Mayor Bloomberg will be in Washington today in a last-ditch attempt to lobby for his traffic tax plan and to push for increased gun control measures.

The trip comes just days before Monday’s federal deadline on his congestion pricing plan. Yesterday, the mayor said time is “running out” and that if state leaders don’t approve the plan they will jeopardize the federal funding that is on the line for major mass transit upgrades.

“Our window of opportunity will close roughly one week from today,” Mr. Bloomberg told members of the New York Building Congress.

The state Senate majority leader, Joseph Bruno, is scheduled to join Mr. Bloomberg for a meeting with the undersecretary for policy at the U.S. Department of Transportation. The two will likely assure the federal officials that there is support for the plan even though the Assembly has not yet backed it.

Meanwhile, Transportation Alternatives, a group that supports the congestion-pricing plan, released a report that found the majority of low- and middle-income New Yorkers would benefit from it because they take mass transit. The report is part of the flurry of last-minute jockeying to cast either a positive or a negative light on congestion pricing. Indeed, it countered a report released by Assemblyman Richard Brodsky, an opponent of the plan, which found that the charge would be a financial burden for low- and middle-income drivers.

Mr. Bloomberg will also use today’s trip to Washington to pressure Congress to drop the socalled Tiahrt Amendment from a bill the House Appropriations Committee is scheduled to vote on later this week. A Senate committee approved the Tiahrt provision — which limits how local police can use federal gun trace data — last month despite opposition from Mr. Bloomberg and his Coalition of Mayor’s Against Illegal Guns.

The mayor’s gun-control push follows yesterday’s shooting of two New York City police officers in Brooklyn. During an appearance at Kings County Medical Center, Mr. Bloomberg said: “At the very least, the terrible events of this morning are proof once again of that fundamental truth we have learnt again and again: guns, when they fall in the hands of the wrong people, have tragic consequences.”

The mayor will appear today with members of his coalition along with police officials and members of Congress, his office said.

Yesterday, a member of the mayor’s gun coalition, Henry Moore, of Oldmans Township, N.J., population 1,800, dropped out of the group.

When asked about the resignation of Mr. Moore, a spokesman for Mr. Bloomberg, Jason Post, said that far more mayors are joining the coalition, which has more than 220 members, than leaving. He said the mayor of Kingwood, N.J., joined the group yesterday, meaning the “net impact on our membership is zero.”