How Did 17-Year-Old Trezur Williams Die in a Crash Near Dublin, California?

What happened

Just after noon on Friday, 25 September 2026, a northbound 2004 Honda Civic collided with a southbound 2014 Freightliner Cascadia tractor pulling two end-dump trailers on Mountain House Road, north of West Grant Line Road, in unincorporated Alameda County, California, near the San Joaquin County border.

• A 17-year-old passenger in the Honda, Trezur Leighane Destyne Williams of Tracy, was ejected from the car and died at the scene.
• The California Highway Patrol says both drivers remained at the scene and are cooperating with the investigation, and alcohol is not believed to have been a factor.
• Investigators described a broadside collision in the southbound lane; the Honda sustained catastrophic damage and the reason it crossed lanes remains unknown.

A community mourns

The Alameda County Coroner's Bureau identified the victim as Williams, a senior at Mountain House High School. A candlelight vigil was held in her honour four days after the crash, where friends and classmates remembered her as a caring and popular teenager. Mountain House High principal Adam Auerbach told the school community that the loss had deeply affected students, staff and families.

The witness appeal

The CHP's Dublin office has asked anyone with information to come forward to help piece together what happened.

• Officer Tyler Hahn said no new witnesses or information had come in, noting the crash happened at a time and on a stretch of road with no homes and very little traffic.
• Anyone who saw the collision can contact CHP-Dublin on (925) 828-0466 and ask for Officer Hartman or Officer Purl.
• The circumstances of the crash remain under active investigation.

Frequently asked questions

Where did the crash happen?

On Mountain House Road, north of West Grant Line Road, in unincorporated Alameda County, California, near the border with San Joaquin County.

When did it happen?

Just after noon on Friday, 25 September 2026.

Who was killed?

Trezur Leighane Destyne Williams, 17, of Tracy, a senior at Mountain House High School.

What vehicles were involved?

A northbound 2004 Honda Civic and a southbound 2014 Freightliner Cascadia tractor pulling two end-dump trailers.

Who should witnesses contact?

The CHP's Dublin office on (925) 828-0466, asking for Officer Hartman or Officer Purl.