The MTA hopes to begin tolling drivers under its congestion pricing program June 30, Chair Janno Lieber said Friday.

The pioneering program, which aims to reduce gridlock in Manhattan while raising revenue for the MTA, has a $15 base fare for drivers traveling below 60th Street.

Lieber announced the start date during an appearance on ABC7. His plan comes with a big caveat: Pending lawsuits challenging the tolls could scramble the MTA's timeline.

Drivers who stick to the West Side Highway, FDR Drive and Battery Park Underpass are exempt from the new tolls.

The application process is also now open for low-income drivers who live in Manhattan and qualify for a toll discount, as well as drivers who transport someone with a disability or have a disability themselves.

"In 2017, New York's governor called congestion pricing an idea whose time had come. On June 30, barring any last ditch court interference, congestion pricing will become reality," Riders Alliance spokesperson Danny Pearlstein wrote in a statement. "Congestion pricing will be a win-win-win for all New Yorkers, commuters and visitors and bring better public transit, cleaner air and freer moving traffic. It cannot happen soon enough."

The agency expects to raise $1 billion a year from the tolls, which will be used to sell bonds worth $15 billion that will fund capital projects. The agency plans to upgrade signals across the system, buy new train cars, and make more subway stations accessible.

Lawsuits challenging congestion pricing have prompted the MTA to delay the start of those upgrades, citing the legal uncertainty. The MTA says the revenue from the tolls is "foundational" to its capital plans for the coming years.