JEEP LIBERTY or Wrangler owners probably don't know it, but their Toledo-made vehicles' gas mileage is directly linked to Chrysler's PT Cruiser.
Because the Cruiser gets strong gas mileage, the sport-utility vehicles with poorer fuel economy can squeak by the government's mileage standards for a fleet.
But that is about to change.
The U.S. Department of Transportation issued rules six weeks ago that, after 2010, require vehicle-specific mileage standards. Until then, the company can choose to follow individual vehicle standards or use fleet rules.
That means the vehicles made at the Toledo Jeep Assembly complex off I-75 will get more miles to the gallon.
"We thought that this was an improvement," said Alan Reuther, legislative director for the United Auto Workers, which supported the new rules.
"We also thought that the overall increase in fuel economy was both reasonable and attainable."
The old system, he said, discriminated against companies making more large trucks, which get poorer mileage and thus together would lower the corporate average fuel economy.
The new rules, which are in effect but apply first to the 2008 model year, mean that the 2006 Liberty's EPA estimate of 23 miles per gallon must improve to 27 by 2011, and Wrangler's 16 mpg must jump to 28.
By contrast, Liberty's and Wrangler's top competitors, Ford Escape and Honda CR-V, have EPA-rated averages of 20 to 24 miles per gallon, respectively, and don't have as far to go to meet their targets of just over 27 mpg.
DaimlerChrysler AG's Toledo Jeep builds 14,160 Libertys and 6,460 Wranglers a month.
The rules will affect the new four-door Wrangler Unlimited and the Dodge Nitro to be in production this year at the Toledo Jeep plant. But it is unclear what their fuel economy targets will be.
How DaimlerChrysler will achieve higher miles per gallon in its vehicles is uncertain. Some improvement could be derived from new vehicle or engine designs and some from lighter-weight materials in the SUV that will not compromise safety.
Still, federal studies find, meeting the higher fuel targets will add perhaps $35 to $40 to the cost of the vehicle.
A key under the new rules is a vehicle's footprint, or the square footage determined by the length of the wheelbase (distance between the front and rear wheel) by average width of an axle.
Liberty's footprint is 44.2 square feet and Wrangler's 41.1 square feet. The figures for the four-door Wranglers and Dodge Nitro, to be made starting this summer at Toledo Jeep, haven't been determined.
Based on that footprint, the Transportation Department uses a formula to set mileage figures. It fluctuates based on the number of vehicles produced.
Automakers like Honda Motor Corp. that make many smaller vehicles with good fuel economy could continue to use the corporate fleet average for the next few years and switch to the individual standards by 2011, said
Don MacKenzie, an engineer with the Union of Concerned Scientists.
By contrast, Ford Motor Co. and General Motors Corp. make lots of fuel-hungry trucks and SUVs and likely will switch to the new rules immediately, he said.
DaimlerChrysler is right in the middle, he explained, making it hard to predict what it might do.
Max Gates, a DaimlerChrysler spokesman, said the firm hasn't decided how to proceed.
"The new fuel economy standard is going to be a challenge, and we're determined to meet that challenge," he said.
David Cole, director of the Center for Automotive Research in Ann Arbor, said the footprint standard is not a "killer regulation" that will hurt automakers or drive costs up considerably.
"I think they're doable," he said. "You're never going to get a manufacturer to admit it's a piece of cake because you're then going to get people jumping all over them saying 'Why didn't you do this sooner?'●"
Car companies, he said, know how to come up with multiple solutions to increase fuel efficiency.
"There's not a lot of screaming coming from the automakers. That's usually a sign they can do it," said John H. Johnson, an engineering professor at Michigan Tech University and member of a federal committee that readjusted the fuel economy standards in 1993.
As long as the fuel-efficiency targets are not more than a half mile per gallon jump every year or so, they will be attainable, he said.
"They know they'll have to put technology into their vehicles to get better fuel economy, otherwise they're not going to be able to sell these vehicles," he said.
Mr. Gates, the Chrysler spokesman, said design changes could contribute to better mileage.
"Aerodynamics have been a tremendous advantage for us for many reasons, but especially with fuel economy," he said.
But the automaker is wary of redesigning vehicles because even small changes could bring headaches on the production floor of the Toledo Jeep Assembly complex.
"A change may be only one station on the assembly line, but it has to be done very carefully because just changing the location of one small part can prevent the next station down the line from being able to install their part, and so on," he explained.
Until the company determines how it will meet the new standards, it cannot say whether the assembly line or worker procedures will be affected.
Chrysler could achieve better fuel economy by substituting plastic materials for steel, but it is limited in how much that can add to fuel economy, Mr. Gates said. "We think a lot of [fuel efficiency] has to come through the engine," he added.
Chrysler and other car makers are experimenting with an engine displacement system that shuts down two or more cylinders as power needs decrease. "You can get fuel economy gains of 10 percent or above with that," Mr. Gates said.
Under federal rules, automakers get credit toward fuel economy standards by making more vehicles that use more ethanol than gasoline.
The Union of Concerned Scientists said the new targets should be easy to meet.
"There is no shortage of technology that automakers could apply to meet standards that are much more aggressive, two or three times what they're being asked to do," said Mr. MacKenzie.
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