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IIHS Says Its Crash Test Study Suggests Small Cars Can’t Protect People in Front-to-Front Crashes as Well as Bigger, Heavier Models

Three 40 mph car-to-car front-to-front crash tests, each involving a microcar or minicar into a midsize model from the same manufacturer, indicate that extra vehicle size and weight enhance occupant protection in such collisions, according to the Insurance Institute for Highway Safety, which ran the testing. A summary of the study is published in the 14 April IIHS Status Report.

The choice of midsize cars reveals how much influence some extra size and weight can have on crash outcomes, the Institute said. The Institute chose pairs of 2009 models from Daimler, Honda, and Toyota because these automakers have micro and mini models that earn good frontal crashworthiness ratings, based on the Institute’s offset test into a deformable barrier.

Researchers rated performance in the 40 mph car-to-car tests, like the front-into-barrier tests, based on measured intrusion into the occupant compartment, forces recorded on the driver dummy, and movement of the dummy during the impact.

IIHS video. Click to play.

The Honda Fit, Smart Fortwo, and Toyota Yaris are good performers in the Institute’s frontal offset barrier test, but all three are poor performers in the frontal collisions with midsize cars. Although the physics of frontal car crashes usually are described in terms of what happens to the vehicles, injuries depend on the forces that act on the occupants, and these forces are affected by two key physical factors, the Institute said.

One is the weight of a crashing vehicle, which determines how much its velocity will change during impact. The greater the change, the greater the forces on the people inside and the higher the injury risk. The second factor is vehicle size, specifically the distance from the front of a vehicle to its occupant compartment. The longer this is, the lower the forces on the occupants.

Size and weight affect injury likelihood in all kinds of crashes. 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 during the impact. This means there will be less force on the occupants of the heavier vehicle and more on the people in the lighter vehicle. Greater force means greater risk, so the likelihood of injury goes up in the smaller, lighter vehicle.

Driver deaths per million 1-3-year-old cars registered, 2007. Source: IIHS. Click to enlarge.

Crash statistics confirm this, the Institute said, noting that driver deaths per million 1-3-year-old minicars in multiple-vehicle crashes during 2007 was almost twice as high as the rate in very large cars. (The rate for small cars—larger than minicars—was even higher than the driver death rates for minis, while the driver death rate for large cars was higher than that for midsize cars.)

The death rate per million 1-3-year-old minis in single-vehicle crashes during 2007 was 35 compared with 11 per million for very large cars. Even in midsize cars, the death rate in single-vehicle crashes was 17% lower than in minicars. The lower death rate is because many objects that vehicles hit aren’t solid, and vehicles that are big and heavy have a better chance of moving or deforming the objects they strike. This dissipates some of the energy of the impact.

Honda Accord versus Fit: The structure of the Accord held up well in the crash test into the Fit, and all except one measure of injury likelihood recorded on the driver dummy’s head, neck, chest, and both legs were good. In contrast, a number of injury measures on the dummy in the Fit were less than good. Forces on the left lower leg and right upper leg were in the marginal range, while the measure on the right tibia was poor. These indicate a high risk of leg injury in a real-world crash of similar severity. In addition, the dummy’s head struck the steering wheel through the airbag. Intrusion into the Fit’s occupant compartment was extensive. Overall, this minicar’s rating is poor in the front-to-front crash, despite its good crashworthiness rating based on the Institute’s frontal offset test into a deformable barrier. The Accord earns good ratings for performance in both tests.

Mercedes C class versus Smart Fortwo: After striking the front of the C class, the Smart went airborne and turned around 450 degrees. This contributed to excessive movement of the dummy during rebound—a dramatic indication of the Smart’s poor performance but not the only one. There was extensive intrusion into the space around the dummy from head to feet. The instrument panel moved up and toward the dummy. The steering wheel was displaced upward. Multiple measures of injury likelihood, including those on the dummy’s head, were poor, as were measures on both legs.

In contrast, the C class held up well, with little to no intrusion into the occupant compartment. Nearly all measures of injury likelihood were in the good range.

Toyota Camry versus Yaris: There was far more intrusion into the occupant compartment of the Yaris than the Camry. The minicar’s door was largely torn away. The driver seats in both cars tipped forward, but only in the Yaris did the steering wheel move excessively. Similar contrasts characterize the measures of injury likelihood recorded on the dummies. The heads of both struck the cars’ steering wheels through the airbags, but only the head injury measure on the dummy in the Yaris rated poor. There was extensive force on the neck and right leg plus a deep gash at the right knee of the dummy in the minicar. Like the Smart and Fit, the Yaris earns an overall rating of poor in the car-to-car test. The Camry is acceptable.

There are good reasons people buy minicars. They’re more affordable, and they use less gas. But the safety trade-offs are clear from our new tests. Equally clear are the implications when it comes to fuel economy. If automakers downsize cars so their fleets use less fuel, occupant safety will be compromised. However, there are ways to serve fuel economy and safety at the same time.

—IIHS President Adrian Lund

Lund said that the structure of the new fuel economy standards for MY 2011—which use a size-based system rather than a fleet average and which will mandate lower fuel consumption as cars get smaller and lighter—will remove the incentive for automakers to downsize their lightest vehicles to comply with CAFE. It also could mean, he noted, that technology currently used to enhance horsepower would go instead to reduce gas consumption—a direct safety benefit because less powerful cars have lower crash rates.

Another way to conserve fuel, and serve safety at the same time, the Institute said, is to set lower speed limits. Going slower uses less fuel to cover the same distance. The national maximum 55 mph speed limit, enacted in 1974, saved thousands of barrels of fuel per day. It also saved thousands of lives. Highway deaths declined about 20% the first year, from 55,511 in 1973 to 46,402 in 1974. The National Research Council estimated that most of the reduction was due to the lower speed limit, and the rest was because of reduced travel. By 1983 the national maximum 55 mph limit still was saving 2,000 to 4,000 lives annually.

Fifty-five was adopted to save fuel, but it turned out to be one of the most dramatic safety successes in motor vehicle history. The political will to reinstate it probably is lacking, but if policymakers want a win-win approach, lowering the speed limit is it. It saves fuel and lives at the same time.

—Adrian Lund

The president of smart USA, Dave Schembri, issued a statement related to the Insurance Institute’s test:

This non-standard crash test performed by the Insurance Institute for Highway Safety (IIHS) simulates a crash situation that is rare and extreme. The test used an extremely high crash severity which is unlikely to occur in real world crashes. In fact, less than 1% of all crashes fall within these parameters.

The test conducted by the IIHS was not consistent with how federal regulators evaluate vehicles in crash tests. The National Highway Traffic Safety Administration (NHTSA) requires that cars and trucks of all sizes meet stringent safety requirements.

The smart fortwo meets or exceeds all US government crash test standards, including a 5-star side crash rating, and previously earned the highest scores for front and side crash worthiness from the IIHS in its standard test. The smart fortwo is equipped with advanced crash avoidance and crash protection safety systems, including electronic stability program (esp), and a reinforced steel safety cage called a tridion safety cell, which is standard equipment on all models.

For the past decade, smart has a proven track record of safety with approximately one million cars on the road in 37 countries. People drive small cars for many reasons, not just fuel economy as the IIHS states. People choose small vehicles because they are generally more environmentally friendly, a great value, they provide for greater driving and parking options in congested urban areas and many consumers tell us they are simply more fun to drive.



Will S

less than 1% of all crashes fall within these [IIHS] parameters.

So we have virtually useless tests that the IIHS wants us to use as a basis for fuel economy standards. And they want to separate SUV/truck fuel economy standards from car standards. While only short-sighted persons are buying light trucks these days, the only way to encourage reduced oil consumption at point-of-sale is have a single corporate target for automakers to meet.

IIHS recommendations? Buy a 25mpg Camry instead of a 32 mpg Yaris; in other words, forego the 30% fuel savings of the Yaris, and sacrifice greater oil independence so that more people can drive larger vehicles.

They also recommend 55mph highway limits, which I'm already practicing anyway, with a 25% savings in fuel expenses.


So how many is 1%? If we avg 500 car crashes per day does that translate to 35 deaths per week.

It's OK to be dead, just as long as your footprint is remotely smaller.

How about we make the Camry get 32mpg's and send the deathtrap, I mean microcar, to the recycle bin.

\\\Microcars have their place in high density urban settings, just don't do it in the suburbs!


No what they are saying is the obvious that a micro car isnt as safe as a mid sized car in a high speed crash.. and golly ge willikers why would the insurance institute for HIGHWAY HIGHWAY HIGHWAY DID I MENTION H I G H W A Y SAFETY might want people to remember that little fact?

Just because its got a 5 star rating doesnt mean its as safe as a different sized car getting even a 4 star rating or hell even a 2 star. Specialy in real world crashes.

In this case they are mostly looking at the real world results of the crashes.. as in insurance costs for lost limbs brain cells vital and semi vital organs and of course lives. A car is cheap a life is not.


It's not weight that determines crash protection, but energy-absorbtion capacity in the design. It is good to be open about how well a car's design performs, but we should not mislead the public by telling them that they have to buy heavy, gas-guzzling cars to be safe. Lightweight materials and good design can make a car efficient and safe.


No it is weight in a car to car crash the small car takes a much higher impact. Also even in a car vs bloody big object crash a heavy car's mass keeps it moving a bit longer reducing g forces.

Dave R

I don't get it - instead of recommending bigger and heavier cars for everyone, why not recommend lighter cars which would make the roads safer for everyone else? Why encourage a vehicular "cold-war" where everyone feels they must purchase the biggest and heavier vehicle on the road, even when those vehicles tend to have the highest death rates - to themselves and to others?

This way you get the best of both worlds by reducing the number of big, heavy vehicles which do a lot of damage to other vehicles and the obvious efficiency benefits of having to move less mass around.

It seems to me that heavier vehicles should be penalized by horsepower limits to discourage people from buying them unless they are needed. Or another way - make fuel efficiency target disproportionally more difficult to meet for heavier vehicles.

Will S

instead of recommending bigger and heavier cars for everyone, why not recommend lighter cars which would make the roads safer for everyone else? Why encourage a vehicular "cold-war" where everyone feels they must purchase the biggest and heavier vehicle on the road, even when those vehicles tend to have the highest death rates - to themselves and to others?

Precisely. And then we can reduce our dependence on foreign oil, meaning fewer wars and fewer lives lost in said wars. It's sad and ironic when I hear people say, "I've got to get an SUV to protect my kids from those other jerks who feel they need to drive SUVs."


A mid sized suv is not a bad idea for a long trip family car and it can hold its own vs a nitwitmobile. A microcar cant hold its own vs a mime on a unicycle.


People buy small cars for lots of reasons, only one of which is that they get better gas mileage. One is that they are cheap. If they were made safer, they might not be so cheap and therefore may not sell.

These studies lump together categories of cars based on size, not why people buy them. Some big cars are unsafe and some small cars are safe, but they get lost in the averages.


The biggest impact [pardon the pun] on the safety of a car isn't it's weight or size: It's the driver.

I'm sure you've seen them; the idiots that drive with a cellphone in their ear and/or a cup of java in their hand. I've gone down the highway and looked over at passing cars to see drivers not watching the road because they were texting on their blackberry and just last week I saw a woman in the oncoming lane driving while nursing her baby.

What's the worst I've seen? - I remember seeing one guy (some years ago) driving around while reading from a clipboard that was wedged between his steeringwheel and the windshield. The thing that scared me was that it was a driving school car and he was an instructor!

And then there's signaling a turn, ~60% of the time people don't.


The Saturn SC and SL models were 600 pounds lighter than a Cobalt using the space frame and light body panels and they had good crash ratings.


Like Dave R and Will S, I think this is not that complex.

Big cars kill people in little cars in a bad crash and so it is better to have fewer big cars.

Big cars usually have more crumple distance but two Escorts hitting head on is not much worse than two Buicks.

If I hit a truck head on in my Civic, I go from 50 mph to minus 30 mph in an "instant" while the truck goes from 50 mph to 30 mph.
He's upset.
I'm dead.

If I had the same crumple space as the truck driver I would still not likely survive; I would still go from 50 mph to minus 30 mph, it would just take a longer "instant".

If I hit another Civic we both might survive.


The plumber that comes to your house to fix the @$^%*& drives a 1 ton with side compartments. That will not change until after your great grandchildren are long dead and buried. If you drive a micro-car anywhere but downtown you may never meet those great grandchildren. Get yourself a midsized car or take your chances, your choice. My midsized get 45mpg, do not bring you micro to the suburbs, it's suicide.



Please be reasonable, no that's not suicide , in Europe people drive mostly small, the car density is higher than in US and prople drive faster and more agressively the number of fatalities on the road is lower than in US. I commute biking half of the time on a recubment that on which I am reclined 23 de at one foot from the ground, I am feel perfectly safe even with no shell around me, I am careful and though I ride fast I anticipate the danger so I am still alive. Following your reasoning we should always drive bigger than the neighbour to be sure to have the advantage in front crasj collision, well that is going nowhere. The type of accident they tested here is very rare, people don't kill themselve in from collision with another car, people kill themselves in roll-over and here SUV and Pick Up are at their disadvantage.

Solution, increase drastically the cost of insurance for SUV and Pick for the damage they can cause to smaller car, problem solved. No more of these ugly SUVs and Pick Up and the world will just be a better place to live.


Treehuger, dude, I am one of the few truly reasonable moderates that post here. Usually I have you on one side and Stan on the other, you are both loony tunes.

raising rates on PU's is a tax on the middle class blue collar, you remember, the people that actually work for a living.

We can put robots on other planets that rome around for three years but my PU can only get 15mpg.

The car companies have failed us!


At last, a more honest test.

I believe that my invention solves the problem of
making cars lighter and safer.

raising rates on PU's is a tax on the middle class blue collar, you remember, the people that actually work for a living.
And why does a blue-collar guy need a pickup truck to commute to work?  What do European blue collar workers commute in?  Anyone?  Anyone?  Bueller?

This is another of the bogus arguments against fixing our petroleum-dependency problem.  Gas taxes "hurt the poor".  Penalizing dangerous vehicles "is a tax on people who work for a living".  Why not build vehicles that are light AND have lots of crush space?  Uhhhh......

I would not be surprised if these bogus arguments are part of an astroturf campaign financed by Saudi Arabia.


Adrian Lund doesn't get it. Some posters don't get it.

It is not the absolute size of a car that determines safety, it is the relative size to the other 'objects' involved in a crash. So promoting bigger cars for more safety as Adrian Lund seems to be doing will only be a temporary advantage of those driving that bigger cars. They will keep that advantage until even bigger and heavier SUV's come along. Promoted by Adrian Lund of course: "Our research shows that a gargantuan SUV protects its occupants better in a collision with a huge SUV"


You have to take the IIHS for what they are. They are only concerned with safety as it relates to reduced insurance claims. One of these manufactures wil redesign their mini to allow the vehicle to absorb more impact than the occupant and the IIHS will just criticize them for having costly repairs after an accident. They are definitely not concerned about fuel economy.

Insurance Institue for Highway Safety is a misnomer but I will give them credit for clearly stating what they are all about on their webpage.

"The Insurance Institute for Highway Safety is an independent, nonprofit, scientific, and educational organization dedicated to reducing the losses — deaths, injuries, and property damage — from crashes on the nation's highways.

The Highway Loss Data Institute shares and supports this mission through scientific studies of insurance data representing the human and economic losses resulting from the ownership and operation of different types of vehicles and by publishing insurance loss results by vehicle make and model.

Both organizations are wholly supported by auto insurers."



I agree with you. This type of argument could lead to a country wide race for bigger and bigger cars. Even 4-tonnes vehicles qould not do so well against 18+ wheelers, etc etc. Of course, a country with 250 + million Hummer size vehicles would import and use twice as much oil and pollution 3 to 4 times as much etc.

If monster owners want to crush smaller vehicles, they could have reserved roads to blow up the steam.

Most of us do not need a huge vehicle to go from A to Z. A 50 mpg Prius III (or equivalent) would do in most cases.


It looks like a very expensive advertisement for the new fusion hybrid.

Also can be used for as a primer for lower speed limits. Although the data is totally irrelevant as speeds are much higher than tested.

SHOULD BE an advertisement for driver training. Despite the increase in automotive safety, the safest person on the road is the one that does not hit anything....but that makes sence.


Nothing says new car like seeing a family in your exact model of car torn to bits in a crash with just a normal car. Everyone expects to die in an 18 wheeler accident they dont expect to die in a yugo accident.

To make matters worse of course bad drivers tend to drive bigger cars because of course they need to to stay alive;/

Perhaps if realy bad drivers and drunk/high drivers had to drive smaller and smaller cars we wouldnt see so many mangled families on the road.


This goes to show that more work needs to be done with automobiles to make them safer. Most all new cars now have great safety ratings, and the IIHS knows that the bar must now be raised.

This is obvious when 4 out of the 6 tested cars had dummies with head injury levels of force. Yes, the light cars crashed very poorly. But the heavy Camry did not manage the crash well; and there was also a strike against both the Accord and the C Class. Light cars need the most work to make them more safe. Heavy cars need less work, but still need improvements.


One may be more likely to get into an accident in an SUV in the first place. They do not handle as well nor stop as quickly in a panic situation. Couple that with a cell phone call while driving and you might survive hitting that tree, but may be more likely to do so....safer?


I think we need a little perspective here, this was a 40 mph each way head on collision. Quite severe. 80 mph into an object. Yet all drivers would have survived, injured but survivable.

How safe do we have to be? Is it necessary to survive all accidents? At what point is the weight required and/or cost of building a car that will protect you from an 100+ impact too much?

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