Embedded Files
Background & History
Background & History
Good data and effective analysis are key to making sound decisions on the safety, design, and operation of roadways. The Model Inventory of Roadway Elements (MIRE) is a recommended listing of roadway characteristic and traffic inventory elements critical to safety management. It is a guide to help state transportation agencies improve their roadway and traffic data inventories to support a State's advanced safety analyses.
The first MIRE report was published by the Federal Highway Administration (FHWA) in 2007 and led to the publication of MIRE 1.0 in 2010, the first guideline on what should be included in future reports. MIRE was then adopted into law starting with the Moving Ahead for Progress in the 21st Century Act (MAP-21), signed on July 6, 2012 as Public Law 112-141, which called for improved data for better safety analysis to support the development of States’ Strategic Highway Safety Plans (SHSPs) and Highway Safety Improvement Programs (HSIPs). These requirements continued to be supported in the Fixing America’s Surface Transportation Act (FAST Act), signed on December 4, 2015 as Public Law 114-94. MIRE is specifically named in these acts as a guide for States to focus on items that are most important for safety analysis, with a recommendation that States shall have access to all required elements by September 30, 2026 [23 CFR 924.11(b)].
Due to changes in technology and available data that occured since MIRE 1.0 was released, FHWA published a refined version of the report, called MIRE 2.0, in 2017. These refinements further aligned MIRE to other Federal datasets and requirements as well as took into account changes in the Highway Performance Monitoring System (HPMS), such as the 2014 requirement that it include a spatial representation of all public roads in the state, referred to as the All Roads Network of Linear Referenced Data (ARNOLD).
In 2024, FHWA published MIRE 2.1. This edition serves as a minor update to MIRE 2.0, and provides additional clarification on the three categories of data requirements, reordered the data items to list FDEs first, and includes updated graphics.
Fundamental Data Elements (FDE)
Fundamental Data Elements (FDE)
MIRE 2.1 includes a list of 109 elements, or road attributes, where FHWA recommends data for safety analysis. However, MAP-21 and the FAST Act requested FHWA establish a subset of elements that States would be required to submit data for, leaving the other elements as optional. 37 elements were identified as required, and are referred to as Fundamental Data Elements (FDE). These elements are foundational to enabling jurisdictions to analyze crashes on their roadways relative to the expected average crash frequency given the roadway and traffic characteristics at each location.
The MIRE FDEs includes data elements that are already reported in HPMS. However, there are notable differences between HPMS and MIRE, including:
All 37 FDEs are required for rural minor collectors (functional class 6)
The following elements will be required for all local paved roads (functional class 7)
Surface Type
Number of Through Lanes
Average Annual Daily Traffic (AADT)
The surface type required is less detailed where HPMS surface type is not required:
Asphalt (includes AC Overlays, Bituminous, etc)
Concrete (includes PCC, JPCP, ect)
Other Paved Surfaces (Brick, Cobblestone, etc)
Unpaved
Where FDEs are required varies for roadways, intersections, and interchanges/ramps as well as by the road's functional classification and surface type. Ownership is not a factor in the FDE requirements and includes all public roadways. Table 1 below summarizes the FDEs and locations that States will be required to report.
Note that intersection, interchange, and ramp FDEs are only required on roads with functional class 6 and above.
Table 1: MIRE 2.1 Fundamental Data Elements (FDE). Definitions for each of these items can be found in the MIRE 2.1 Report, starting on page 30 (PDF page 54).
Reporting MIRE FDEs
Reporting MIRE FDEs
As of August 2024, MIRE only requires states to have access to data for each of the FDEs per the above table no later than September 30, 2026. However, there is no requirement for states to submit these data to FHWA. Instead, states must be prepared to provide these data on-request, either by FHWA or other agency or organization.
FHWA is working on implementing a way for states to submit MIRE FDE data as part of the annual HPMS report. However, at this time, submitting MIRE data remains optional and at the discretion of the states.
Coordinating Data Collection with Local Agencies
Coordinating Data Collection with Local Agencies
IMPORTANT
ADOT is ultimately responsible to collect these data elements. However, ADOT would like to reduce duplication by collaborating with local agencies on MIRE FDEs. This means ADOT would like to ingest local data were it already exists, or assist with additional funds to support local agencies in collecting these data. In cases where MIRE FDEs do not exist, or the local agency is not interest in collecting this data, ADOT will collect the data themselves.
Meeting the MIRE requirements will not impact local transportation budgets.
The ADOT Data Analytics team has already implemented strategies to collect many geospatial data elements on local roads.
ADOT Data Supply Chain & Centerline Unification Project: Collects centerline geometries from County 911 systems on an annual basis, allowing ADOT to have a statewide spatial representation of all public roads, including local roads
Highway User Revenue Fund (HURF): Source of information helpful for ADOT to calculate Arizona's Certified Public Mileage (CPM)
ADOT We Love Your Input website: Allows local agencies to submit requests for changes to functional classification, ownership, and maintainership for local roadways
It should be noted that none of these projects collect AADT, surface type, number of lanes, or intersection data. While some of these can be estimated, ADOT plans to work with local agencies to identify strategies to collect more of these data. It is important to know that ADOT is ultimately the responsible party for compiling the MIRE FDE datasets and, while ADOT may ask for assistance from local agencies, it will be the state agency's burden to collect or calculate these data.
Frequently Asked Questions (FAQ)
Frequently Asked Questions (FAQ)
Is there a penalty for states that do not meet MIRE requirements?
Is there a penalty for states that do not meet MIRE requirements?
While there is no direct penalty to states, to be eligible for HSIP funds per 23 U.S.C. 148(c)(2)(A) states must have safety related data available to identify safety problems and perform countermeasure analysis. MIRE is a comprehensive list of data that could be used to support safety analysis, and the FDEs are the foundation to performing safety analysis. If MIRE FDEs are not collected, it may not be possible for states to perform the analysis required for HSIP eligibility.
Is it true that MIRE requires AADT for all public roads?
Is it true that MIRE requires AADT for all public roads?
MIRE requires Average Annual Daily Traffic (AADT) to be reported on all paved public roads. Traffic does not need to be reported for any unpaved roads.
For paved local roads, where functional classification = 7, local agencies do not need to collect traffic counts for all of these roads. MIRE allows States to report estimates, which are calculated based on AADT from other nearby roads that already have counts available. ADOT will be responsible for calculating these estimates and the agency is currently working on a methodology to estimate local roads based on characteristics of minor collectors.
There may be instances where reliable estimates cannot be calculated for paved local roads due to a lack of nearby traffic counts. In these cases, ADOT will work with local agencies to determine the best way forward to get counts for those roads. However, it is important to understand that ADOT is the responsible party for compiling AADT for the MIRE report and, while ADOT may ask for assistance from local agencies, it will be the state agency's burden to build the AADT data.
Besides AADT, what is ADOT's plan to report other data items not currently required in HPMS?
Besides AADT, what is ADOT's plan to report other data items not currently required in HPMS?
While the additional AADT requirements are a primary focus, ADOT would also like to work with local agencies on getting surface type, number of through lanes, median types, and intersection data for rural minor collectors and paved local roads. These data are not currently reported through existing efforts, such as the ADOT Centerline Unification project or the Certified Public Mileage (CPM) effort via the Highway User Revenue Fund (HURF) reports.
In addition, ADOT would like assistance from local agencies on collecting additional data at intersections on locally owned roadways where functional class > 7, including the locations, type of traffic control, and geometry.
ADOT will work with local agencies, including Council of Governments (COGs), Metropolitan Planning Organizations (MPOs), and County GIS teams to determine how best to collect these additional elements. As stated earlier, ADOT is the responsible party for compiling these data for the MIRE report and, while ADOT may ask for assistance from local agencies, it will be the state agency's burden to build the data.
Is a new MIRE report expected?
Is a new MIRE report expected?
MIRE 2.1 was released in August 2024 and provided minor updates to MIRE 2.0 which was released in 2017. There is no timeline for the next update, and it is not anticipated to be released for several more years.
Additional Resources
Additional Resources
MIRE FHWA Website
Learn more about MIRE, the Fundamental Data Elements, and access a PDF copy of MIRE 2.0.
ADOT Data Analytics
Learn more about current local data collection efforts coordinated by the ADOT Data Analytics team.
ADOT GIS Analysis
Learn more about the ADOT GIS Analysis team, who manage the state GIS roadway database.
Page updated
Report abuse