The hub of the president’s budget proposal for transportation is a $302 billion, four-year surface transportation reauthorization that he outlined last week during a trip to St. Paul, Minn.

Obama proposes to pay for the plan through a massive infusion of funds he envisions being created by corporate tax reforms. That new revenue that would augment the rapidly dwindling Highway Trust Fund, which gets most of its money from the federal gas tax.

(AP Photo/Jacquelyn Martin) (AP Photo/Jacquelyn Martin)

The budget document released Tuesday fleshed out his vision. It emphasizes a fix-it-first approach that would give funding priority to salvaging existing roads, bridges and transit systems rather than expanding their network.

The administration wants to invest $1.25 billion a year in the popular TIGER grant program to states and cities. It would create a new $10-billion, four-year program to address freight transportation bottlenecks that experts say impede U.S. competition in the global economy.

The White House plan would almost double funding — from $12.3 billion to $22.3 billion — for transit systems and intercity passenger rail.

In addition, the budget plan calls for spending $14 billion in discretionary funding on air, maritime, rail safety, and pipeline and hazardous material transportation activities. Key among that spending is $836 million for the Federal Aviation Administration’s NextGen system. NextGen, a project anticipated to revolutionize air travel, will get $186 million more from another proposed initiative.

The budget plan proposes lowering grants to large hub airports by $2.9 billion, using grant money to support smaller airports that do not benefit from airline user fees.