A motorcycle struck a metal guardrail on Angeles Crest Highway, injuring the man driving it and killing the woman on the back of the bike, authorities said Monday.

The crash was at 11 a.m. Sunday on Angeles Crest Highway south of Big Pines Highway, California Highway Patrol Officer M. Chapman said.

The 68-year-old man driving the 2013 Harley-Davidson motorcycle lost control of the vehicle for an unknown reason, causing it to leave the roadway and crash into a metal guardrail, Chapman said. The man and a 62-year-old woman were both ejected from the motorcycle.

Both were taken to Pomona Valley Hospital where the woman was pronounced dead and the man was treated for major injuries, the officer said.

Neither alcohol nor drugs were suspected factors in the crash, Chapman said.

A SigAlert was issued shutting down Angeles Crest Highway at 12:20 p.m. and the roadway was reopened at 2:01 p.m.

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