The city promises to continue Operation Move-Along one day a week, along with the weekly anti-spillback initiative that began this summer. The latter is aimed at reeducating drivers not to enter an intersection if they cannot drive all the way through.

As of late last week, that question was probably on the lips of 6,552 drivers who had been caught on just three days in the city's latest crackdown on the scourge of gridlock, or what traffic specialists call "spillback," in which a single intersection is blocked by cars that fail to get through before the light changes. (Strictly defined, gridlock occurs when spillback ties up traffic around an entire square block and offending drivers end up pretty much blocking themselves.)

Spillback occurs when a street block is so jammed with slow-moving or stopped vehicles that it has no room for any entering traffic, which frequently "spills back" or gets caught in the intersection of or the crosswalks.