Three pedestrians and cyclists were killed in traffic collisions across three boroughs Wednesday night — two of them by drivers who fled the scene.

Chaim Blum, 23, was standing on a Brooklyn sidewalk when a minivan careened into him after it was struck by another minivan around 9:10 p.m. Wednesday, according to police.

The incident happened at 13th Avenue and 50th Street in Borough Park.

The victim, a neighborhood resident, was on the southeast corner when one of the minivans T-boned the other in the intersection, sending the vehicle spinning towards the sidewalk, police said.

Blum was found lying on the street with trauma wounds and was pronounced dead at Maimonides Medical Center.

Neither of the drivers — who were both 27-year-old men — were arrested, according to the NYPD.

Less than 20 minutes later in Manhattan’s Spanish Harlem area, a 62-year-old man was struck by a car whose driver kept on going.

Oscar Nieves was crossing Third Avenue at East 122nd Street when a grey SUV plowed into him and continued driving north, the NYPD said.

Nieves, who lived just feet from the hit-and-run scene, was found lying on the street suffering from head and body trauma.

He was pronounced dead at Harlem Hospital.

Cops were searching for the driver responsible for taking his life.

At 11:20 p.m. in the Bronx, a 64-year-old man on a bicycle was killed by a hit-and-run driver as he rode his bike in the crosswalk on Williamsbridge Road at Pierce Avenue in Morris Park, investigators said.

The unidentified cyclist was pronounced dead at Jacobi Medical Center, and police were hunting for his killer, who they believe was behind the wheel of a white pick-up truck.