State and city officials have started entertaining a new method of funding dire repairs to the subway, the New York Times reports. In addition to implementing congestion pricing in some areas of Manhattan, some local leaders are leaning into using the taxes from legalized marijuana for boosting subway repairs.

The MTA estimates it will cost upwards of $40 billion over ten years to bring the subway into the 21st century (or, at least, some kind of working order.) But $40 billion is just a drop in the bucket of what taxes from legalized marijuana in New York are projected to reach: A report released in June by the governor’s health commissioner found that legalizing pot could generate up to $670 million in annual tax revenue for the state.

One of the major benefits of using tax revenue from pot is that, as a new revenue stream, it would not be diverting funds from other public services. A new report by NYU’s Rudin Center for Transportation Policy and Management, authored by Mitchell L. Moss, also notes that the revenue source has the potential for growth in future decades.

A handful of local officials have informally endorsed the idea—City Council Speaker and possible 2021 mayoral candidate Corey Johnson among them. “The biggest issue we hear about as elected officials is the state of the subway system,” Johnson told the Times. “To be able to tie these things together is something that could be highly impactful and potentially transformative.”

Governor Andrew Cuomo, who oversees the MTA, has neither announced support for or opposition to the concept. But using tax revenue from marijuana legalization is one of about a dozen ideas being explored by a 10-person panel called the Metropolitan Transportation Sustainability Advisory Workgroup that’s been convened by state lawmakers. Those on the panel include State Senator Michael Gianaris of Queens, who supports marijuana legalization; former City Council Speaker Melissa Mark-Viverito; and MTA Board Vice Chairman Fernando Ferrer.

In June, a study commissioned by Governor Cuomo by the state’s health commissioner recommended legalizing marijuana, citing the $670 million in annual tax revenue. The Rudin Center report also found that 62 percent of Americans now support legalizing marijuana. “[T]he situation on marijuana is changing,” Cuomo said, noting that the neighboring states of Massachusetts and New Jersey are moving forward with plans to legalize pot.

The Rudin Center report put out some searing words on the issue: “New York State is not a leader, but it need not be a laggard.”