Hybrid models don't just have the advantage of fuel economy over their gas-only siblings – it appears that batteries and electric motors make them safer as well. To find this out, the Highway Loss Data Institute studied 25 2003 to 2011 vehicles that featured both conventional and hybrid powertrains (example: Honda Accord and Honda Accord Hybrid). The Toyota Prius and Honda Insight were not included in the study since neither vehicle has a conventionally-powered counterpart.

The data shows that occupants are 27 percent less likely to be injured if they're in the hybrid version of the vehicle. There are several reasons why the hybrid is safer, but the biggest factor is weight. Heavier cars are safer than lighter vehicles, since the added mass means that the heavier vehicle will transfer force to the lighter vehicle. That's good for occupants and insurance companies, as the hybrids need 25 percent less personal injury protection than their conventional counterparts.

But while hybrids have proven to be safer than their non-hybrid counterparts, the story isn't as good for pedestrian crashes. HLDI finds that hybrid vehicles are 20 percent more likely to be involved in pedestrian crashes with injuries. The study claims that pedestrians might get involved in more accidents with hybrids because they can't hear the cars when they're in electric-only mode. We'd add that low rolling resistance tires often inhibit stopping ability, and the heavier hybrids are also slower and less maneuverable than their non-hybrid counterparts.

Hit the jump to read over the full details of the study.
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ARLINGTON, VA - Hybrids have a safety edge over their conventional twins when it comes to shielding their occupants from injuries in crashes, new research by the Highway Loss Data Institute (HLDI), an affiliate of the Insurance Institute for Highway Safety, shows. On average, the odds of being injured in a crash are 25 percent lower for people in hybrids than people traveling in nonhybrid models.

"Weight is a big factor," says Matt Moore, HLDI vice president and an author of the report. "Hybrids on average are 10 percent heavier than their standard counterparts. This extra mass gives them an advantage in crashes that their conventional twins don't have." He notes that other factors, such as how, when, and by whom hybrids are driven, also may contribute. Researchers included controls to reduce the impact these differences may have had on the results.

The new finding is more good news for green-minded drivers who don't want to trade safety for fuel economy. Not so long ago, car buyers had to choose between the two because fuel-efficient cars tended to be smaller and lighter. Now, consumers have more options than ever when it comes to picking an environmentally friendly - and crashworthy - vehicle.

"Saving at the pump no longer means you have to skimp on crash protection," Moore says.

In the study, HLDI estimated the odds that a crash would result in injuries if people were riding in a hybrid versus the conventional version of the same vehicle. The analysis included more than 25 hybrid-conventional vehicle pairs, all 2003-11 models, with at least 1 collision claim and at least 1 related injury claim filed under personal injury protection or medical payment coverage in 2002-10.
Estimated injury odds under collision
& personal injury protection coverage
Estimated injury odds under collision and personal injury protection coverage
Estimated injury odds under collision
& medical payment coverage
Estimated injury odds under collision and medical payment coverage

Collision coverage pays to repair or replace an at-fault driver's vehicle after a crash with an object or another vehicle. Personal injury protection, or PIP, pays medical expenses for injuries insured drivers and other people in their vehicles sustain in a crash, no matter who is at fault in the collision. Medical payment, or MedPay, covers treatment costs when insured drivers or their passengers are hurt in crashes when the driver is at fault. PIP coverage is sold in states with no-fault insurance systems, and MedPay coverage is sold in tort states.

Hybrids' injury odds were 27 percent lower than their standard counterparts for collision claims with a related PIP claim and 25 percent lower than their twins for collision claims with a related MedPay claim.

Crash physics: It's well known that size and weight influence injury likelihood. In a collision involving two vehicles that differ in size and weight, the people in the smaller, lighter vehicle will be at a disadvantage. The bigger, heavier vehicle will push the smaller, lighter one backward on impact. This means less force on people in the heavier vehicle and more on the people in the lighter one. Greater force means greater risk, so people in the smaller, lighter vehicle are more likely to be injured. Even in single-vehicle crashes, heavier vehicles have an advantage because they are more likely to move, bend, or deform objects they hit.

Even with advances in occupant protection, larger vehicles still are safer choices than smaller ones. That's why downsizing vehicles to improve fuel efficiency has traditionally resulted in safety trade-offs. The trend among automakers nowadays is to boost fuel economy by designing more efficient internal combustion engines and by adding hybrids to their fleets.

Although hybrids share the same footprint and structure as their conventional counterparts, they outweigh them because of the added heft of battery packs and other components used in dual-power systems. At about 3,600 pounds, a hybrid Honda Accord midsize sedan, for example, can weigh as much as 480 pounds more than a conventional Accord. A hybrid Toyota Highlander, a midsize SUV, weighs about 4,500 pounds, compared with about 4,170 pounds for the conventional Highlander.

The Toyota Prius and Honda Insight were excluded from the study because they are only sold as hybrids. The analysis controlled for calendar year, rated driver age and gender, marital status, vehicle density (number of registered vehicles per square mile), garaging state, vehicle series, and vehicle age.

Hybrids and pedestrians: A separate analysis by HLDI shows that hybrids may be as much as 20 percent more likely to be involved in pedestrian crashes with injuries than their conventional twins.

Analysts examined how frequently injury claims were filed for 17 hybrids and their nonhybrid counterparts when there was no related collision or property damage. Studied vehicles included 2002-10 full hybrid models and their standard twins during 2004-2010 calendar years, totaling 25,382 bodily injury liability claims and 2.9 million years of exposure.

Bodily injury liability coverage insures against medical, hospital, and other expenses for injuries that at-fault drivers inflict on occupants of other vehicles or others on the road.

Claim frequencies were defined as claims per 1,000 insured vehicle years (an insured vehicle year is 1 vehicle insured for 1 year or 2 for 6 months each, etc.). The analysis controlled for calendar year, rated driver age, rated driver gender, marital status, risk, registered vehicle density, garaging state, vehicle series, and vehicle age.

"When hybrids operate in electric-only mode pedestrians can't hear them approaching," says Moore, "so they might step out into the roadway without checking first to see what's coming."

It's a problem that's cropped up as hybrids have become more common, and it's one the National Highway Traffic Safety Administration is working to address. Earlier this year Congress gave the agency three years to come up with a requirement for equipping hybrids and electric models with sounds to alert unsuspecting pedestrians.

Moore points out that HLDI can't definitively tell from the claims data that a crash involved a pedestrian. Likewise, some pedestrian crashes may have been unintentionally excluded. For example, a crash in which a person was struck and injured and the vehicle also was damaged would have been omitted because a collision claim would have been filed for the damaged vehicle. However, a sample of the claims studied suggests that these are mostly pedestrian injury claims.


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    • 1 Second Ago
  • 20 Comments
      Levine Levine
      • 3 Years Ago
      At any velocity, a heavier car will have more moment, mv, and kinetic energy, mvv/2 than a lighter one. That energy and moment must be transferred during a collusion. Most of the energy will be transferred to the masses and the remainder as heat and sound. If most of the energy is transferred to the lighter mass, as the author suggests, then the passengers inside the vehicles will receive majority of the energy, rather than the lighter vehicle. Under the same argument, a 2000 lbs reinforced concrete wall will receive more energy than a 4000 lb vehicle moving at any given speed. The result would be very illuminating. The key to passenger safety is energy absorption ability of the car frame, regardless of the weight of the other vehicle or wall. The 'crush zone' is designed to absorb energy by metal deformation and yielding of critical metal components.
        Timo
        • 3 Years Ago
        @Levine Levine
        If there is collision between 18-wheeler and SmartForTwo at highway speeds I don't think it needs an university degree to figure out which one does get hurt more. Problem with weight difference is that if both of them move at head-on collision, relative speed change in lighter vehicle is bigger because it doesn't stop the heavier vehicle. As a result it actually goes backwards in collision. For that 18-wheeler vs SmartForTwo at 50 mph for Smart that would be equal to nearly 100mph collision because that 18-wheeler doesn't slow much at all at that collision, and consequently 18-wheeler driver hardly even notice that there was an collision because his car didn't slow down much. So, even that there are crumble zones and passenger compartment stays intact heavier car passenger does suffer less acceleration in collision. It is a sad fact that heavier car is safer for passengers, because heavier is also more dangerous to anybody else, and people tend to think themselves before they think others. If everyone would be driving SmartForTwos then there would not be collisions between Hummer and Smart. Also heavier car is no safer when you collide it with other heavy car (except that there probably is more of that crumble zone to absorb energy).
      karlInSanDiego
      • 3 Years Ago
      "as the hybrids need 25 percent less personal injury protection than their conventional counterparts" What? Is Autoblog G. siting that 25 percent figure because manufacturers have calculated and published that statistic elsewhere, because the Press Release makes no such claim? Did some other group say it? The article says an average of 10% difference in weight between hybrid/convention. In the Civic it's less than 200 lbs. which is the difference between a passenger and none. Would you/they also claim driving with full tanks of gas 7.5 lb x 16gal makes us 17% safer due to the added mass? The disparity in number of hybrids vs. conventional renders their data inconclusive. This study is bunk. The part they could have gotten right but didn't is that the added mass on the hybrids plus mileage optimized tires equals greater stopping distance, and they'd have to back that up with testing, not supposition.
      2 Wheeled Menace
      • 3 Years Ago
      Summary: get a heavier car so that when you hit the other person, they die instead. That's the American way of thinking about safety.
      Spec
      • 3 Years Ago
      Well that will be a crap reason to advocate for EVs . . . buy an EV . . . they are heavy!
        Letstakeawalk
        • 3 Years Ago
        @Spec
        Always looking at the negative, aren't you? It's a *great* reason to advocate HEVs - they're safer. "The data shows that occupants are 27 percent less likely to be injured if they're in the hybrid version of the vehicle."
          Ele Truk
          • 3 Years Ago
          @Letstakeawalk
          It's the unspoken SUV mantra. Better in a crash for me, not you.
          EZEE
          • 3 Years Ago
          @Letstakeawalk
          :D (new slogan): 'Buy the EV - Better him than me!' (I make myself LOL sometimes...)
      Noz
      • 3 Years Ago
      A heavier car is safer only if the chassis and frame are up to the task of protecting the occupants inside. 2/3 of the car is behind the driver/passenger....that mass also has to go somewhere.
        EZEE
        • 3 Years Ago
        @Noz
        Look at me, backing you up.... Great point. As far as 'the American way of thinking safety' here is a video of a new Malibu versus a 1959 Chevy. Amazing results between the new, and the old iron. http://www.youtube.com/watch?v=joMK1WZjP7g&feature=youtube_gdata_player I like the windshield totally leaving the car. Who voted noz down? He simply stated a fact....
      Timo
      • 3 Years Ago
      Actual study is quite poorly made for pedestrian collisions (there is no link to that here). IIRC not all of those that have been counted as pedestrian collisions necessarily even included an pedestrian. It also doesn't take into account the environment where those collisions happen. If you want to make a lie sounding like a truth use statistics.
        EZEE
        • 3 Years Ago
        @Timo
        Great point - the government uses mathematics on their roll over ratings, opposed to statistics. The Corvette, for example, is rated excellent for roll over. Why not? Low, wide...they SHOULD NOT roll over... However.... People drive them like maniacs, so guess what? Corvettes roll over. Not necessarily the car's fault, but, there are going to be other, legitimate factors involved in a study of this type. Although the engine noise may be a factor, driving your electric in a busy city with pedestrians all over the place, all the time, opposed to long stretches of road with no people ACTUALLY MIGHT have a factor....
      John R
      • 3 Years Ago
      "Heavier cars are safer than lighter vehicles" "pedestrians might get involved in more accidents with hybrids because they can't hear the cars when they're in electric-only mode" "low rolling resistance tires often inhibit stopping ability" "hybrids are also slower and less maneuverable than their non-hybrid counterparts" Wow, much FUD from ABG today?? I don't know where to start...
        Letstakeawalk
        • 3 Years Ago
        @John R
        It's not FUD if it's true. Every automobile has strengths and weaknesses.
      Marco Polo
      • 3 Years Ago
      While in general I like anything positive regarding Hybrid or EV's, I must agree with Timo that the analysis of the dynamics involved in motor vehicle collisions, are very complex and often interpreted to support a pre-conceived theory.
      • 3 Years Ago
      The report is missing a crucial piece of information: the speed of the hybrids involved in pedestrian accidents. If the 20% higher number of such accidents occurred at 20+ mph, Congress is wasting everyone's time and money enacting a useless law, since their mandated "noise-makers" only engage below 20 mph.
        EZEE
        • 3 Years Ago
        I want my engine noise maker to play 'tequila'
        JakeY
        • 3 Years Ago
        What's really critically missing is factoring in the driving patterns of hybrid owners vs the average car owner. I'm willing to bet hybrid owners drive significantly more in places that have pedestrians (aka urban/city) than other cars, since that is where hybrids save the most gas compared to conventional vehicles. In other words, there may be a very strong correlation between hybrids and pedestrian accidents simply because they are driven in more places that have contact with them. That doesn't mean it is because of the lack of "noise-makers".
          JakeY
          • 3 Years Ago
          @JakeY
          @niky Speed doesn't tell the whole story. Even if the accident speed was mostly under 20mph and similar in both the average and hybrid case, the correlation I mentioned will still skew the results. They did look at registered vehicles per square mile, but that doesn't tell the whole story on driving patterns (how many miles/how much time do the cars drive in a situation where there is even a risk of pedestrian impact). Another thing is why is no one looking at other quiet cars (luxury cars mainly) and adding noise makers to them too? Why only focus on those with electric drivetrains? If you look at the conclusion, the pedestrian collision data in this study is shaky anyways: "Moore points out that HLDI can't definitively tell from the claims data that a crash involved a pedestrian. Likewise, some pedestrian crashes may have been unintentionally excluded. For example, a crash in which a person was struck and injured and the vehicle also was damaged would have been omitted because a collision claim would have been filed for the damaged vehicle. However, a sample of the claims studied suggests that these are mostly pedestrian injury claims."
          niky
          • 3 Years Ago
          @JakeY
          This was the first thing I thought of when I read the study... driving patterns. They adjusted for traffic densities and gender/age, but how do you adjust for personality profiles and car performance? The person buying a Civic hybrid or even an Accord hybrid, despite its sporting pretensions, will have different driving patterns and a different personality from a person who is buying a gasoline powered vehicle. Thus... at what speeds do said vehicular accidents happen? Are the gasoline variant crashes happening at the same speeds as the hybrid accidents? Do gasoline drivers drive in suburban environments at low speeds as often as hybrid drivers (pedestrian claims)?
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