A new toll for drivers entering the core of Manhattan brought modest but measurable traffic reductions to New York City’s heavily-gridlocked streets in its first week of operation, according to preliminary data released Monday by the state's transit authority.

The scheme aims to ease New York's notorious traffic problems and raise billions for the public transport network. Most drivers are charged $9 once per day to enter the congestion zone at peak hours, and $2.25 at other times.

Vehicles pass a sign on 9th Avenue announcing New York City's congestion pricing program in effect charging drivers for entering the central business district in Manhattan below 60th street in New York City,