# How do I show who caused an accident?

Canonical: https://californiapersonalinjurylaws.com/guides/prove-fault/

Reviewed by Andrew (Andy) R. Gillin; publisher reported approval on 2026-11-04. Original review date was not supplied.

## Short answer

You need proof of what happened and who failed to use care. You also need to show how that failure caused your injury.

## Hypothetical example

A shop’s camera shows a driver turning into a bike lane. The video helps show what each person did.

## How the rule works

Fault and injury are separate parts of the claim. A video may show an unsafe turn. Care records may help show the harm that followed. You usually need proof of both.

## What can change the answer

One photo or report may not tell the whole story. Some records may not be allowed in court. Review the proof as a whole.

## A useful next step

Save photos, witness names, and care records. Ask for video to be kept before it is erased.

## Court decisions behind this answer

### Mitchell v. Gonzales (1991)

54 Cal.3d 1041, pp. 1049–1053. The court favored a substantial-factor instruction for cause in fact over a confusing older instruction.

Limit: Proof of a careless act alone is not enough. The claimed harm must still be linked to that act.

Source: https://law.justia.com/cases/california/supreme-court/3d/54/1041.html

## Sources

- [California Civil Code § 1714 — Responsibility for harm](https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=CIV&sectionNum=1714.)
- [CACI No. 430 — Causation: substantial factor (2026 edition)](https://courts.ca.gov/system/files/file/judicial_council_of_california_civil_jury_instructions_2026.pdf)
- [Mitchell v. Gonzales (1991) 54 Cal.3d 1041](https://law.justia.com/cases/california/supreme-court/3d/54/1041.html)

General information, not legal advice.