NY Times:
 Cars at a standstill, thwarted by floodwater on the Long Island Expressway. Others forced to navigate an intersection in Williamsburg like amphibious vehicles on a Duck tour. Is that Carroll Street? Or is it a river?

Does New York City have an infrastructure problem?

How much rain fell?

Kennedy Airport in Queens got three and a half inches of rain, according to the National Weather Service. The area hadn’t received that much rain on a single July day since 1996.

The downpour dumped three inches of rain on Staten Island, and nearly that much in northwest Brooklyn.

Yet, if it were a contest, the city would have lost to the suburbs: To the north, West Nyack in Rockland County got 3.8 inches; to the east, Syosset in Nassau County was soaked by 3.9 inches.

A few inches of rain can swamp a New York street?

Yes. The amount of rain that falls, and how fast it falls, are important factors.