COMMENT: Lighter vehicles are not unsafe

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Fuel Economy > Fuel Economy

Occupant protection gets better and better

By Rob Chapman
Automotive News / October 17, 2005

Weighing inMany recent developments promise to reduce vehicle weight and/or protect occupants better. Here are a few.
  • According to SAE's Automotive Engineering International (September 2005), the Delphi Driver Protection Module incorporates energy-absorbing technology and provides head-to-toe protection.
  • According to Automotive News (Sept. 19), Siemens VDO's new brake-by-wire concept reduces the weight of a vehicle's braking system by removing the hydraulics.
  • Also according to Automotive News (March 31): "Automakers can reduce the weight of vehicles without making them less safe, the Aluminum Association says. … Size matters more than weight, the group says."
  • In a May 2000 press release, the Ultralight Steel Auto Body Closure consortium reported on a complete frameless door made of a high- and ultrahigh-strength steel tubular frame and a stamped steel outer panel. It weighed 22% less than the framed best-in-class benchmark and was 42% lighter than the average frameless door. Safety and structural performance were not compromised, and there was no cost penalty.
  • For some time, critics of government regulation have contended that it is dangerous for the automobile industry to produce lighter vehicles. Lighter vehicles will be unsafe, they say.

    An impetus for that viewpoint was a 2002 National Research Council report, "Fuel Economy and Safety." It claimed that historical data showed that heavier vehicles were safer than lighter ones.

    The most visible critic has been The Wall Street Journal editorial page. A Sept. 14 editorial, "No blood for oil," implied that 2,000 more people would be killed every year if increased corporate average fuel economy standards were applied (by 2010). That would force the auto manufacturers to lighten their cars and trucks, making them less safe.

    This dogmatic line irritated me, so I sent a letter to the editor contesting that point.

    Not mutually exclusive

    Ralph Nader, not historically a defender of the auto industry, also responded. He concluded that "auto engineers can deliver" lower-weight and safer vehicles.

    The point I made in my letter was that the consequences predicted in the editorial wrongfully assumed that automotive crash-protection technology would remain unchanged indefinitely, as would structural and materials know-how. Many developments today promise greatly improved occupant protection and decreased vehicle weight.

    A striking example was given to me by Robert Hall, professor emeritus of operations management at Indiana University and one of my fellow Automotive News PACE Awards judges.

    Look at race cars

    "In the last 40 years," Hall said, "auto racing speeds have increased, yet deaths have decreased significantly while the weights of the vehicles have gone down progressively. Why? Crushable fronts that absorb impact, 'tubs' that shelter drivers after the entire car has disintegrated, a relocation of the front axle and, yes, crash bags. In this case, lighter is markedly safer."

    As a member of the Society of Automotive Engineers, I have attended SAE's annual World Congress for more than 10 years. Every year, hundreds of technical papers are presented. I have never heard of a presentation on vehicle weight increase as a means of occupant protection.

    The technical sessions focus on new techniques to improve safety and reduce fuel consumption. Conversely, presentations have cited weight savings as a benefit, for cost reduction and fuel efficiency.

    Am I agreeing with Nader, of all people? Well, yeah. And, essentially, so does David Greene, a research fellow at Oak Ridge National Laboratory. With his colleague, Maryann Keller, he wrote a 15-page "Dissent on Safety Issues" to the National Research Council's 2002 report. Greene and Keller wrote, "There is no fundamental scientific reason why decreasing the mass of all vehicles must result in more injuries and fatalities."

    Loopy

    Bill Sharfman, the director of judging for the PACE Awards for innovation, called the Journal editorial "one of the loopiest attempts at converting ignorance into knowledge I have encountered this year."

    He went on: "Take a look, for instance, at the aluminum space frame used by Audi, or Jaguar's monocoque aluminum chassis. … Jaguar saves 600 pounds on that chassis. … It's rigid, strong and light."

    Even the Journal's newsgathering people undercut the editorial. A Sept. 26 front-page article was headlined: "Crash course: How U.S. shifted gears to find small cars can be safe, too." The first part of the subtitle says it all: "Studies discover size, quality are as important as weight; drafting rules for SUVs."

    But what is this all about? A clue might be found in a Sept. 12 letter to the editor of Automotive News. Jacqueline Glassman, the deputy administrator of the National Highway Traffic Safety Administration, in discussing a proposal for a new way of counting CAFE, wrote, "The standards also would increase safety by no longer forcing automakers to build dangerously light vehicles in an effort to game the CAFE standards."

    If the automakers could be forced to create unsafe light vehicles, would they be stupid enough to do it? Would their defense in a class-action suit be that "CAFE made me do it"?

    There has been a recurring contention that heavier vehicles are safer. But even the experts disagree on that point. The more important question is whether lighter-weight vehicles can be made to be as safe as heavier ones. The evidence suggests they can be.