Hybrids safer for occupants, not for pedestrians

Recent studies have found hybrids to represent a mixed blessing of increased safety for their drivers, but potentially increased hazard for pedestrians.

Analyzing such data for the first time, the Highway Loss Data Institute found hybrid versions of vehicles compared to an internal combustion-powered counterpart version of the same model in their makers’ lineup are 25 percent less likely to be injured.

The study scrutinized only same-make sibling vehicles, not cars sold strictly as hybrids or electrics such as the Toyota Prius, Honda Insight, Nissan Leaf, Ford Focus Electric and Chevy Volt.

Although they were not looked at, crash test data from these latter vehicles otherwise shows them to be high-scoring as well for the same reason.

What is the reason hybrids are safer to occupants? Extra mass. A hybrid has more weight due to the extra bulk of battery and related components of its sophisticated drivetrain.

“Hybrids on average are 10 percent heavier than their standard counterparts,” said Matt Moore, the data institute’s vice president and author of the study today. “This extra mass gives them an advantage in crashes that their conventional twins don’t have.”

The analysis by the data institute – an affiliate of the Insurance Institute for Highway Safety – examined over 25 hybrid and conventional vehicle pairs made between 2003-2011.

Its findings could be considered empirically obvious to people with a good intuitive grasp of mechanical/spatial relationships. Extra weight carries extra kinetic energy. It is the same principle used to sell heavy SUVs, as their weight is a safety advantage.

Keep in mind the data institute conducted a fairly limited analysis. Also outside its scope were such comparisons as between a mid-sized vehicle and a compact, or compact versus subcompact, etc.

Cars also not studied, like the mid-sized-heavy, but compact-sized Volt for example, have similarly been found to top safety charts among compact class vehicles. The battery alone in the 3,700-plus-pound car weighs around 400 pounds, and extra bulk provides a margin of safety in impacts. The same is true for the Nissan Leaf which weighs over 3,300 pounds.

Flip side

While safety for those inside the car is statistically improved, a second study by the data institute found hybrids could be up to 20 percent more likely than conventional counterparts to injure pedestrians.

Here the cause was their very quiet running.

“When hybrids operate in electric-only mode, pedestrians can’t hear them approaching,” Moore said.

Again, this was with ICE/hybrid sibling pairs, but one could reasonably infer similar concerns for any hybrid or all-electric car for that matter.

In fact, that has already been officially done by way of a congressional mandate to the National Highway Traffic Safety Administration. This ruling was decreed prior to any study such as we are now reporting, and was instead based on lobbied concerns and what some considered common sense.

NHTSA has three years to devise sound alerting standards to make now- near-silent electrified vehicles more noticeable.

The lobbying for this was first started by the National Federation of the Blind whose members noticed a number of near-miss incidents and began pushing years ago for legislation.

Thus far, only Japan has sound-emitting rules in place. The Japanese market 2010 Prius for example has an electric-motor-like humming sound which rises and falls in pitch relative to speed. This equipment is expected to come with the U.S. market 2012 Prius V.

Presently, this sound emitting issue has been approached voluntarily in a few ways by manufacturers. The Volt has a light horn sound meant not to startle, but sound “friendly.” The Nissan Leaf electric car also has a sound to alert pedestrians when it is approaching. Other makers have done similarly.

A unified U.S. standard is expected to be law in a few years. Automakers concerned with liability issues have said they will comply with the federal government’s decision when required, if not before.

Automotive News (subscription req’d.)


  • nycsolar

    They should have articles like this for SUVs. Except that SUVs aren’t even safer for their occupants.

  • Capt. Concernicus

    But I love sneaking up on pedestrians in a parking lot in my Prius. Then I honk the horn to scare them. It’s all good. Haha…

  • Yegor

    Yes, it makes sense.

  • Old Man Crowder

    The weight issue is a no-brainer and I’m a little surprised they had to do a study on it.

    But I hate this debate about artificial noisemakers. Have you ever heard the engine of a Lexus or Infiniti as it trolls through a parking lot? Me neither! Those things are virtually silent to begin with, and then you add in the surrounding ambient noise luxury vehicles are just as quiet as hybrids at low speeds.

    Heaven forbid you open the window and call out a polite “Excuse me!”

  • Yegor

    Then something has to be done with quiet Lexus and Infinity.
    For example a person can start crossing a small residential street between parked along the street cars without looking. A child can run across the street in the same situation. This is very dangerous. I always slow down to 20-25 MPH on this kind of streets but I can see that many people do not.
    Yes, sound warning would be very helpful.
    It can be very nice sound and not annoying – it does not have to travel too far.

  • Old Grumpy

    Yegor: You cannot legislate stupidity! If people run between parked cars they deserve to be hit! It would thin out the (Stupid gene pool). If noise is the trouble then lets make mufflers illegal! All cars should run with straight pipes like a fuel burning dragster! Nothing is perfect yes hybrids are quiet but that doesn’t mean that we have to make them loud we continue to pass laws which are stupid and unnecessary. Lets just drive our hybrids and encourage car manufactures to keep makeing more of them cheaper so evryone can get 50 M.P.G. This just another regulation which will give the manufactuers an excuse to raise the price and rip off the consumer!!

  • ACAgal

    As far as I know, no higher percentages of pedestrians have been injured by quiet cars, this is a thought to be a threat but it is not an actual danger. I once was at the most conjested intersection in Southern California. A truck apparently lost it’s brakes and was gliding down the hill to that intersection. The driver used his horn. Everyone else was using their horns and the intersection was filled with so much noise that few understood death was approaching.
    I had a noisy stationwagon (big engine). Not once did the kids playing ball in the street, scurry to the curb to avoid being by my car, or jaywalker stop walking across moving traffic.

    Both drivers and pedestrians have to be responsible for their action. Engine noise or lack of engine noise makes very little difference, whereas attentive people and the opportunity to respond to dangerous conditions more likely. As a driver, I would like the choice of what my car could sould like, and most days my choice would be Wagner’s “The Flight of the Valkyries”.

  • MrEnergyCzar

    Well written article Jeff. They should make the universal low speed sound be the Blade Runner sound…. Pedestrians also pay attention less than they used to as they are distracted more and rely more on sound than sight….

    MrEnergyCzar

  • simon@syd

    I think it is totally surprising that extra mass should give extra safety. Extra mass means that for a given speed you can’t slow down or change direction as rapidly – so you are more likely to hit rather than avoid. Extra mass means that if you hit an object, extra energy has to be dissipated away from the passengers. Its surely a bit of a problem for other people if extra mass means you are more safe – they are surely less safe as a direct result. Horrible. Id rather drive a light car and not impact on other people so much. And Id really like it if everyone else did the same for me.

  • Mr. Fusion

    Give me a break with the noise makers! Have we become that stupid!? I don’t think so. But the lawyers have definitely become smarter!

    What’s next? Will it will be mandatory to have all cars painted in fluorescent colors because they can’t be seen clearly enough?

  • Van

    Sometimes I do not those that vote for liberals get it. They are the smartest people in the room, and their insight allows them not only to decide how they should live their lives, but also how “the masses” should live too.

    The sliced and diced the data to make their case for man-made global warming.

    They blocked the gas pipeline.

    They blocked 100,000 jobs in NC.

    Notice how they take our freedom, one regulation or statute at a time in the name of food safety or car safety, or for the children, etc and etc. But all the time, the bundlers get kickbacks from Green energy handouts. History tells us what central economic control gives us, misery Soviet Union style. Yet the Amercia people keep voting for Democrats. Amazing.