FALLSTON, Md. (WJZ) -- A deadly head-on crash in Harford County caused major backups on Wednesday afternoon.

It happened around 4:15 p.m. on southbound Mountain Road, just south of Bel Air Road in Fallston.

Police say, for unknown reasons, a 17-year-old behind the wheel of a Ford F-250 pickup truck crossed over the center line and collided with a box truck.

The driver of the box truck was pronounced dead at the scene. The victim was later identified as 57-year-old Conrad Giovanni Gilbert, of Essex.

The 17-year-old was taken to Johns Hopkins Bayview Hospital.

Rt. 152 was closed for about three hours while troopers investigated.