After decades of delays and challenges, including a failed, last-ditch effort by the State of New Jersey to stop it in court, congestion pricing has arrived in the heart of New York City.

For the better part of a century, supporters of the tolling program have sold it as a way to reduce paralyzing gridlock while raising money from the drivers who contribute to it. The plan will help generate $15 billion for crucial upgrades to the region’s mass transit system.

Congestion pricing had been halted abruptly in June when Gov. Kathy Hochul of New York stopped it just weeks before its original start date. At the time, Ms. Hochul expressed concerns that the tolls would negatively affect New York’s economy, an idea that was disputed by some experts. She later revived the politically unpopular program one week after November’s general election, this time with reduced tolls that are scheduled to increase in the years to come.