SAN DIEGO (CBS 8) - CHP has re-opened all lanes of the 5 north in Carlsbad after a woman was struck and killed by a pickup truck. Officials say she was running across the freeway. 

CHP says the victim was hit while running from the right side to the center divider in the northbound lanes of The 5. It happened near the Carlsbad Village Drive exit shortly before 4 a.m. 

It shut down the left passing lane for about an hour. A Chevy Colorado pickup truck, driven by a U.S. Marine corps captain from San Diego, struck a woman in her 40's. CHP says she was homeless. 

"The driver of the pick-up truck was uninjured. The driver is a 37-year-old male out of San Diego. The pedestrian at this point is not identified. She appears to be in her mid-40s and appears to be one of the local transients," Patrick Holt, CHP said.

The driver stopped and cooperated with detectives. He was shocked as the woman came out of nowhere on the busy freeway as traffic was building. 

CHP says the pickup truck driver was sober, but they're not sure if the victim was under the influence of drugs or alcohol. 

An autopsy has to be done to determine the woman's identity. Traffic is back to normal after this fatal crash.