WASHINGTON The drive by Democrats in Congress to create a cap-and-trade system to limit carbon emissions has become one of the most contentious issues being debated in the current session.

While there remains some doubt whether or not Congress will be able to pass a climate-change bill that will clear both houses, one thing is certain: If a bill does pass, diesel fuel will become more expensive.

And that possibility has become a key during Senate debate.

Of course, thats part of the whole idea behind cap and trade: Raise the cost of carbon-based energy to encourage investment in cleaner energy and promote more efficient use of energy, with the long-term objective of slowing global warming and decreasing U.S. dependence on foreign oil.

There are lots of arguments for and against this idea, all of which are being debated at length on Capitol Hill as Congress considers the climate-change legislation.

But the possibility of a steep jump in diesel prices isnt likely to win the legislation much support among motorcoach operators.

Petroleum suppliers have said diesel fuel could go up by as much as 88 cents a gallon under the cap-and-trade bill passed by the House.

Of course, many in the motorcoach industry support efforts to reduce greenhouse gas emissions and improve fuel efficiency. After all, motorcoaches that are more fuel efficient cost less to operate and reduce the industrys carbon output.

Many operators have taken their own steps to reduce fuel consumption by educating drivers to be fuel conscious, and reducing idling and using more fuel efficient tires.

Beyond that, however, the industrys hands are tied. Motorcoach operators don't build engines and they don't refine fuel. But they do pay the price of any increased fuel cost due to climate-change legislation.

The chairman of the Senate Environment and Public Works Committee, Sen. Barbara Boxer, D-Calif., said her committee will draft its own legislation.

However, she supports the cap-and-trade approach, and has challenged the prediction of steep increases in fuel prices.

Meanwhile, ground transportation lobbyists continue to push for changes to the proposed climate-change legislation, saying it must:

Address the need to improve highway infrastructure to reduce carbon output

Contain provisions for carefully monitoring the proposed carbon trading markets to assure transparency and to prevent excessive speculation

Preempt regional, state and local carbon laws to prevent a jumbled patchwork of laws that impede transportation efficiency

Provide oil refiners with appropriate free carbon allowances for fuel production to help offset significant price increases for refined products