LAKE RONKONKOMA - Police are investigating a crash on the Long Island Expressway that has left a teen with serious head injuries. 

Police say a 21-year-old man was driving westbound on the expressway just after 10 p.m. yesterday when he lost control and hit a guardrail. 

The passenger, Ryan Brennan, 17, of Deer Park, was airlifted to the hospital with brain injuries. 

The driver and another passenger had minor injuries.