A sideshow took over westbound I-80 before Treasure Island around 3 a.m.
The CHP tells us about 100 cars took part in the sideshow.
INTERACTIVE: Take a look at the ABC7 Neighborhood Safety Tracker
Crowds gathered and watched, some setting off fireworks.
Witnesses say the activity lasted about 20 minutes.
Police in Oakland are increasing patrols on the weekends to try to deter sideshows. OPD says drivers caught participating can have their cars towed and held for a month.