Police break up sideshows on the Bay Bridge, Brentwood

Bay Area police were busy this weekend breaking up more dangerous sideshows.

One broke out on Friday night on the Bay Bridge. 

The Instagram account, Bay Area Alert, posted video of several cars spinning donuts across the eastbound lanes of the bridge.

As traffic backed up, people stood around watching.

The California Highway Patrol has not yet said if arrests were made or citations issued.

Then, in Brentwood, cars drove recklessly on Sand Creek Road near Highway 4 early Sunday.

Witnesses told KTVU this illegal sideshow continued for 90 minutes before it was broken up by the Contra Costa County Sheriff's Office.

There was no immediate word on arrests.