Pennsylvania may soon join a regional program meant to limit greenhouse gas emissions and increase investments in green transportation.

A draft version of a regional cap-and-invest program for the transportation sector is open for public input until the end of February. Pennsylvania is one of 13 states, plus the District of Columbia, involved in the Transportation and Climate Initiative of the Northeast and Mid-Atlantic States, which is facilitated by the Georgetown Climate Center.

According to the draft plan, revealed last month, "allowances," which would represent a certain amount of CO2 emissions, would be auctioned off to suppliers and distributors of gasoline and diesel fuel. A company's number of allowances would represent the amount of emissions it's allowed to release. Proceeds from allowance auctions will go to other measures to fight climate change, with specifics left up to the states involved.

Pam Kiely, senior director of regulatory strategy for the Environmental Defense Fund, said cap-and-invest programs, and similar-cap and-trade programs, have worked in the past.

"This was the successful policy mechanism that allowed us to essentially eradicate the pollutants causing acid rain," Kiely said.

The only existing cap-and-invest program for the transportation sector in the U.S. is for the state of California, with Oregon poised to adopt a similar plan across sectors. Some traditional energy groups argue cap-and-invest and cap-and-trade systems will make energy more expensive for consumers. Critics on the environmental activist side of the issue say California's system concedes too much to industry.

But Kiely said cap-and-invest and cap-and-trade are effective ways to tackle climate change, because they encourage industry to become greener.

"The type of policy that's being evaluated by this group of states, a policy that would actually put emissions outcomes at the forefront, would be a huge step forward for the region," Kiely said.

In a statement, Pennsylvania's Department of Environmental Protection and the state's Department of Transportation said the state is looking to the initiative, known as TCI, as a potential way to address vehicle pollution.

"While the administration is committed to being a part of the TCI conversations, we will not make any decisions until the program is fully designed, modeling results are complete, and we get input from interested communities, businesses and other stakeholders," the statement read.

PennDOT and DEP officials directly involved in TCI were unavailable to comment for this story.