CHICAGO | Jason Kunst doesn't drive yet, but he understands the importance of keeping Ford and the two other American automakers in business making trucks, vans and SUVs, as well as cars.

Jason's father, Jeff, works at the Chicago Heights Ford Stamping plant, so the 15-year-old said he was happy to participate in a rally staged by the Big Three automakers and United Autoworkers at the Federal Plaza Thursday. He, his sister Jessica, and three other scouts from Lowell's Boy Scout Troop 697, played a special role in the event: demonstrating that large SUVs fill a need.

The rally promoted support for a bill sponsored by U.S. Reps. Baron Hill, D-Ind., and Lee Terry, R-Neb., that would hike Corporate Average Fuel Economy mandates to 35 miles per gallon for passenger cars by 2022 and at least 32 mpg for light trucks by the same year. Unlike the Senate version of CAFE legislation, the Hill-Terry bill sets one standard for cars and another for trucks, SUVs and vans.

Riding in a eight-passenger Ford Expedition SUV as it circled the plaza, filled with workers from the stamping plant, the Chicago Ford Assembly plant and the Belvidere Chrysler Assembly plant, the scouts with their leader and their backpacks were a shown as an example of why there is demand for large passenger vehicles.

"A 12-passenger van took to us to West Virginia to go white water rafting last year," Jason said. "If we had a Civic, it wouldn't have worked. We needed the passenger space and the cargo space. A small car wouldn't have worked. And my dad needs his job,"

The larger vehicles could be in jeopardy under the current Senate-approved CAFE legislation that increases average fuel economy to 35 mpg for cars and trucks combined by 2020, according to the UAW and U.S. automakers.

The Terry-Hill bill supporters contend having all vehicles lumped together in one standard would hurt Ford, Chrysler and General Motors and put UAW jobs at risk because the Big Three produce more trucks, vans and SUV than their competitors.

Under the Senate legislation, which will be debated when Congress resumes in September, Ford, Chrysler and GM would be forced to cut production of large pickups and SUVs by 60 percent, according to a Lehman Brothers study.

Proponents claim the Terry-Hill bipartisan bill still would require automakers to improve fuel economy by 30 to 40 percent, and in doing so, reduce greenhouse gasses and U.S. reliance on foreign oil.

Jerry Roper, president of the Chicagoland Chamber of Commerce, said the rally was basically a media event offered to attract the attention of Illinois and Midwest legislators.

"We need to educate elected officials on what happens outside the Beltway," Roper said. "We need to bring real examples of why issues like Hill-Terry are important to people. CAFE has a real impact on the amount of vehicle our automakers will be able to produce and under the Senate CAFE we face the loss of jobs."

There are 100,000 auto-related jobs in the Chicagoland area, said Mark Haasis, UAW Illinois legislative director.