A 70-year-old man behind the wheel of a SUV was critically injured Saturday when he slammed into a parked tractor trailer in Brooklyn, police said.

The unidentified victim was driving a 2001 Jeep SUV southbound on Third Avenue near 50th Street in Sunset Park around 11:15 a.m. when he collided with the parked, unoccupied tractor trailer, the NYPD said.

The 70-year-old man was taken to NYU Langone Hospital with critical injuries, an NYPD spokeswoman said. No one else was hurt.

The NYPD’s Collision Investigation Squad is probing the incident.

The unit is looking into whether the victim had a medical episode prior to the crash, a police source said.