The patterns are familiar, said Sam Schwartz, the former city traffic commissioner and engineer known as Gridlock Sam.

WSJ: Decoding Traffic In a Jammed City

That could be harder than it sounds, said Sam Schwartz, a former city traffic commissioner in the 1980s.

WSJ: Bridge Traffic On Walkway Stirs Concern

The highways that ring Manhattan along the water sit atop a series of tide gates that are designed to drain water from the road and keep water from gurgling up from below, said Sam Schwartz, a former city transportation commissioner who now works as a consultant.

WSJ: New York City Transit System Braces for Water Surge