A new toll on 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.

Preliminary traffic data is giving promising if occasionally mixed signals for the early days of congestion pricing’s impact on Manhattan’s busiest streets, with travel times down at Hudson River crossings but speeds within the zone slightly slower at key times of day year over year.

Congestion pricing was introduced on Sunday morning in the center of New York City — despite a late attempt by New Jersey to stop it in court.

New York City's first-in-the-nation congestion pricing toll program is being linked to a slight jump in the number of commuters using subways.

Experts warn it's too early to tell what impact the tolls are having on Manhattan's notorious gridlock, but the view from the streets shows signs the program could be working.