CHP collision report codes

A California collision report records most of what it captures in coded fields rather than sentences. Each field has a fixed list of options, and the officer marks one. Here is what the main ones mean.

It is general information, not legal advice.

Primary collision factor

The officer's identification of the single most important cause of the crash. It is recorded as a category — for example a Vehicle Code violation by one party, another factor, or unknown — and, when it is a violation, the specific Vehicle Code section and the party responsible. Common sections include unsafe speed, following too closely, improper turning, failure to yield at a left turn, red-light and stop-sign violations, wrong side of the road, unsafe lane change, pedestrian right-of-way, and driving under the influence. This field is the report's nearest thing to a fault finding.

Movement preceding collision

What each party was doing just before impact — proceeding straight, stopped, making a left or right turn, changing lanes, merging, backing, passing, entering or leaving a parked position, slowing or stopping. The combination of the two parties' movements often tells the story: "stopped" versus "proceeding straight" points one way; "making left turn" versus "proceeding straight" points another.

Type of collision

The geometry of the crash — head-on, rear-end, broadside (T-bone), sideswipe, hit object, overturned, pedestrian, or other. This should be consistent with the damage and the diagram.

Party sobriety and physical condition

Codes for whether the officer believed each party had been drinking or using drugs, whether impairment was suspected, and whether a test was given. Also fields for whether the party appeared fatigued, ill, or otherwise impaired.

Conditions

• Weather — clear, cloudy, raining, fog, wind, snow.
• Lighting — daylight, dusk or dawn, dark with street lights, dark without.
• Roadway surface — dry, wet, snowy or icy, slippery from other material.
• Roadway condition — normal, or a defect, construction, obstruction, or loose material.
• Road type and traffic control — the type of intersection or roadway and whether a signal, sign, or markings were present and functioning.

Other coded fields

• Pedestrian action — in a crosswalk at an intersection, in a crosswalk not at an intersection, crossing not in a crosswalk, in the road, on a sidewalk.
• Safety equipment — seat belt, car seat, helmet use.
• Vehicle type and, for a commercial vehicle, carrier and hazardous-materials fields.
• Injury level per party and passenger on a standard scale.

What the codes are and are not

The coded fields are the officer's scene assessment, made quickly and sometimes before hearing every account. They drive how an adjuster reads the report and they feed state statistics, but they do not decide fault or the value of a claim. Reading the report as a whole is covered on how to read a California traffic collision report.

Common questions

Why is the report full of codes instead of sentences?

The collision report is a standardized statewide form. The coded fields let every agency record a crash the same way and feed the state crash database. Each box maps to a defined list of options.

What does the Vehicle Code section next to the primary collision factor mean?

It is the specific traffic law the officer believes was violated and that mainly caused the crash — for example an unsafe-speed or failure-to-yield section. It signals the officer's view of fault.

What is SWITRS?

The Statewide Integrated Traffic Records System — the state database that collision reports feed. The coded fields on the report are what populate it.

A box seems wrong. Does that matter?

It can. A coded field that misstates a movement, a condition, or sobriety can shape how an adjuster reads the whole report. Factual coding errors can be raised with the investigating agency; how they affect a claim is a separate question.