Police say 33-year-old Brian Mullady was driving south on Smithtown Avenue when his Dodge pickup truck crossed into oncoming traffic, striking a Cadillac Escalade.
Mullady and a passenger in the Escalade, Andrea Giattino, 19, of Stony Brook, were both pronounced dead at the scene.
The driver of the Escalade, Justin Quaranta, 23, of Ronkonkoma, was transported to Brookhaven Memorial Hospital Medical Center where he was treated and released.
Giattino and her boyfriend, Justin Quaranta, were heading back from a day out with his family.
Giattino was a sophomore at Suffolk County Community College.
She was an honor roll student who volunteered in her free time, a young woman who was wearing her seatbelt at the time of the crash inexplicably taken.
Police say it's unclear whether drugs, alcohol, or speed were involved.
Police are asking anyone with information on this crash to call 631-852-8552.