"We know that Maryland desperately needs more transportation funding, but we would have to see balance and fairness," said Lon Anderson, government affairs director for AAA Mid-Atlantic. "The governor's plan goes after motorists in a big way."

The proposal is also getting pushback from lawmakers in rural counties. At a hearing Friday at which three county executives testified in favor of the plan, Del. Kathy Afzali, a Frederick County Republican, noted that there were no elected officials present from Maryland's rural areas.

"That sends a message to me that this is an urban agenda," she said.

The numbers needed to pass a bill are 24 votes in the state Senate and 71 in the House of Delegates.

It is unlikely that any of those votes will come from Republicans. In states such as Virginia, where they hold majorities, GOP legislators have provided votes to raise taxes for transportation. In Maryland, as recently as 2004, with a Republican governor asking for their help, the state's GOP lawmakers supported a transportation revenue package based largely on an increase in the motor vehicle registration fee.

This year, as a heavily outnumbered minority, Republicans have little incentive to get behind a proposal that is politically toxic in their conservative districts. Not even the prospect of a ribbon-cutting in his or her district is likely to entice a Republican lawmaker to risk a primary challenge.

That leaves a pool of 98 Democratic delegates and 35 senators in which the governor and legislative leaders can fish for votes.

The governor, the speaker and the Senate president will likely try to assemble just enough votes to pass the bill while letting their more conservative Democratic members off the hook.

In the House, the base of a coalition in favor of the gas tax plan probably would have to come from the all-Democratic delegations from Baltimore and from Montgomery and Prince George's counties. They are the jurisdictions with the greatest transit needs and traffic congestion, and where lawmakers would face the least political risk from casting a "yes" vote.

Those jurisdictions would provide 65 of the needed 71 votes if the speaker's vaunted whip system could keep all of those members in line. The leaders will look for the rest of the votes in such places as eastern Howard County, western Baltimore County, the city of Frederick and increasingly Democratic Charles County, where rapid growth has led to traffic congestion.

The math is similar in the Senate, except that Miller might need to muster 29 votes to break a filibuster — something he always seems able to do.

michael.dresser@baltsun.com

Proposed rise in gas taxes

•Estimated 2 cent increase to price of a gallon of gas July 1

•Another 7 cents in 2014

•Another 7 cents possible in 2015

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