Cincinnati Fire and EMS, Associated Press
In this photo provided by the Cincinnati Fire and EMS, workers stand near the scene following a highway overpass collapse in Cincinnati, Monday, Jan. 19, 2015. The Cincinnati Fire Department says the bridge was undergoing demolition at the time of the collapse.

CINCINNATI — A collapsed overpass covered southbound lanes of Interstate 75 with hundreds of tons of concrete and steel Tuesday, following a construction accident that killed a worker and injured a tractor-trailer driver.

Authorities identified the worker as Brandon William Carl, 35, of Augusta, Kentucky. The Hamilton County coroner's office will do an autopsy to determine cause of death; Cincinnati fire officials say the body was recovered from debris some four hours after the accident Monday night.

The tractor-trailer driver suffered minor injuries when his rig ran into the collapsed section of overpass, which was being demolished. His name wasn't released.

Cincinnati authorities said casualties could have been much higher had the accident occurred during the day.

The Ohio Department of Transportation said that Westerville, Ohio-based Kokosing Construction Co. was in charge of the construction. A message was left with the company Tuesday.

Gary Middleton, acting deputy director of the department's southwest Ohio district, said his experience has been that Kokosing is a "very safety-conscious" contractor with high ratings.

Transportation officials said southbound lanes of the major north-sound artery, which carries more than 178,000 vehicles a day, could be closed at the accident site for 48 to 72 hours.

"The debris needs to be removed and we have to determine if there is damage to the pavement," spokeswoman Sharon Smigielski said. "The cause is still under investigation."

Demolition work was going on Monday night to remove the overhead exit ramp that had recently been replaced by a new one. The structure came down at about 10:30 p.m. some five miles north of the Ohio River.

The ramp had been a left-hand exit from northbound 75 that carried traffic over the southbound lanes to Hopple Street. The new ramp exits to the right from northbound 75 near the University of Cincinnati.

Commuters to downtown Tuesday morning were diverted to Interstate 71 south, where traffic slowed through the morning. Motorists headed to Kentucky could take the Interstate 275 loop around the city. Southbound side streets also were congested into the afternoon.

The ramp replacement was part of a yearslong project to increase capacity and safety on a congested, accident-prone section of the interstate. Nighttime closures of northbound I-75 for work had been planned for this week, but state transportation officials said that schedule could be changed.

Cincinnati Police Chief Jeffrey Blackwell said late Monday that something went "terribly wrong."

"The big-rig driver is very lucky; in a matter of seconds his fate would have probably been different," Blackwell said.

A nearby resident said the collapse rattled his house.

"Just heard a thud, and the house shook," Casey Wright told WLWT-TV. "It felt like an earthquake. I'm sure the whole neighborhood felt it."

The Cincinnati Fire Department said the worker's body was removed early Tuesday, after airbags were used to lift the wreckage.

Associated Press writers Andrew Welsh-Huggins and Ann Sanner in Columbus and Lisa Cornwell in Cincinnati contributed. Contact Dan Sewell at http://www.twitter.com/dansewell