A motorist was killed this week in a solo vehicle crash on the southbound Antelope Valley (14) Freeway in the Santa Clarita area.

Michael Paul Steen, 28, of Santa Clarita, was driving a 2002 Chevrolet 1500 pickup truck when “for an unknown reason, (he) made an unsafe turning movement and collided into the center median metal guardrail’’ near Technology Drive around 2:20 a.m., the California Highway Patrol reported.

“The Chevrolet continued to travel in a southerly direction out of control and subsequently overturned onto its roof and came to a rest on its wheels,’’ according to a CHP statement.

Steen died at a hospital.

It was unknown if alcohol or drugs were factors in the crash, the CHP reported.