An 81-year-old motorist struck a 62-year-old bicyclist in Brooklyn this afternoon — just seconds after he fled from an accident involving an empty yellow school bus, police said.

The bicyclist was hit around 4:24 p.m. at 18th Avenue and 72nd Street in Bensonhurst and was rushed to Maimonides Hospital in critical condition.

The elderly driver then struck a parked Range Rover before coming to a stop.

He had just slammed into the bus a block away before speeding off, authorities said.

He was taken to Lutheran Hospital in unknown condition. Charges were pending.