A motorist with a flat tire was killed Friday morning when he walked across I-285 to read a road sign, Atlanta police said.

Traffic investigators believe Alberto Henderson, 48, of Baltimore, Maryland, was trying to pinpoint his location after blowing a tire on the inner loop near the ramp to I-20 in Fulton County. He was struck by a tractor-trailer about 2:15 a.m.

“The driver stayed on scene and is cooperating with investigators,” police spokesman Officer Steve Avery said. “The investigation is continuing but no charges are anticipated in this accident.”

The resulting investigation shut down the northbound lanes of I-285 for four hours Friday morning. The ramp from I-20 West to I-285 North was also closed, the WSB 24-hour Traffic Center reported.

The lanes did not reopen until 6:15 a.m., according to the Traffic Center.

During the shutdown, inner loop traffic was forced off I-285 at Cascade Road. The backups caused Westside commuters to crowd onto the Downtown Connector and Fulton Industrial Boulevard, the Traffic Center reported.