"You've got to do it. What's the point of saving money and having bridges collapsing?" she said.

The initial impact of the gas tax increase will be relatively modest for drivers of private vehicles. AAA estimates that the average Maryland motorist uses 47.6 gallons of gas a month, which translates to an added $1.66 in taxes monthly, or just under $20 a year.

The gas tax will increase in stages through mid-2016, when the state projects it will reach 42.5 cents a gallon — costing the average motorist just over $9 a month, or $110 a year, more than now. The increase could be reduced by 7 cents a gallon — leaving it at about 35.5 cents — if Congress passes a bill by 2015 allowing Maryland to collect taxes on Internet sales by companies such as Amazon.

However they feel about the gas tax increase, Marylanders are beginning to see some payoff from the increased revenue. When O'Malley signed the transportation bill May 16, he announced $1.2 billion in projects made possible by the new revenue.

They include an expansion of MARC Penn Line commuter train service to weekends, design money for light rail lines in Baltimore and the Washington suburbs, and seven major highway projects. They include a reconstruction of the Leeds Avenue interchange on the Beltway in Baltimore County and the widening of U.S. 29 in Howard County.

Two weeks later, when O'Malley named former Baltimore County Executive Jim Smith as state transportation secretary, he announced a $90 million project to widen the Beltway from U.S. 40 to Frederick Road — the type of congestion-relief work that had nearly ground to a halt in recent years.

"Every morning is a tie-up that goes all the way up to [Interstate] 795 in the Pikesville-Owings Mills area. And that is going to be remedied," Smith said.

Motorists will understand the need for the gas tax increase as more projects get started, he said.

"They're going to see — fairly quickly — what they're getting for their money. And that is just the start," Smith said. "One of my biggest challenges in this role will be to handle the pent-up demand for all the projects that have been in the queue."

While the gas tax increase was up to the discretion of the legislature, the 2011 decision to raise tolls was unavoidable, Smith said.

"It was required in order for us to maintain our systems and meet our safety standards as well as our maintenance agreements," he said. In addition, he said, the authority had an obligation to raise money to pay bondholders for the money it borrowed for two "mega-projects" — the $2.6 billion Inter-County Connector in the Washington suburbs and the $1 billion Express Toll Lanes project on I-95 northeast of Baltimore.

As a result of the toll increases, the cash cost each way of using any of the three Baltimore Harbor crossings will go from $3 to $4. The Susquehanna River crossings on I-95 and U.S. 40 will jump from $6 to $8 — each collected northbound only. Tolls on the Bay Bridge and the U.S. 301 bridge over the Potomac, also collected in only one direction, will rise from $4 to $6.

Tolls on the ICC are not affected, because charges for using that road, which connects I-95 with I-270, are pegged to the level of traffic.

For DiBlasio, the toll increase means the difference between using the Fort McHenry Tunnel and navigating through city streets on his way to work at the University of Maryland's downtown campus. He said he turned in his E-Z Pass on Monday — and had a lot of company when he did so.

"It's not even worth the gas or the wear and tear on your car to take the tunnel anymore," said DiBlasio, a computer technician who estimated that the city route would add 10 minutes to his commute. The toll increase would have raised the cost of commuting for him and his wife, who is keeping her account, by about $60 a month, he said.

He wishes the authority had raised the tolls in regular intervals over the years rather than waiting and imposing two large increases in two years.

"I don't have time to adjust it for my budget," he said.

There is some good news for motorists. According to the transportation authority, no further increases are in its six-year-forecast. And taking effect the same day as the gas tax increase will be a law facilitating public-private partnerships — a method state leaders hope to use to build large infrastructure projects while minimizing future tax increases.

Ragina Averella, Maryland spokeswoman for AAA Mid-Atlantic, said that at least the gas tax increase isn't taking effect in the middle of a price spike. This week the average price per gallon of unleaded gasoline was hovering around $3.50, about where it was the month before.

"The only silver lining in the cloud is that gas prices are stable at this time and in fact should be declining if there are no major refining issues or supply issues," she said.