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Model Minimum Uniform Crash Criteria -- 5th Edition


To encourage greater uniformity, the National Highway Traffic Safety Administration (NHTSA) and the Governors Highway Safety Association (GHSA) cooperatively developed a voluntary data collection guideline in 1998. The MMUCC guideline identifies a minimum set of motor vehicle crash data elements and their attributes that States should consider collecting and including in their State crash data system.

Document MMUCC 5th Edition Guideline Download

The MMUCC 5th Edition is the result of an 18-month collaboration between NHTSA, the Federal Highway Administration (FHWA), the Federal Motor Carrier Safety Administration (FMCSA), the National Transportation Safety Board (NTSB), the GHSA, and subject matter experts from State DOTs, local law enforcement, emergency medical services, safety organizations, industry partners, and academia. The traffic records community and general public also contributed through external forums (Federal Register) and at the 2016 Traffic Records Forum.

Changes to MMUCC

Several important changes were made in the 5th edition that provide States more flexibility, enhance data collection efforts and will improve data quality. 

MMUCC no longer defines how data elements should be collected (at scene/linked or derived). States are encouraged to link or derive wherever possible to minimize the impact on law enforcement.

Following State best practices, MMUCC now includes Fatal, Large Vehicles and Hazardous Materials, and Non-Motorist crash data sections; these are only completed if applicable. The Model Minimum changes based on the circumstances instead of a one-size-fits-all approach.

A new type of data element—contained in the Dynamic Data Elements section—is introduced for the first time to capture data on topics that are changing rapidly. Dynamic data elements may change more frequently than each edition (every 5 years).

Twenty Years and Counting


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Data Collectors

Safety Starts with Crash Data

Law enforcement efforts to collect quality crash data is critical to local, regional, State and national safety programs in engineering, enforcement, EMS and education.

It All Starts With You

We get it. You have countless demands on your time and attention, and they only increase each year. Prioritizing your time is part of the job.  

Traffic Records Systems - Hub-and-Spoke

For our part, we’d like to help make the task of completing crash reports as painless as possible, and explain why they – and your role in them – are so critical to EVERYTHING we do. 

Safety Starts with Crash Data. There is almost no safety program, initiative, countermeasure or analysis that can be done without it. Your efforts investigating and reporting crashes form the foundation of all safety programs.

MMUCC 5 Crash Report Form

The MMUCC crash report form visualizes all 115 elements of the 5th Edition, including the new sections for fatal, large vehicles and hazardous materials and non-motorist sections.

Data Managers

Managing Data

The roles of State crash database administrators, managers, and technicians are vitally important to the development and deployment of effective traffic safety countermeasures. A quality crash data system that is timely, accurate, complete, uniform, integrated and accessible, benefits a broad spectrum of data users. Adopting the MMUCC 5th Edition Guideline can help improve the quality of crash data that are essential to improving highway safety.

New Features of MMUCC 5th Edition

Data elements are no longer defined by source (collected at the scene, derived from other data sources or linked to other databases). States are encouraged to link or derive data elements where possible to diminish the impact on law enforcement officers.

Data elements that were previously indicated as linked or derived are now shown in both the table of contents and by the data element name with the link symbol. [[{"fid":"36906","view_mode":"default","fields":{"format":"default","alignment":"","field_file_image_alt_text[und][0][value]":"Image of link"},"type":"media","field_deltas":{"1":{"format":"default","alignment":"","field_file_image_alt_text[und][0][value]":"Image of link"}},"attributes":{"alt":"Image of link","class":"media-element file-default","data-delta":"1"}}]]

The “model minimum” is no longer one-size-fits-all. Most elements reside in the main section of MMUCC and are considered minimum for all crash types. Elements that describe crashes involving fatalities, large vehicles and hazardous materials, and non-motorists are separated into three, new sections. States need only consider these sets of elements “minimum” if applicable to the crash.

This change followed the best practice of many States that already modify their data intake based upon crash type and severity. For other States, data managers should consider crash database protocols that accommodate this process.

Lastly, a new dynamic data elements section was created to house elements that may change more frequently than every five years, due to rapidly evolving technology (e.g. automated vehicle system(s)). 

The guidelines have been reformatted to eliminate multiple “subfields” to collect multiple selections from the same list of attributes. MMUCC 5th Edition denotes the number of selections by stating a single number or a range, where appropriate.

Subfields are used to capture distinct pieces of a single data element. For example, the new “Distracted By” element breaks distraction into two parts – action and source.

Attribute lists have been reordered into alphabetical order to diminish selection bias except for some elements where a specific order makes sense (e.g., keeping construction zone sections in vehicle-travel order).

Following the best practice of States and the FARS database, all defined attributes include an attribute code (or number value).

At the request of many States, “model minimum” edit checks were added to most data elements to provide guidance on the types of checks any crash data system should include minimally. For States that wish to have more extensive edit checks, consult the FARS user’s manual, found in the NHTSA CrashStats library.

Technical Assistance Application Download

The NHTSA Traffic Records Team currently offers two programs to States specifically geared to evaluating and improving a State's crash data system - the Crash Data Improvement Program (CDIP) and MMUCC Mappings.

The CDIP technical assistance program examines the quality of a State’s crash data and provides the State with specific recommendations to improve the quality, management and use of that data to support safety decisions. The program includes a complete MMUCC mapping of the statewide crash database to the 5th Edition. This program is free to the States and made available on a first-come, first-served basis given available funds.

The MMUCC Mapping technical assistance program examines the State's crash database, police crash report, data dictionary and law enforcement instruction manual to determine alignment with MMUCC at the attribute and element level. SMEs follow the updated mapping rules (Mapping to MMUCC 5th Edition, page 125, MMUCC 5th Edition); first published in DOT publication DOT-HS-812-184.

MMUCC 5th Edition Guideline

Data Users

Data-Driven Decisions

Crash Data users are those that reap the benefits from the data collected and stored by State and local governments. For many, it helps effectively target and identify highway safety issues. These users also make decisions for business planning, research, and enforcement efforts.

Safety Starts with Crash Data

Quality, uniform crash data forms the foundation for improved traffic safety through analysis, research, data-driven decisions and implementation.

37461.000 2016 Fatalities (source: FARS)
102.000 2016 Fatalities per day (source: FARS)
6693.000 2015 Injuries per day (source: GES)


Frequently Asked Questions

Technical assistance is available to States through the NHTSA Crash Data Improvement Program (CDIP) and Traffic Records GO Teams. CDIP and GO Team technical assistance can be requested by submitting an application to your State’s NHTSA Regional Office. The Training and Technical Assistance application can be found here.

A State can request a MMUCC Mapping at any time by submitting an application to their NHTSA Regional Office. If your State is considering an update to its crash report or statewide crash database, MMUCC Mapping results provide decision-makers with State-to-MMUCC compatibility and the information they need to prioritize changes. The Training and Technical Assistance application can be found here.

The Mapping to MMUCC 5th Edition section of the MMUCC 5th Edition Guideline provides detailed information on the MMUCC Mapping rules and process.

There is a MMUCC Crash Report Form that can be found in Appendix C in the MMUCC 5th Edition Guideline or by clicking here for a full-size version. 

States are also welcome to request the editable version of the MMUCC Crash Report Form to modify and use as needed by sending an email to the Traffic Records Team.

A summary of changes can be found in Appendix B of the MMUCC 5th Edition Guideline (2017).

MMUCC is a voluntary guideline that represents a minimum, model set of variables (data elements) that describe a motor vehicle crash. Data elements were incorporated into MMUCC if they were deemed necessary (needed for decision-making purposes) and comprehensive (included all aspects of the issue or problem being described).

While the MMUCC guideline is a voluntary standard designed for States to use at their discretion, specific parts of the standard have been incorporated into several regulatory requirements. States are currently required to adopt the model distracted driving data element in order to qualify for §405(e) distracted driving incentive grants. In addition, States will also be required to adopt the “serious injury (a)” attribute of the injury severity element by April 15, 2019, per FHWA’s Safety Performance Management Measures Final Rule (23 CFR 490) and NHTSA’s Uniform Procedures for State Highway Safety Grants Program Interim Final Rule (23 CFR 1300).

MMUCC is a collaborative effort between NHTSA and GHSA, States, data collectors, data managers, data users and safety stakeholders. Prior to each publication, an expert panel convenes to review all proposed changes to determine what will be included. Every change is considered - both for its merits and how it will impact the existing elements. The panel's primary focus is to strike a balance between the data we'd like to have, what law enforcement can reasonably collect, and what data managers can link or derive. 

Proposed changes can be submitted to the Traffic Records Team and should include the following information: 1) reason for change, 2) specific change requested (draft of new or changed element/attribute), and 3) any updated or new edit checks.