RELATED: Live traffic maps show back up from SF bus crash
Of the victims, four suffered serious injuries, nine suffered moderate injuries and 16 suffered minor injuries, San Francisco Fire Department officials said.
19 of those victims have now been released from the hospital, all victims are expected to make full recoveries.
The California Highway Patrol first reported the incident at 8:06 p.m. on southbound Highway 101 at the Cesar Chavez Street off-ramp.
The bus started wavering back and forth, hit the center median and bounced back across four lanes of traffic, crashing on the other side.
Most passengers were able to get out through broken windows or escape hatches. Two passengers had to be extracted by firefighters.
The overturned bus blocked southbound lanes and a Sig-alert was issued, closing all but one southbound lane.
The cause of the crash is still under investigation. Fire officials say the driver was not impaired.
"The driver, commend the driver. He had some injuries and he stayed on the scene and he was the very last person to get onto one of the ambulances. He wanted to make sure everybody was accounted for. Everybody's needs were taken care of and again he stayed here until everything was done and he was the last person to get onto a bus," said Lt. Jonathan Baxter, with the San Francisco Fire Department.
The bus is owned by Charter Brothers. It's a family-owned company that advertises more than 20-years of experience.
The company conducts charters for corporate events, schools, weddings and field trips.
The company's website says its buses can transport up to 56 passengers.
The crash was cleared around 2 a.m. this morning, according to the CHP.
Bay City News contributed to this report.
Here's the latest information on the bus crash at Highway 101 and Cesar Chavez. @LarryBeil reports from the ABC7 Newsroom: https://t.co/ciIly6fdpA . pic.twitter.com/1SzzSjt7er
— ABC7 News (@abc7newsbayarea) December 9, 2017
Just arrived at SF General: SFFD mass casualty transport. @abc7newsbayarea @DionLimTV pic.twitter.com/x8XfzWhqD7
— Katie Marzullo (@KatieABC7) December 9, 2017
Mechanical experts on scene now trying to figure out the cause of the crash. Driver was not impaired. #abc7now pic.twitter.com/YaWRPzxpRx
— Dion Lim (@DionLimTV) December 9, 2017
OVERTURNED BUS: 101 SB at Cesar Chavez. 2-4 lanes blocked. Reports of 4-6 with major injuries. Major backups. #ABC7now pic.twitter.com/MWkSjrjEYB
— Dion Lim (@DionLimTV) December 9, 2017
From @CHPSanFrancisco: Bus hit center median wall ricocheted & crashed on the right. Driver is a male. 29 injured, 4 seriously. #ABC7now pic.twitter.com/E7pwGMoWNr
— Dion Lim (@DionLimTV) December 9, 2017
#BREAKING: 8 people from bus crash at SF General. 5 women, 3 men. Conditions unknown but none critical. @abc7newsbayarea @DionLimTV pic.twitter.com/PuWAr41hKn
— Katie Marzullo (@KatieABC7) December 9, 2017
Update from SF General: 23 patients here. 22 in fair condition. 1 in serious condition. @abc7newsbayarea @DionLimTV pic.twitter.com/heCxS8LCHO
— Katie Marzullo (@KatieABC7) December 9, 2017