Massachusetts and 11 Northeastern and mid-Atlantic states are jointly looking to scale back on gasoline and diesel emissions as part of an effort to implement a regional “low carbon” transportation policy, according to a draft policy framework released on Tuesday by the Transportation Climate Initiative.

The Transportation Climate Initiative is proposing through the draft plan a cap on motor emissions by requiring that state fuel suppliers hold allowances based on emission levels that have yet to be determined. A regional organization would then auction the allowances in the “cap-and-invest” scheme, and each jurisdiction — or state — would decide how to invest the program’s proceeds based on their transportation needs.

Participating states include Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont and Virginia.

The initial cap would be set using a combination of baseline emissions for three recent years and projected emissions, then decline over time, according to the plan. TCI is looking to begin the program as early as 2022 and reach a target emissions level in 2032.

Massachusetts transportation and energy officials have been participating in working to shape the details of the plan with the hopes that the states can sign on to a final memorandum of understanding in the spring of 2020.

“We’ve completed an enormous amount of work to date and received a lot of input from organizations across the region,” said Kathleen Theoharides, secretary of the Massachusetts Executive Office of Energy and Environmental Affairs. “This (plan ... gives us the opportunity to make significant reductions in greenhouse gas emissions.”

According to the Commission on the Future of Transportation In the Commonwealth Report signed into law by Massachusetts Gov. Charlie Baker, the transportation sector is the “largest and fastest growing emitter of greenhouse gas emissions."

"Almost 30 percent of all GHG emissions in the United States came from the transportation sector in 2016 — and in Massachusetts, almost 40 percent of GHG emissions in 2015 came from transportation infrastructure and vehicles, with nearly half of the contribution coming from passenger vehicles alone,” the report states.