An intoxicated off-duty detective was involved in a car accident in Queens that left one person critically injured early Sunday, police sources said.

Neville Smith, 32, who works in the 48th Precinct in the Bronx, was preparing to enter the southbound lanes of the Van Wyck Expressway when he rear-ended another car on the entrance ramp near Rockaway Boulevard around 4 a.m.

The impact badly injured a 22-year-old woman in the other car, police said. She is in critical condition at Jamaica Hospital.

Two other occupants, a 21-year-old woman and 20-year-old man, were rushed to the same hospital with minor injuries.

Smith suffered some minor head and neck injuries and was taken to Jamaica Hospital before being charged with DWI, sources said.

He later was charged with several counts of vehicular assault, assault and refusal to take a breath test.