BOSTON -- State police and the Massachusetts Highway Department are investigating another incident involving an exposed manhole cover.

Two cars hit an open manhole while driving on Interstate 93 near Milton overnight.

One car lost control and hit the median, and the other got sidelined by two flat tires. No one was hurt.

Massachusetts Highway Department workers were called to the scene. They replaced the cover and checked the area for other potential problems.

It happened near the location of another incident involving a manhole on Monday.

A bus traveling along I-93 hit a manhole, and the cover was found wedged underneath when it stopped a short time later.

The incident follows a serious accident last week, when a storm grate flew into a car's windshield, seriously injuring the driver.