California Highway Patrol dispatch logs, 911 call recordings and transcripts, and roadside assistance company records (AAA, insurance-affiliated towing services, and similar providers) each maintain time-stamped records of when a call was received, when a unit was dispatched, and when a unit arrived on scene. These records should be requested immediately after a disabled vehicle collision, through both formal Public Records Act requests to CHP and, where a private roadside assistance company was involved, targeted discovery or subpoena once litigation is underway. Retention periods for call recordings in particular can be short, making prompt preservation letters essential. CHP also maintains internal performance goals for response times that vary by call priority, location, and time of day, and a documented response that falls meaningfully outside those benchmarks can support an argument that the delay itself was unreasonable.