A coalition of private groups and government officials on Wednesday called on Sacramento to stop using transportation funds to balance the state budget, and warned that L.A. County could lose nearly $300 million in state gas tax monies earmarked for street, highway and public transportation projects in the coming fiscal year.

Mobility 21, led by the Los Angeles Area Chamber of Commerce and the Metropolitan Transportation Authority in partnership with the Automobile Club of Southern California, wants revenues from Prop 42 gas taxes and other transportation funds to be used to fund projects that will ease congestion, such as extending the planned Exposition Light Rail Line to Santa Monica.

Voters approved Prop 42, which requires state sales taxes on gasoline and diesel fuel be used only for transportation programs, in March 2002. However, in a fiscal emergency Prop 42 can be suspended. Under this loophole, more than $2 billion has been redirected to the state’s General Fund since 2003, said Mobility 21.

And in the last three years, Sacramento has siphoned off $5.5 billion in transportation funding statewide from such projects, said Metro Chief Executive Roger Snoble.

“It would be typical of Sacramento politicians to raid Proposition 42 funds once again to balance their budget on the backs of local cities,” said Mayor Jim Hahn. “That money belongs to the people.”

Mobility 21 also worries that, there are many local transportation projects that could be kept on hold indefinitely if Prop 42 funds are diverted next year. Among them are construction of a northbound carpool lane on the San Diego (405) Freeway between the Santa Monica (10) and Ventura (101) freeways, and a Crenshaw Corridor transit way.