A long-awaited plan to reduce traffic in Manhattan’s central business district may charge passenger cars entering the area $15, with discounts for some drivers who already pay a crossing fee to come into the city, according to a draft report of a recommended tolling structure.

The program, called congestion pricing, is the first of its kind in the US and is expected to raise $1 billion a year to help modernize New York City’s aging transit system. A six-member Traffic Mobility Review Board has been studying how best to implement the new fee for months. The goal is to reduce traffic, decrease air pollution and encourage mass-transit ridership.

“This is very important and a big boost to the region’s economy,” said Carl Weisbrod, chair of the TMRB and a former director of New York City’s Department of City Planning, in an interview.

The Metropolitan Transportation Authority, which operates New York City’s subways, buses and commuter rail lines, is implementing the congestion pricing program and aims to begin charging drivers as soon as late Spring. But New Jersey Governor Phil Murphy has filed a lawsuit seeking to force the MTA to undergo a longer environmental review process, which may delay the new toll. 

Murphy slammed the tolling proposal late Wednesday, calling the structure “wholly inadequate.” 

“Placing an unjustified financial burden on New Jersey commuters is wrong,” he said in a statement. “We are left with no choice than to continue addressing our concerns through litigation.”

The MTA’s board will weigh in on the TMRB’s recommendations and has the ability to make adjustments. The board suggests that passenger vehicles pay $15 once a day to enter the central business district, while trucks pay $24 to $36, according to the draft report obtained by Bloomberg News. The fee would apply to drivers entering Manhattan South of 60th Street from 5 a.m. to 9 p.m. on weekdays and between 9 a.m. to 9 p.m. on weekends, with tolls 75% lower during the night.

The New York Times first reported the recommended tolling structure on Wednesday. 

The TMRB also proposes a $5 credit to passenger vehicles entering the district through four tunnels: Queens-Midtown connecting Manhattan to Long Island City, the Hugh L. Carey — a bypass to downtown from Brooklyn, and both the Holland and Lincoln which connect to New Jersey. Small trucks would get a $12 credit while large trucks and tour buses would receive $20.

“We really want to think of most drivers and the more we gave exceptions or exemptions or credits, the higher the toll would be for the many,” Weisbrod said. “And we really kept in front of us that we wanted the toll to be as low as we possibly could make it while achieving the goals of the program.”

The toll wouldn’t apply to taxi drivers and for-hire vehicles, but instead charge passengers per ride, $1.25 for taxis and $2.50 to those in ride-shares like Uber or Lyft.