The Comprehensive Guide To California Highway Patrol Radio Codes: 2026 Official Reference
The California Highway Patrol (CHP) maintains one of the most complex and high-volume public safety communication networks in the United States. In 2026, as the agency continues its transition toward fully integrated digital P25 Phase II systems and advanced LTE-based FirstNet integration, understanding the verbal shorthand used by dispatchers and officers is essential for interoperability and public transparency. This guide focuses exclusively on the radio codes used by the California Highway Patrol (State Police functions) and does not cover local municipal police or county sheriff codes unless they overlap within the California Law Enforcement Telecommunications System (CLETS) standards.
For those monitoring scanners or studying for a career in California law enforcement, the terminology consists of two primary frameworks: the standard "10-Codes" and the California-specific "11-Codes." While many agencies have moved toward "plain talk" to comply with NIMS (National Incident Management System) standards, the CHP retains a deep reliance on these codes to maintain brevity and clarity across the state’s vast and often congested radio frequencies.
The Architecture of CHP Communications in 2026
By 2026, the CHP has modernized its radio infrastructure to ensure seamless communication across California's diverse topography. While the traditional "Low Band" (42 MHz) systems are still utilized for their exceptional range in mountainous and rural corridors, the majority of urban operations have migrated to the 700/800 MHz bands.
Communication is structured around specific "Dispatch Centers" (CDCs) that manage various "Areas." When an officer keys the mic, they are not just speaking to a dispatcher; they are interacting with a sophisticated data-linked ecosystem. The use of codes serves to minimize "air time," which is a critical safety factor when hundreds of units are sharing a single repeater.
The Significance of 11-Codes
Unique to California, the 11-series codes are the backbone of traffic enforcement and highway safety. While 10-4 is understood globally, 11-99 is a phrase that carries immediate, life-altering weight within the state. These codes are designed to provide specific status updates regarding traffic collisions, disabled vehicles, and officer safety transitions that 10-codes do not adequately cover.
Master Reference: CHP 11-Codes and 10-Codes for 2026
The following table provides the most current definitions for the codes utilized across California Highway Patrol frequencies. These remain the standard for 2026 operational procedures.
| Code | Type | Meaning and Operational Context |
|---|---|---|
| 10-1 | 10-Code | Poor reception; signal is weak or unreadable. |
| 10-2 | 10-Code | Good reception; signal is clear. |
| 10-4 | 10-Code | Acknowledgement; message received and understood. |
| 10-6 | 10-Code | Busy, stand by unless urgent. |
| 10-7 | 10-Code | Out of service; officer is off-duty or at a location where they cannot respond. |
| 10-8 | 10-Code | In service; available for assignment and patrolling. |
| 10-10 | 10-Code | Off-duty; end of shift. |
| 10-15 | 10-Code | Prisoner in custody; used when an arrest has been made. |
| 10-19 | 10-Code | Return to the office or station. |
| 10-20 | 10-Code | Location; used to ask for or provide current coordinates. |
| 10-21 | 10-Code | Telephone the station or a specific individual. |
| 10-22 | 10-Code | Disregard previous transmission or assignment. |
| 10-23 | 10-Code | Arrived at the scene of the assignment. |
| 10-27 | 10-Code | Request for Driver's License information. |
| 10-28 | 10-Code | Request for Vehicle Registration information. |
| 10-29 | 10-Code | Check for wants or warrants on a person or vehicle. |
| 10-31 | 10-Code | Crime in progress. |
| 10-36 | 10-Code | Correct time. |
| 10-39 | 10-Code | Message or item has been delivered/contacted. |
| 10-97 | 10-Code | Arrived at the scene (often used interchangeably with 10-23). |
| 10-98 | 10-Code | Assignment completed; available for next call. |
| 11-10 | 11-Code | Take a report (Administrative or field report). |
| 11-24 | 11-Code | Abandoned vehicle (often found on highway shoulders). |
| 11-25 | 11-Code | Traffic hazard; debris or object in the roadway. |
| 11-26 | 11-Code | Disabled vehicle; motorist needs assistance. |
| 11-41 | 11-Code | Ambulance required immediately. |
| 11-44 | 11-Code | Fatality; Coroner required at the scene. |
| 11-48 | 11-Code | Request for transportation (usually for a citizen). |
| 11-79 | 11-Code | Accident involving an ambulance (High priority). |
| 11-80 | 11-Code | Accident with serious major injuries. |
| 11-81 | 11-Code | Accident with minor injuries. |
| 11-82 | 11-Code | Accident involving property damage only (no injuries). |
| 11-83 | 11-Code | Accident details unknown (initial report). |
| 11-84 | 11-Code | Traffic control required; officer directing traffic. |
| 11-85 | 11-Code | Tow truck required (specify flatbed or heavy-duty). |
| 11-98 | 11-Code | Meet an officer at a specific location. |
| 11-99 | 11-Code | OFFICER NEEDS HELP. Emergency priority; all units respond. |
California Highway Patrol Address - TZXUM
Emergency Response Status and Clearance Codes
In addition to the alphanumeric codes, the CHP utilizes "Code" designations to indicate the urgency of a response and the status of a scene. In 2026, these are strictly enforced to ensure public safety and officer accountability.
Code 1: Standard Response The officer responds at their convenience or when available. No emergency lights or sirens are used. This is typically for non-urgent administrative tasks or follow-ups.
Code 2: Urgent Response The officer responds immediately to the call. No emergency lights or sirens are used, and the officer must obey all traffic laws. This is for incidents that are pressing but do not constitute an active life-threat.
Code 3: Emergency Response This is a high-priority emergency response using "blue and red" lights and sirens. Under California Vehicle Code Section 21055, this allows the officer to bypass certain traffic regulations while exercising due caution.
Code 4: No Further Assistance Needed This is broadcast when a scene is under control. It signals to other responding units that they can clear the call and return to their beats.
Unit Identifiers and The California Phonetic Alphabet
To understand a transmission, you must identify who is speaking. CHP unit identifiers are typically three-part designations:
- The Area Number: Represents the specific CHP office (e.g., 23 is the West Los Angeles Area).
- The Unit Type: A letter designating the type of unit (e.g., "S" for Sergeant, "A" for Air Unit).
- The Unit Number: The specific beat or car number.
Example: "23-S-1" would be a Sergeant from the West Los Angeles Area.
The 2026 Phonetic Alphabet Standard
While the military uses the NATO phonetic alphabet (Alpha, Bravo, Charlie), the CHP and most California law enforcement agencies use a traditional California-specific phonetic alphabet to ensure letters are not confused during poor signal conditions.
- A: Adam
- B: Boy
- C: Charles
- D: David
- E: Edward
- F: Frank
- G: George
- H: Henry
- I: Ida
- J: John
- K: King
- L: Lincoln
- M: Mary
- N: Nora
- O: Ocean
- P: Paul
- Q: Queen
- R: Robert
- S: Sam
- T: Tom
- U: Union
- V: Victor
- W: William
- X: X-ray
- Y: Yellow
- Z: Zebra
Technological Evolution: Monitoring CHP in 2026
The landscape for scanner enthusiasts and journalists has shifted significantly in 2026. If you are attempting to monitor CHP radio codes, you must be aware of the hardware requirements and legal constraints currently in place.
P25 Phase II and Trunking
The CHP has largely completed its migration to P25 Phase II digital systems in major metropolitan areas like the San Francisco Bay Area, Los Angeles, and San Diego. To hear these transmissions, a digital trunking scanner capable of TDMA (Time Division Multiple Access) decoding is required. Analog scanners will only pick up "white noise" or encrypted data bursts on these frequencies.
Encryption Realities
In compliance with California Department of Justice (DOJ) mandates regarding the protection of Personally Identifiable Information (PII) and Criminal Justice Information (CJI), the CHP has implemented encryption on many of its "Tactical" and "Inquiry" channels. While main dispatch channels usually remain "in the clear" for public transparency, detailed 10-29 (warrant) checks and sensitive tactical operations are now encrypted and cannot be monitored by the public.
Legal Considerations
Under California Penal Code Section 636.5, it is a misdemeanor to intercept public safety radio communications for the purpose of assisting in the commission of a crime or to avoid discovery by law enforcement. Furthermore, using a scanner in a motor vehicle to facilitate a crime is a serious offense. In 2026, mobile scanner apps are widely available, but users should remain aware that these streams often have a 30-to-60-second delay compared to real-time radio traffic.
Comparison: CHP Codes vs. Standard LAPD/California Codes
While there is significant overlap, the CHP uses "11-codes" more frequently than municipal agencies.
| Category | California Highway Patrol (CHP) | Standard Municipal Police (LAPD Style) |
|---|---|---|
| Officer Needs Help | 11-99 (Absolute Priority) | Code 3 / 999 |
| Accident | 11-80, 81, 82, 83 (Detailed) | 10-34 or "Traffic Collision" |
| Tow Truck | 11-85 | 10-35 or "Requesting Hook" |
| Ambulance | 11-41 | 10-52 or "Rescue" |
Pros and Cons of Radio Code Usage in 2026
Pros
- Efficiency: Codes allow for complex information (like an accident with major injuries and a request for a tow truck) to be conveyed in seconds.
- Discretion: Codes provide a minor layer of privacy against casual eavesdropping in public spaces.
- Standardization: Officers transferring between different CHP areas across the state do not need to relearn local terminology.
Cons
- Training Burden: New recruits must memorize hundreds of codes to reach operational fluency.
- Interoperability Hurdles: During multi-agency disasters (like major wildfires), different agencies using different codes can lead to dangerous confusion. This is why "Plain Language" is mandated for major incidents.
Frequently Asked Questions
What does 11-99 mean on a CHP radio?
11-99 is the most urgent emergency code used by the California Highway Patrol, signifying "Officer Needs Help." When this code is broadcast, it indicates that an officer is in a life-threatening situation, and all available units from all nearby agencies are expected to respond immediately with emergency lights and sirens (Code 3).
Why does the CHP still use 10-codes in 2026?
The CHP continues to use 10-codes and 11-codes because they provide a highly efficient way to communicate on crowded radio frequencies. Despite federal recommendations for plain language, the sheer volume of traffic on CHP dispatch channels makes brevity a safety requirement to ensure airtime is available for emergencies.
Can I listen to CHP radio codes on my smartphone?
Yes, in 2026, various mobile applications stream public safety radio traffic. However, most of these streams are provided by volunteers with scanners and may experience downtime. Additionally, sensitive or tactical transmissions are often encrypted and will not be available on these apps.
What is the difference between a 10-27 and a 10-29?
A 10-27 is a specific request for a driver's license status and history, whereas a 10-29 is a check for "wants and warrants" to see if a person is currently wanted for a crime. Often, an officer will request both (a "27 and 29") during a traffic stop.
How do I know which CHP frequency to monitor?
CHP frequencies are organized by "Color" or "Area" names (e.g., CHP Blue, CHP Granite, CHP Silver). In 2026, you should consult an updated frequency database or the RadioReference database to find the specific P25 talkgroup or frequency assigned to the highway corridor you are interested in.
Is it legal to have a police scanner in my car in California?
Generally, it is legal to possess a scanner in California as long as it is not used to further a crime. However, some local ordinances may restrict their use, and if you are pulled over, having a scanner actively tuned to police frequencies can lead to increased scrutiny from the officer.
Expert Insight: Navigating the 2026 Communications Landscape
As a technical strategist in public safety communications, my advice for those interacting with or monitoring the CHP is to focus on the "11-series" codes first. While 10-codes are common across North America, the 11-codes are the true language of the California highways. In 2026, the integration of AI-assisted dispatching means that these codes are also being parsed by computers to automatically route tow trucks (11-85) and ambulances (11-41), making the accuracy of these verbal codes more important than ever for the speed of emergency response.
Always remember that radio traffic is a professional environment. If you are using a two-way radio on a coordinated frequency (such as a search and rescue volunteer or authorized contractor), adhere strictly to the "Brevity, Clarity, Accuracy" rule. Avoid "cb-slang" and stick to the official 2026 CHP code manual to ensure your message is understood the first time.
