Even though the Metropolitan Transportation Authority has been around for half a century and is under the governor’s control, many New Yorkers labor under the misconception that the mayor runs the city’s subways and buses. When things go wrong, as they routinely do these days, he’s the one often criticized. So perhaps he (and the City Council) might try harder to earn some credit to balance out the blame, by doing more for mass transit. After all, the people most affected are the mayor’s constituents.

What’s needed from him are money and political will.

To his credit, Mayor Bill de Blasio agreed in 2015 to substantially increase the city’s contribution to the M.T.A.’s $29 billion five-year capital plan to $2.5 billion. For far too long, under several mayors, City Hall was unconscionably stingy, providing as little as $100 million or so a year to capital spending on infrastructure maintenance and improvement. As a coalition of mass transit advocacy groups observed last week, the need to secure that $2.5 billion, and perhaps even enhance it, is urgent.

Gov. Andrew Cuomo has pledged an extra $1 billion in capital funds next year, on top of his previous pledge of $8.3 billion, but where that new billion will come from is unclear. And counting on help from the Republican-dominated federal government seems pointless. So Mr. de Blasio needs to step up.

“He should do more because it’s his city,” said Gene Russianoff, a longtime leader of one of the advocacy groups, the Straphangers Campaign. The mayor could, for instance, designate a portion of property tax collections for mass transit, notably taxes paid by businesses; they have a big stake in getting their employees to work on time.