which account for three-quarters of automobile social costs) average something like 15 cents per mile.

The National Highway Traffic Safety Administration (NHTSA) is now moving in the opposite direction, and will soon begin a regulatory proceeding that will require that hybrid and electric vehicles emit sounds when they travel at low speeds (this would mean an audible alert whenever the vehicle is started and still stationary, in reverse, or traveling under 18 mph). Presumably, this is to benefit the blind, although NHTSA reveals in its own benefit-cost estimates that bicyclists will benefit more than pedestrians, and cycling is generally not a viable transportation mode for those with poor or no eyesight — not to mention that cycling has a much smaller travel modal share than walking. To many, this would indicate that this isn’t much of a problem in the first place and we live in a world of ever-changing risks best addressed by markets, but those who think as much generally don’t opt for careers as government regulators or special-interest lobbyists.

NHTSA has found that hybrid electric vehicles are more likely to be involved in certain pedestrian or cyclist accidents and says we can expect to save a few dozen lives nationally per year once the regulations come into full force (doubtful). So what do we know about pedestrian and cyclist fatalities when automobiles are involved? The vast majority of pedestrian or bicyclist injury events do not involve motor vehicles. Furthermore, in roadway accident settings, more than half of cycling and about one-third of pedestrian injuries do not involve motor vehicles — meaning that the most serious threats facing many pedestrians and cyclists are their oft-inattentive selves. We also know that pedestrians and cyclists involved in accidents with motor vehicles are far more likely to be intoxicated than those involved in accidents without motor vehicles. It should not be surprising then that a disproportionate number of fatal accidents (as opposed to injurious accidents) involve intoxicated pedestrians and cyclists.

These federally mandated noisemakers will likely do little to save drunk, stoned, iPod-listening pedestrians and bicyclists from their own stupidity inattentiveness. A small class of pedestrians and cyclists may certainly benefit at least initially, although regulation risks locking in inferior technology even once some better safety method or product is developed by automakers. But if we must have this silly nanny-state micromanagement, I hope our regulatory overlords have the sense of humor to make something like this the mandated hybrid alert sound. Unfortunately, NHTSA is not thinking very creatively about the sound possibilities.

Allen January 7, 2013 at 7:50 pm

Why the snide comment about the nanny state saing the pedestrians and cyclists from their own stupidity? You clearly did not read the report and comprehend what the study found. The situations at hand are all ones where it’s most likely that the driver is at fault. The noise is most likely saving them from the drivers recklessness.

Not that I think this justifies the nanny state nor should the Feds be swooping in. There are other ways of addressing this sort of problem that do not involve federal regulations


Similar to pedestrians, in crashes that potentially have occurred at very low speed such as when vehicles are turning, slowing, or stopping, backing
up, or entering or leaving a parking space, the incidence rate of bicyclist crashes involving HEVs was significantly higher when compared to ICE
vehicles. On a roadway was the most common location of bicyclist crashes involving both HEVs and ICE vehicles with no statistically significant
difference. On the other hand, bicyclist crashes involving HEVs at intersections or interchanges were significantly higher when compared to ICE

Marc Scribner January 8, 2013 at 1:35 am

Allen, you’re absolutely correct that the NHTSA report found a statistically significant increase in crash risk among certain low-speed scenarios with HEVs over ICE vehicles. But note that the study in question and all the others referenced fail to take a number of pedestrian/cyclist cognitive state variables into account. We factor in automobile driver intoxication/inattentiveness, so why not pedestrian/bicyclist intoxication/inattentiveness? (I’m a non-driving urban cycling commuter, so this particularly interests me.) If a drunk pedestrian stumbles off a curb directly into the path of a normally traveling car, his cognitive state is largely ignored in crash statistics. I understand that controlling a two-ton projectile is different than walking and bicycling, but non-drivers must be able to assume some responsibility in accidents, right? Yes, I was being snide. But the point I was trying to make was that non-drivers have responsibilities when they enter roadways (that aren’t social vacuums and which have very predictable and orderly operations), which runs against the current fad of demonizing drivers automatically regardless of the circumstances.


JPC January 8, 2013 at 6:59 pm


While technically speaking you’re correct that the study does not explicitly control for factors such as pedestrian intoxication, inattentiveness, etc., the reality is that it most likely doesn’t matter.

Yes, at any given time, some fraction of pedestrians are intoxicated. Some fraction are inattentive. Some fraction are distracted by other stimuli. Some fraction have visual or hearing impairments. Some fraction have mobility impairments. Some fraction are wearing clothing that makes them difficult to see. Some fraction are wearing clothing that makes them easy to see.

All of that adds together and you have a “typical pedestrian model,” which represents an ensemble average of what pedestrians “look like.” Similarly, you can produce a “typical cyclist” model.

The headline result of the experiment is that, in an encounter between a “typical pedestrian” or “typical cyclist” and a vehicle, our “typical pedestrian” and “typical cyclist” are significantly more likely to be struck by the vehicle if that vehicle is an HEV.

That result is significant and correct, unless you are going to postulate that the “typical pedestrian model” is incorrect.

You could do that by providing evidence that, say, pedestrians in the vicinity of HEVs are more likely to be intoxicated than pedestrians in the vicinity of ICE vehicles. You could provide evidence that pedestrians near HEVs are more likely to have visual impairments, or be encumbered by heavy packages, or be distracted by electronic devices, than pedestrians near ICE vehicles. More indirectly, you could argue that HEVs are more likely to be situated in areas where road conditions are such that collisions are more likely, than in areas where ICE vehicles predominate. (Any of these things *could* be true – it’s not outside of the realm of possibility.)

But, absent any evidence of systematic biases of that sort, the result stands.

Marc Scribner January 8, 2013 at 7:18 pm


Thanks for your comment. I don’t dispute the findings that HEVs pose a greater risk to non-drivers that have entered roadways, parking lots, etc. I dispute that this rulemaking is needed in the first place and that waving a magic regulatory wand in an attempt to mitigate risks (large or in this case, small) is an unfortunate political impulse. My final point dealt with the legacy problems of regulation, such as locking in inferior technologies even after improved technologies are available.


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