Del. Gerard F. Devlin got a road for the University of Maryland. Del. Richard Palumbo got a bridge for Hyattsville. Del. Lorraine M. Sheehan got money for a mental health clinic. Del. Lucile Maurer got assurance that her concern about bond projects would be considered.

And Gov. Harry Hughes got his gasoline tax.

Such was the wheeling-and-dealing in the General Assembly today as the House Ways and Means Committee approved the governor's 4.5 cents-a-gallon tax increase on gasoline. The vote was 14 to 9.

So pervasive was the level of horse-trading that before and during the committee vote, legislators on both sides joked openly about trading their votes for their pet transportation projects. When one "yes" voter, Del. Raymond E. Beck (R-Baltimore), raced back into the committee room from a phone call just in time for the roll call, someone jokingly called out "One more bridge!"

"Six more potholes," Devlin cried out like an auctioneer.

The committee vote was considered the crucial hurdle for the controversial election-year tax, which now goes to the House floor, where it is expected to pass. The proposal already has passed the Senate.

For the past few days, Hughes, personally and through his staff lobbyists and legislative leaders, had been doling out personal favors and commitments like a State House godfather, reaching into his satchel of political goodies and making offers to legislators they could not refuse.

Maurer (D-Montgomery) had been trying for two months to get assurances from someone that state corporate tax revenues are not being tied up as collateral for transportation bond projects. Thursday night, she got the governor's personal assurance, via a hand-delivered letter to her office, and today she voted for the gasoline tax.

"It's clear that he needed my vote," Maurer said. "Two months ago, nobody listened to me. But I said I wouldn't vote for a gas tax without this."

Sheehan (D-Prince George's) said she didn't want a gasoline tax increase without assurances that corporations would not get a tax cut because of federal tax law changes. And she wanted to make sure there was enough money in the budget to fund her favorite project, community-based programs for the mentally retarded.

"It's not a deal," she said before the vote. "It's a matter of equity." She said she got assurances that Hughes would at least support a bill to prohibit corporations from trading off their tax credits to each other. The governor telephoned this morning, Sheehan said.

Devlin (D-Prince George's), the committee vice chairman, said he got the transportation department to make building a badly needed new road at a University of Maryland science center near Bowie a high priority. As vice chairman, Devlin said he would have voted for the tax anyway. So why the trade? "Because I can convince other people to vote for it," he said.

And Palumbo (D-Prince George's) made a simple request: That the transportation department move up the scheduled construction date to 1985 from 1987 for a bridge over some railroad tracks in Hyattsville. He said he got a sympathetic ear, but no promise. He voted for the tax.

So intense was the bargaining atmosphere over this crucial transportation tax that when Maurer met with Hughes this morning to discuss her concern over corporate tax money, she had to assure the governor, "I don't want anything!" Hughes laughed aloud, she said.

Before the vote, a dejected-looking Del. Paul E. Weisengoff (D-Baltimore), leader of the routed opposition, predicted solemnly, "We're going down to ignominious defeat."

"They worked hard," he said. "They're going to be building a lot of roads."

Legislators and transportation department lobbyists were reluctant to discuss publicly what roads and bridges were offered for votes. But one lobbyist added that most projects are already included in the department's list of priorities, with the bargaining limited to when things will be done and in what order.

"We decide the issue on its merits," Devlin said. "They the transportation department have a lot of leeway. These are mostly things they've been promising to do for years anyway."

"You just build the roads that are needed as they are needed," said Lou Panos, the governor's press secretary, who indignantly denied that Hughes would soil his hands with anything so blatantly political as vote trading. "We promised to carry out the program that has already been promised."

"There's been no last-minute jockeying or horse-trading," he said. "That's a poor test of friendship."

One "no" vote Hughes unsuccessfully lobbied was Del. A. Wade Kach (R-Baltimore County). "He called me up to his office," Kach said. "I wore my best suit. I thought he was going to offer me lieutenant governor. He only wanted to persuade me to vote for his gas tax."