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Study: No Trade-Off Between Higher Fuel Economy and Vehicle Safety

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Sample safety risks of existing vehicles with high (green) and low (red) fuel economy. Click to enlarge.

A new study concludes that there is no trade-off required between higher fuel economy and vehicle safety.

The study, informed by an October 2006 experts workshop titled Simultaneously Improving Vehicle Safety and Fuel Economy through Improvements in Vehicle Design and Materials, concludes that manufacturers can use advanced materials to increase both fuel economy and safety without reducing a vehicle’s functionality. It also finds that reducing the weight and height of the heaviest SUVs and pickup trucks will simultaneously increase both their fuel economy and overall safety.

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Technology options for increasing fuel economy and/or safety. Click to enlarge.

The authors conclude that existing technology options can improve light-duty vehicle fuel economy by up to 50% over the next 10 years without reducing the weight or size of vehicles. Any extra cost associated with the auto-manufacturing changes would be more than offset by savings generated by more fuel-efficient vehicles.

A common argument against mandating significant increases in fuel economy is that such efficiency requirements would greatly decrease the safety of vehicles, thereby leading to increases in traffic fatalities.

The potential to improve the fuel economy of light-duty vehicles while also improving traffic safety is debated because of the claim that lighter vehicles are, and will forever remain, more dangerous for their occupants. The critical issue is whether these historical tendencies are intrinsic, or whether they continue to change over time with new designs, testing, and sound regulations. The reality is that these relationships are not intrinsic to motor vehicles. Rather, the linkages among fuel economy, vehicle size, weight, and safety are manageable and are more a function of smart vehicle design than any other single factor.

Sipping Fuel and Saving Lives: Increasing Fuel Economy without Sacrificing Safety

The authors of the study, Sipping Fuel and Saving Lives: Increasing Fuel Economy without Sacrificing Safety, are Deborah Gordon, a transportation policy consultant; David L. Greene, a fuel-economy policy expert; Marc H. Ross, emeritus professor of physics at the University of Michigan; and Tom P. Wenzel, of the Lawrence Berkeley National Laboratory.

The study’s authors reviewed a decade’s worth of recent research in the field and concluded:

  • Most technologies to increase fuel economy do not affect safety; most technologies to increase safety do not affect fuel economy.

    The inherent relationship between vehicle safety and fuel economy has long been the subject of discussion. The many technologies available to improve vehicle fuel economy (particularly those that do not involve weight reduction) have no impact on vehicle safety. Those approaches that strategically reduce vehicle weight (using new lightweight materials to reduce weight while holding vehicle size constant and reducing the weight of the heaviest trucks and SUVs to make them less aggressive) also improve fuel economy while maintaining, and perhaps even improving, vehicle safety.

  • Reducing car mass while improving vehicle structure, using advanced materials and designs, can simultaneously increase fuel economy and safety.

  • Reducing the weight and improving the structure of truck-based SUVs and pickups can increase their fuel economy and improve the safety of all vehicles on the road.

The study recommends that policymakers:

  • Set fuel economy and safety performance goals at cost-effective levels, and allow adequate time for phase-in of vehicle redesigns.

  • Develop short-term goals that use existing technological potential and long-term goals to spur continued innovation.

  • Apply the same fuel economy and safety standards consistently to all vehicle types (cars, SUVs, and pickups).

  • Encourage driver behavior that improves fuel economy or safety—e.g. seat belt use or reduced driving speeds.

The report was presented by the International Council on Clean Transportation (ICCT). The William and Flora Hewlett Foundation convened the experts meeting that led to the report.

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Comments

DS

"This is intrinsically counter intuitive to any Engineer."

I'm an engineer, and this is old news. The differnce between a safe car and an unsafe is that the safe car was designed to be that way.

It's intuitive that the Sun moves around the earth.
This reminds me of what my first boss said when I bitched about a project. He said "if it were easy (intuitive) I'd have the secretaries do it."

Lad

JC:
One safety standard badly needed is a bumper height standard; there are far too many hiked up, trucks with huge tire driving the roads.

A law that is needed is to have trucks with extended tow hitches and side mirrors remove them except when they are towing. They are in effect weapons to destroy other people's bumpers and the side mirrors have taken lives. I'm sure the insurance companies love 'em.

Neil

I've often wondered why there is no set hight for bumpers. It's such a no-brainer as far as safety is concerned.

R

Sadly, the average US educated engineer couldn't design their way out of a box and this is coming from an US educated engineer. A lot of the new safety features these days don't require significantly more hardware, just more intelligence from processing and sensing or better design. It's like the days of trying to build an earthquake resistant building by making it stiffer, it's thinking of the problem from a completely bone-headed perspective. Just like how building more fuel-efficient cars will not cost billions of dollars as claimed by the car manufacturers.

Booker

GreenCarGuy,

Knock yourself out. If it helps, I will now refer to you as being a douche as well, much more so than James who was a condescending jerk.

GCG: "Mike! Mike! Booker is being mean to me! Booker keeps poking me!"

Mike: "If you don't stop I'll turn this car..er..SUV around right now!"

:D

wintermane

The reason there is no sry height specialy for suv and truck bumpers is ground clearance. If they set a compatable universal bumper height small cars would have bumpers a foot above the hood or high clearance trucks would not have any clearance....

richard

you guys act as if more than 3% of the economy shares your goals of high effieciency cars. What we need is Hybrid SUV's and Pickups so these American familys can still have safe choices and will save more gas than switching from a corolla to a prius.

Tom

The argument about weight ... although correct ... is misleading. Sneakers could be considered a form of transportation but are extremely dangerous in head on collisions with even the lightest cars. SUV's in head on collisions with rock filled dump trucks have problems also.
A very important part of safety is not getting into the collision in the first place. ABS brakes, anti-skid controls, and tires with proper tread might do better in reducing the overall number of fatal accidents than wrapping the car in a rigid steel frame. Does anyone have numbers for those features? I bet the car insurance people do.

darwin

Another problem with bumper height regulation is that the height of the front bumper drops about 6 inches when you slam on the brake. Conversely, the back bumber comes up about 6 inches. So you're talking about a range of greater than a foot at which the impact point could occur. It's not feasable to have a back bumper on a truck that while breaking, stays low enough to take the hit from a small car hitting the back. Conversely, it's not feasable to have a sportscar with a front bumper high enough to hit the back bumper of a truck that is slamming on the brakes.

William

That is why you used to see bumperstickers on lifted trucks
that read " smile as you go under ". It was those off-roaders
that would dare you to rear end them.

Patrick

Bumper height laws very by state and is often stated in the "driver's manual" or similar documents. In California, they have issued citations for lifted trucks and lowered econo-boxes due to failing to meet the minimum and maximum bumper heights.

Tom,

While crash avoidance is more important than mitigation the sad fact is that the overwhelming majority of accidents are due to driver error in the first place. If someone rear ends another vehicle because they were not paying attention to the road and traffic, no amount of ABS and ESC will help them unless the car were to automatically engage the brakes for you.

Ben

"will help them unless the car were to automatically engage the brakes for you."

Behold the future: cars that drive for you, who knows how many lives "smart" cars will save despite there driver's inattentiveness or drunkens, no matter the size of the car will it not be safer if it has gut reactions?

Oh and it seems my previous comments angered some people, I'm sorry I did not expect those kind of people here.

tc

1) It's the driver, Stupid. I mean, it's stupid drivers.

2) Industry is ALWAYS opposed to regulation; even mandatory seat belts. The only reason they even participate in this one is b/c they LOVE the strawman of the either/or proposition between fuel economy and safety.

3) Design matters . . . crumple zones, side impact beams, vehicle shape, re-inforced passenger zones, material choice, etc.

4) Manufacturers (and consumers) always have choices: 18 inch wheels/V8 versus 17 inch wheels/V6 versus 16 inch wheels/inline four.

The study just highlights what every knowledgeable person already knows. In the United States, vehicle weight is largely an independent predictor of fuel economy, while it is NOT an independent predictor of safety. The difference in other markets is the availability of diesels and relatively small displacement gasoline engines. Diversity in engine availability has no impact on safety but a profound impact on fuel economy . . . and NOx.

This is Green Car Congress so the optimum would be to minimize vehicle weight (for fuel economy) while maximizing safety (through design). But it won't happen if we rely on automakers.

It's America so naturally the other issue is performance (or bragging rights). It would be nice if people didn't have this ridiculous desire to own a vehicle that can tow 4-5 tons or hit 60 under 5 secs. Unfortunately, Japan Inc has decided to COPY the domestics. That's the reason why the ONLY way we will make progress is for the government to mandate higher fuel economy standards AND tax fuel to keep the price high.

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