Go Greener Tips

pemRocky Mountain Institute (RMI) has been advocating the entry of fuel-efficient cars
into the market for years, for security and economic reasons as well as
environmental. On May 19, 2009, President Obama announced a historic agreement
to help America break its addiction to oil. The centerpiece of that
announcement was a a href=http://green.yahoo.com/blog/daily_green_news/68/obama-accelerates-car-efficiency-and-emission-standards.htmlnew 35.5-mpg CAFE standard for 2016/a. This is a pivotal time
to envision innovative transportation solutions as we work to rebuild the
domestic auto industry./em/pbr /div class=image style=float: right; padding-left: 8pxpimg alt=Toyota height=200 src=http://a323.yahoofs.com/ymg/amorylovins/amorylovins-986794886-1244762577.jpg?ymRXyZBD6E7VUSec width=359 /br /emThe Toyota 1/X: A prototype for a highly efficient,br /lightweight hybrid vehicle. (Photo: Toyota)/embr /br //p/divpOne of the barriers to American adoption of fuel-efficient vehicles is the
common-yet-misleading line of logic that fuel efficiency equates to smaller,
less safe cars. /ppThis misperception is often fed by the media headlines, including an April 14, 2009, emNew York Times/em story, Study Says Small-Car Buyers Sacrifice Safety for Economy and a May 22, 2009, Wall Street Journal piece, titled Light Cars Are Dangerous Cars./ppYet the relationship is not that simple. What is left out of this quick-and-easy
debate is the role of engineering design. Sure, based purely upon a typical
vehicle’s design, geometry, and occupant position, it’s true that larger — but
not necessarily emheavier/em — vehicles can offer considerable safety advantages to passengers within./ppRocky Mountain Institute’s survey of
existing studies indicates that lightweight vehicles can be as safe, or even
safer than, the cars on the road today through the use of stronger, lighter
materials when engineering design is focused on crash safety. Additionally,
lightweight cars have great advantages when it comes to fuel-efficiency. /ppDesigning for passive safety on par
with current NHTSA five-star ratings demands not only using lightweight
materials, but also new vehicle geometries and components that can act as
energy-absorbing crumple zones. Indeed, a lighter vehicle can achieve the
performance of a conventionally designed vehicle, but because it can do so with
a smaller engine, there is more room in the engine compartment for crush space and,
ultimately, a better crumple zone design. /ppThere is another aspect of safety
to consider: the safety of the people emoutside/em
the car. A lightweight vehicle will be less emaggressive/em
(less likely to injure the occupants of another vehicle, bicyclists, or
pedestrians during a collision). For objects moving at a given speed, less mass
reduces the energy that an object brings into a collision. Thus, a lightweight
fleet (traveling at the same speeds) can statistically reduce the overall
number of traffic deaths compared to a conventional (heavy) fleet./ppRMI continues to encourage manufacturers to
design and build efficient, lightweight cars — and to support legislation that helps focus
our automakers on priorities that benefit us as a society.a href=#ftn1[1]/a We
hate to see the benefit that comes from fuel efficiency thwarted by
misconceptions about safety trade-offs. Both fuel efficiency and safety can be
achieved, and both are good for the health of the country in more ways than just
safety on the road. /ppRMI continues to do more research
on this topic and is seeking partners to work with. Preliminary results of a
recent RMI study are expected to be released in July. For additional information, please visit a href=http://www.rmi.org/www.rmi.org/a. /pbr /pemThe
authors are all employees of Rocky Mountain Institute, where Mike Simpson is a
transportation analyst, Kristine Chan-Lizardo is Interim Director of the
Mobility and Vehicle Efficiency Team (MOVE), Cory Lowe is a public relations
manager, and Cameron M. Burns is Senior Editor./em/pbr clear=all /hr align=left size=1 width=33% /pa name=ftn1 title=ftn1/a[1] As part of
our research on vehicle lightweighting, RMI reviewed all the existing studies
and commentary about the relationship between size, safety, and weight,
including reports published by the National Academy of Sciences and the
National Highway Traffic and Safety Administration, and the Insurance Institute
for Highway Safety (IIHS). Many reports link size and weight as being
responsible for safety reductions, while the most recent studies separate the
two, and find size alone to blame. /ppIn a
January 2007 article, IIHS stated a way to improve fuel economy and maintain
vehicle crashworthiness is to use lighter materials that reduce vehicle weight
but not size. IIHS also noted … some weight reduction, especially among very
heavy vehicles, could improve total safety by lowering the risk to other people
on the road./ppThe fact is that today, there are not many examples of
vehicles that have been designed to be both lightweight and large. This is changing as
overseas automakers, and hopefully our domestic automakers as well, explore
designs and materials that areem both/em fuel-efficient and safe. /p

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