Sedan separated by tow operators from big rig that smashed into it after losing brakes. #Hwy1 at River St. #SantaCruz - 20 vehicle pileup caused 11 injuries; 3 critical. Rig loaded w/clay. Drivers had alerted #CHP rig’s brakes were smoking. Hwy 1 NB still closed. #abc7now pic.twitter.com/psVNKF1CsW — David Louie (@abc7david) November 13, 2018

EMBED >More News Videos A fiery crash involving a big rig and 20 passenger vehicles created major gridlock in Santa Cruz for most of the day.

20 car pileup has NB Hwy 1 closed until mid afternoon after big rig lost brakes and rear ended this sedan. 11 injuries; 3 critical. At Hwy 1 & River St. #santacruz #abc7now pic.twitter.com/BeEeScWYLm — David Louie (@abc7david) November 13, 2018

Big rig accident involving about 10 vehicles has NB 1 closed at River St. #SantaCruz SB 1 traffic also impacted. Rig cab caught fire. Extent of injuries unknown. #abc7now pic.twitter.com/AXZE1tHP5P — David Louie (@abc7david) November 13, 2018

SANTA CRUZ, Calif. (KGO) -- A fiery crash involving a big rig and 20 passenger vehicles created major gridlock in Santa Cruz for most of the day. The CHP says the cause may have been faulty brakes.Drivers of 20 vehicles were stopped at a traffic light right as a tractor-trailer barreled toward them that the CHP said had lost its brakes.The tractor smashed into a small sedan, setting both on fire. The driver of the passenger car was one of three crash victims who suffered critical injuries. The big rig driver received moderate injuries.Aptos resident Mary Sierra, who was on her way to work, said it all happened so quickly."So quickly like I didn't even know what happened to tell you the truth," she said. "I was kind of in shock, and somebody had to come to the car and tell me to get out because it was smoking. So she helped me get out through the passenger side."The tractor was pulling a heavy load of clay. The cab door identified the company as JVillas Trucking, based in San Jose, a firm with a large number of safety violations in the past two years, according to U.S. Department of Transportation. Its trucks have been pulled out of service 16 times after 21 inspections-- a rate of 76 percent versus the national average of about 21 percent.Drivers had reported to CHP that they saw the rig spewing smoke and fire just before the crash."Just minutes prior, witnesses had called in to say that they had observed the big rig with its wheels smoking and fire, so it's presumably the brakes going out," said CHP Santa Cruz Sgt. Grant Boles.CHP estimates the big rig was moving at about 30 to 40 miles an hour when it hit the guardrail, a barrier and then caused a series of ping-pong collisions. Some children on a field trip were not injured.The northbound lanes of Highway 1 were re-opened at mid-afternoon. The six-hour closure was due to an on-site inspection of the big rig, removal of the wrecked vehicles, cleanup of spilled diesel and gasoline, and a check of possible damage to the pavement caused by the crash fire.