The city’s most dangerous pedestrian crossings are being outfitted with “countdown” signals, the Department of Transportation said yesterday.

The agency has begun installing the first wave of countdown signals — which let pedestrians know how much time they have to cross the street — at 43 high-crash intersections. Eventually, there will be 1,500 across all five boroughs.

“Crossing the street doesn’t need to be a guessing game,” DOT boss Janette Sadik-Khan said.

The signals already are at the intersection of Flatbush Avenue and Fulton Street in Brooklyn, where 32 pedestrians were struck from 2005 to 2009.

Under the pilot, 12 timers will be installed in Manhattan; 13 in Brooklyn; seven in The Bronx; eight in Queens and two on Staten Island.