The landmark initiative, which began on Sunday, is designed to reduce traffic congestion, improve air quality and raise funds for much-needed public transit upgrades.

New York’s much-debated plan to charge drivers to enter the center of Manhattan is set to take effect Sunday just after midnight, following years of bureaucratic and legal roadblocks. The goals of what is known as “congestion pricing” are to reduce gridlock and pollution and raise revenue for public transit.

A dizzying array of exemptions, credits and existing tolls makes it tricky to calculate how much drivers will actually pay when they enter Manhattan south of 60th Street.