The westbound lanes of I-285 in Cobb County were shut down for more than four hours Thursday morning after a pedestrian was struck by multiple vehicles and killed, police said.

The shutdown caused major delays through the northwestern suburbs even after the lanes reopened at 9:20 a.m., according to the WSB 24-hour Traffic Center.

The interstate was closed at Cobb Parkway just before 5 a.m. after the man, identified as 29-year-old Dustin Dalton of Canton, was hit and killed, Cobb police spokesman Sgt. Wayne Delk said.

Police said the man was struck by several vehicles, including a tractor-trailer, and that the “scene extended across all westbound lanes.”

It’s still unclear why the man walked onto the interstate, Delk said.

The ramps from I-75 to I-285 West were closed as authorities investigated the fatal wreck. As a result, the Perimeter was jammed for the entire morning rush, and the ride on I-75 South was backed up through Kennesaw.

The gridlock prompted traffic reporters to suggest that drivers avoid Atlanta's busiest, and deadliest, interstate Thursday morning.

The delays did not start to clear up until about 10:30 a.m.

The wreck remains under investigation and anyone with information is asked to call Cobb police at 770-499-3987.

— Please return to AJC.com for updates.

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