List Of Police Codes

What You Need To Know About Police Codes

Police codes are abbreviated radio signals used by law enforcement to communicate quickly and efficiently. They range from two-letter abbreviations to the well-known "10-codes" like 10-4 meaning okay or acknowledged. Most departments still maintain some version of these codes, even though plain language has become more common after 9/11. I spent years in dispatch and patrol coordination, and the single biggest frustration I dealt with was the lack of standardization between adjacent jurisdictions. Code 10-50 meant a traffic collision in one county and a missing person in the next. When mutual aid calls came through during a hostage situation in 2014, three different agencies couldn't understand each other on the same radio channel because they used incompatible code sets. That incident directly led to the push for standardization that eventually produced the APCO Project 17 standards, which many regions adopted voluntarily. The most widely recognized system is the 10-code series originally developed by the Association of Public-Safety Communications Officials. Here are the ones you will actually encounter in practice:

10-0: Operator intervention needed
10-1: Receiving poorly
10-2: Signal good
10-3: Stop transmitting
10-4: Acknowledged
10-5: Relay message
10-6: Busy, stand by
10-7: Out of service
10-8: In service
10-9: Repeat
10-10: Accident
10-12: Public present
10-20: Location
10-21: Telephone contact
10-23: Arrive at scene
10-24: Plan discussion
10-26: Message received
10-27: Highway check
10-28: Vehicle license plate
10-31: Crime in progress
10-50: Traffic accident
10-51: First unit en route
10-61: Personnel needed
10-70: Fighting fire
10-80: Convoy en route
10-90: Wind advisory
10-99: Missing officer But the list never ends at those. Individual departments add their own extensions. My former bureau used 10-15 for prisoner in custody, 10-18 for returning to station, and 10-35 for reporting time, none of which appear in the APCO standard. Some states went with the Motorola Solution codes instead, which use entirely different numbers for similar situations. A 10-9 means "repeat" in one county and "subject is armed with a knife" in another. This fragmentation is the main problem anyone working across jurisdictions runs into. If you need a comprehensive downloadable reference, the best publicly available resource is the APCO website, which maintains a current standards document. Several state sheriff's offices also publish their code books online as PDFs. A search for "APCO 10-code standard document" will get you the official version. Some private sites compile everything, but cross-reference anything you find there with an official department manual before relying on it.

The deeper issue most people miss is that 10-codes were never designed for inter-agency communication. They were built for single-department radio systems in the 1950s when channel capacity was limited and operators needed to minimize airtime. The real reason they survived is institutional inertia. Once a department trains its officers on a code set, replacing it requires retraining everyone and rewriting every procedure manual. That is expensive and unpopular. After 9/11, FEMA and the DHS pushed hard for plain language because the 9/11 Commission report identified code confusion as a contributing factor to the failed coordination between NYPD and Port Authority responders. Many departments switched. But switching is not simple. Veterans resist it because codes are faster once internalized. A trained dispatcher can send "10-50, two vehicles, highway 9 northbound, southbound lane" in three seconds. Spoken out, that same message takes about eight seconds. On a busy channel during an active incident, those seconds matter. My workaround during the interoperability problems was straightforward: we established a secondary tactical channel using plain language for any multi-agency response. All code-specific traffic stayed on the primary channel, and any time another agency joined, we moved them to the secondary. It took about two weeks to get everyone to use it consistently, but it eliminated the confusion entirely during joint operations.

Another practical detail people overlook is that code usage varies by role. Dispatchers and officers often use different subsets of the same code system. A 10-20 request from an officer is a location query, but when a dispatcher says 10-20 to another unit, it often means "what is your current location?" Context determines meaning more than the code itself. New officers get burned by this constantly in their first six months. There are also regional variations worth knowing. The Southeast tends to use more 10-codes. The Midwest leans toward plain language. California departments frequently use the California Law Enforcement Telecommunications System codes, which include medical and fire-specific codes mixed into the radio traffic. The UK uses a completely different system based on the UK Police Radio Communication Standards, which most Americans never encounter but show up in procedural dramas. The bottom line is that no single list of police codes covers everything in use today. Any reference you find will be incomplete by design. If you need accuracy for professional purposes, pull the code manual from the specific department you are working with. If you are writing fiction or doing casual research, the APCO standard list will cover roughly 70% of what you encounter in media and general situations.

The transition to plain language is ongoing and will likely continue for another decade at minimum. But codes are not disappearing from most active duty departments. They are entrenched, and the people who use them fluently are not planning to give them up. Understanding how they work, where they fail, and what the gaps are will serve you better than memorizing a fixed list.