OKLAHOMA CITY -- A bridge overpass above an Oklahoma City highway collapsed Thursday afternoon, but no injuries were reported.

CBS affiliate KWTV reported emergency crews were on the scene after the northbound side of the N. May Avenue bridge collapsed onto Northwest Expressway. A truck was trapped under the debris, but the driver of the vehicle is okay, police told the station.

It appeared that a flatbed semi hauling some sort of heavy equipment too tall for the bridge passed under and tore the northbound lanes down.

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Authorities shut down both May Avenue and Northwest Expressway in both directions in the area while crews cleared the scene.

A spokesperson for the Oklahoma City fire department told KWTV officials expect it to be a long cleanup and they were not sure when the roads will be reopened. The spokesperson also said the bridge belonged to the city and not the Oklahoma Department of Transportation.

The driver of the semi told investigators he had already passed under the bridge heading eastbound and assumed he would be able to fit when he returned on the westbound side. There is a height difference of four inches from the eastbound lanes and westbound lanes -- 14' 8" to 14' 4" respectively.

Engineers were evaluating the damage to the bridge and an estimate on the time needed for repairs would not be available until the evaluation is complete, a report stated.