California Highway Patrol CAD: Complete 2026 Guide To Reading Live CHP Traffic Incident Logs

Disambiguation Note: This guide covers the California Highway Patrol Computer-Aided Dispatch (CHP CAD) public incident tracking system, not Combined Heat and Power computer-aided engineering (CHP CAD) or currency exchange tracking.

Computer-Aided Dispatch (CAD) operated by the California Highway Patrol serves as the digital backbone for real-time traffic incident management, emergency resource coordination, and public road safety reporting across California's 39,000 miles of highway. Originally engineered as an internal coordination system for telecommunicators and patrol officers, the public-facing CHP CAD media log has become one of the most critical situational awareness tools for commuters, commercial freight dispatchers, newsrooms, and emergency personnel.

Operating 24 hours a day, 365 days a year, the CHP CAD system processes hundreds of thousands of entries annually, ranging from minor traffic hazards and disabled vehicles to multi-agency SigAlert events and severe collisions. Understanding how to query, interpret, and cross-reference the system in 2026 requires practical knowledge of state dispatch center jurisdictions, police communication codes, and technical system behaviors.

What Is the California Highway Patrol Computer-Aided Dispatch System?

The California Highway Patrol CAD system is an automated, real-time public safety communications infrastructure. When a 911 call originates from a California freeway or an unincorporated county roadway, the call routes directly to one of the CHP's regional dispatch communications centers. Dispatchers enter caller details, vehicle descriptions, milepost markers, and situational developments directly into the internal CAD database.

A filtered subset of this data is mirrored instantly to the public CHP CAD web portal (cad.chp.ca.gov) and distributed via live XML and data feeds to enterprise transportation software, including Caltrans QuickMap and commercial mapping applications.

The public platform omits sensitive law enforcement information—such as suspect personal identification, officer tactical movements, suicide attempts, domestic incidents, and juvenile records—while preserving immediate, operational roadway data:

• Location Precision: Incident freeway names, directional lanes (e.g., NB, SB, EB, WB), nearest off-ramps, and state route postmiles.
• Timestamped Activity Logs: Rolling dispatch operational updates detailing when tow services are rolling, ambulances arrive, lanes close, or evidence is cleared.
• Unit Identifiers: Specific highway patrol units, Caltrans road maintenance trucks, and partner emergency response vehicles assigned to the scene.

Regional CHP Dispatch Communication Centers

The state of California divides CHP CAD data operations into distinct jurisdictional communications centers across eight operational field divisions. Understanding which center manages a specific highway corridor is essential for locating incident reports quickly.

Decoding Common CHP CAD Log Codes and Jargon

The incident log entries on the CHP CAD portal rely heavily on standardized California Penal Codes, California Vehicle Codes (CVC), and classical 10-series/11-series police radio brevity codes. Deciphering these terms provides immediate clarity regarding road conditions.

Critical Collision and Incident Classifications

• 11-82: Property damage collision only. No personal injuries reported; typically cleared quickly unless vehicles are blocking operational lanes.
• 11-83: Traffic collision with unknown injury status. Dispatched automatically with paramedic and fire staging until the first on-scene unit confirms patient conditions.
• 11-79: Traffic collision with ambulance responding. Indicates confirmed injuries requiring medical evacuation or triage.
• 11-44: Fatality at scene. CAD entries displaying this code or transitioning to coroner dispatch will experience extended roadway closures for Major Accident Investigation Teams (MAIT).
• 20001 CVC: Hit-and-run traffic collision resulting in injury or death.
• 20002 CVC: Hit-and-run collision causing property damage only.
• 23152 CVC: Driving under the influence of alcohol or drugs. CAD logs frequently note these as suspected impaired drivers prior to an enforcement stop.

Operational Dispatch Action Phrases

• SigAlert: An official alert issued by CHP indicating that an unplanned incident has blocked two or more traffic lanes for 30 minutes or longer.
• 10-39: Message or notification delivered. For example, "10-39 Caltrans" means Caltrans road maintenance has been notified to provide cones, message boards, or lane closures.
• 10-97: Arrived at scene. Confirms that a patrol cruiser, fire engine, or utility vehicle is physically on location.
• 10-98: Finished assignment. The unit has concluded operational duties and is departing the incident.
• TOW / ROTATION: Commercial rotational towing company summoned to impound, winch, or remove disabled vehicles.
• CLOSURE / HARD CLOSURE: Complete shutdown of the freeway or specific lanes. A "soft closure" allows traffic to trickle through past emergency vehicles, whereas a "hard closure" diverts all traffic to surface streets.

Step-by-Step: How to Read and Navigate the Public CHP CAD Log

Accessing and interpreting real-time roadway intelligence via the desktop or mobile interface follows a clear diagnostic path.

1. Access the Central Interface: Navigate to the official California Highway Patrol CAD public website.
2. Select the Communications Center: Use the dropdown menu to select the dispatch center governing the destination or travel path (for instance, select Golden Gate if traveling across the Bay Area bridges or Los Angeles if navigating the I-5/I-405 corridors).
3. Scan the Incident List: The landing dashboard organizes active incidents in reverse chronological order based on the latest update. Focus on the ID, Time, Type, and Location columns.
4. Open the Detail Modal: Select the specific incident numeric ID link to reveal the timestamped operational feed.
5. Evaluate the Timeline Updates: Read from top to bottom. The top entry represents the initial 911 dispatch notification; the bottom entry represents the most recent operational report entered by the communications operator.

Reading Operational Timelines

Always cross-examine the timestamps between updates. Initial caller claims frequently contradict verified field reports. Callers often report an overturned vehicle or serious injury that arriving units determine to be minor fender benders, or vice versa. The presence of codes like 10-97 alongside a revised code provides the single most reliable picture of ground reality.

CHP CAD vs. Alternative Real-Time Roadway Systems

Selecting the proper intelligence source depends on your operational requirements. The following comparison illustrates how official CAD data interfaces with alternate navigation tools.

Technical Specifications and API Automation

For developers, transportation managers, and data analysts, scraping or retrieving CAD logs requires compliance with state system parameters. The California Highway Patrol provides filtered XML feeds used primarily by authorized transit groups, emergency management divisions, and software aggregators.

Data Flow Specifications

• Data Format: Public streams utilize standard RESTful XML and JSON structures that parse location coordinates, incident type codes, communication center tags, and operational logs.
• Geocoding Attributes: Modern CAD entries automatically assign approximate latitude and longitude coordinates derived from state route postmile indices and cell phone tower triangular data.
• Rate Limits: Automated programmatic calls made against the standard public web interface are subject to state server firewall throttling. Third-party commercial platforms typically ingest structured data through authorized syndication feeds or the Caltrans Automated Traffic Management System (ATMS).

Common System Failure Modes and Diagnostic Remedies

• Session Timeout / White Screen: During extreme weather events (such as atmospheric rivers or major winter storms over Donner Pass), state web servers experience high volume. Clear browser caching or shift queries directly to the text-only mirror version maintained on mobile state infrastructure.
• Disappearing Incidents: When an incident disappears abruptly from the public CAD board, it typically indicates one of three outcomes: the incident was canceled (false alarm), fully cleared by the tow provider and reopened to traffic, or transitioned into an active criminal or tactical operation, which automatically revokes public feed permissions.

Frequently Asked Questions

What does the CHP CAD log show to the public?

The public CHP CAD log displays real-time, non-sensitive operational details regarding traffic collisions, disabled vehicles, highway debris, livestock on roadways, and lane closures. It details when emergency units are dispatched, when tow services arrive, and specific lane clearance stages across California highways.

While it delivers rich logistical data, it deliberately omits personal medical information, driver identities, tactical police movements, and sensitive criminal investigations to protect public privacy and operational safety.

Why do some incidents disappear from the CHP CAD board?

Incidents disappear from the public log when patrol units clear the scene, traffic lanes fully reopen, or the incident changes to a restricted status.

Incidents involving severe criminal actions, fatalities under formal investigation, or tactical situations are moved off the public feed to prevent traffic rubbernecking and safeguard investigative integrity.

What is the difference between CHP CAD and Caltrans QuickMap?

CHP CAD is the primary text dispatch log generated directly by 911 telecommunicators handling incidents in real time, whereas Caltrans QuickMap is an integrated geographic map platform.

QuickMap ingests CHP CAD incident data and overlays it alongside physical Caltrans equipment: live highway traffic cameras, lane closure permits, electronic message boards, and pavement-embedded speed loop sensors.

What does a SigAlert mean on a CHP CAD entry?

A SigAlert indicates that an unplanned incident has blocked two or more travel lanes for an anticipated duration of at least 30 minutes.

Named after early radio pioneer Loyd Sigmon, the issuance of a SigAlert triggers automated notifications to news broadcasts, navigation engines, and regional traffic management centers to divert approaching traffic.

How accurate are the location postmiles on CAD entries?

Location postmiles are generally accurate within several hundred feet, as CHP units and state road workers rely on physical white postmile markers placed along highway shoulders.

However, the initial location on a fresh CAD log relies on consumer 911 estimates, which can misidentify directional lanes (e.g., reporting an incident on Northbound US-101 that actually occurred on Southbound US-101) until the first officer arrives at the scene and confirms the postmile.

Optimize your California fleet operations, emergency logistics, and regional commuting strategy by monitoring live dispatch events directly through official public safety feeds and regional traffic management interfaces.