A liberal think-tank says if Virginia raises taxes for transportation, it should provide relief for those least able to afford them: the working poor.

In a study released this morning, the Commonwealth Institute says that proposals to increase the sales and gasoline taxes will disproportionately hit those earning less than $18,000 a year.

According to the institute's figures, for a Virginian with an income of $17,900, a 10-cent rise in the fuel tax -- now 17.5 cents per gallon -- will cost another $32 per year. A penny increase in the sales tax -- currently a nickel on the dollar -- cuts earnings by $67.

Michael Cassidy, director of the Commonwealth Institute, says the legislature should offset these increases with tax breaks, including a refundable sales-tax credit.

The General Assembly returns to Richmond on June 23 for a third attempt in as many years to fashion a fiscal fix for transportation. Last year's road-and-rail package has been gutted of nearly $600 million.

It was trimmed by $65 million with the repeal of unpopular bad-driver fees. And a Virginia Supreme Court decision means regional authorities in Hampton Roads and Northern Virginia cannot issue about $500 million in bonds for transportation improvements in those traffic-clogged areas.

--Jeff E. Schapiro