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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation
FHWA Highway Safety Programs

INTRODUCTION

The need for improved and more robust safety data is increasing due to the development of a new generation of safety analysis tools and methods. These include the 2010 Highway Safety Manual (HSM) (2) the Interactive Highway Safety Design Model (IHSDM) (3)SafetyAnalyst (4), as well as the National Cooperative Highway Research Program (NCHRP) Series 500 Data and Analysis Guide (5). All these tools require crash, roadway, and traffic data to achieve the most accurate results. Having additional data can also help support States' Highway Safety Improvement Programs (HSIP) as discussed in the Federal Highway Administration's (FHWA) guidance (6).

Safety data are the key to making sound decisions on the design and operation of roadways. By having the necessary roadway, traffic, and crash data and merging those datasets, an agency can make more informed decisions and better target their safety funds. The ability to merge these data helps agencies to better:

  • Develop relationships of safety (including crash occurrence and severity) to roadway features and user exposure.
  • Identify location and characteristics of crashes.
  • Determine appropriate countermeasures and strategies.
  • Evaluate the effectiveness of safety treatments.

As shown in Figure 1, improvements in the data collection effort can drive more informed decision-making, which can lead to improved knowledge for decision makers to better target investments that provide the highest returns in reduced crashes and fatalities.

Improved Data Collection, More Informed Decision Making, Better Targeted Safety Investments, Improved Safety Outcome
Figure 1. Role of Improved Data Collection Efforts in Safety Outcomes.

The Model Inventory of Roadway Elements (MIRE) is a recommended listing of roadway inventory and traffic elements critical to safety management. MIRE provides a data dictionary with definitions and attributes for each listed element (1). MIRE is a guideline on the traffic and roadway data agencies should collect to improve their transportation safety management system. It provides a basis for a standard data inventory and helps agencies move toward the use of performance measures to track data quality and safety outcomes.

While MIRE provides a recommended listing of what roadway and traffic data to collect, agencies still struggle with how to merge and analyze those datasets. A critical step toward acceptance and implementation of MIRE is the conversion of MIRE, which is now a listing data elements, into a management information system (MIS) that will allow agencies to analyze and merge datasets. FHWA has undertaken the MIRE MIS project to assist States in developing and integrating the MIRE into an MIS structure that will provide greater utility in collecting, maintaining, linking, and using MIRE data. The MIS project includes the exploration, development, and documentation of the following objectives:

  • Mechanisms for data collection.
  • The identification of performance metrics to assess and assure MIRE data quality and MIS performance.
  • An efficient process for data handling and storage.
  • Details of database structure.
  • Methods to assure the integration of MIRE data with crash data and other data types, and that access to these data can be accomplished through the MIRE MIS.

The purpose of this report is to address the last three objectives. The first two objectives are covered in other reports from the MIRE MIS effort. This report provides a detailed overview of the MIRE MIS development effort which involved developing a conceptual structure of a MIRE MIS, developing a prototype based on the conceptual structure, testing the prototype using data from one of the Lead Agency Program States, and identifying the lessons learned and implications for further development and implementation.

The project team held a vetting workshop with representatives from nine States with expertise in safety data (e.g., roadway, traffic, and crash data), database management, and information technology (IT). The purpose of the workshop was to vet the structure of the MIS and obtain feedback on the feasibility of the MIS, barriers to implementation, and potential strategies to overcome those barriers. The feedback received from the participants was considered in the development of this report. The overall purpose of this report is to describe the concept of the MIRE MIS. This is not intended as requirements or a functional specification document.

MIRE DATA ELEMENTS

FHWA released MIRE Version 1.0 in 2010 and is available online at the FHWA Office of Safety website (http://www.highways.dot.gov//safety/data-analysis-tools/mire-fde/model-inventory-roadway-elements-mire-20-report). There are a total of 202 elements that comprise the MIRE listing. These elements are divided among three broad categories: roadway segments, roadway alignment, and roadway junctions. Examples of the MIRE data include:

  • Roadway classification.
  • Number and type of travel lanes.
  • Shoulder, median, and roadside descriptors.
  • Curve and grade information.
  • Traffic control devices.
  • Intersection features.
  • Interchange and ramp descriptors.
  • Pedestrian and bicyclist facilities.

Each data element has a priority rating, either "critical" or "value added." "Critical" elements are deemed necessary for States to conduct basic safety management and/or to use emerging safety analysis tools. Elements rated as "value added" are useful information, but not crucial in current versions of safety analysis tools. Each element listing also includes descriptions of alternatives to the preferred data elements if the intended data element is not readily available.

SUPPLEMENTAL DATA ELEMENTS

FHWA envisions MIRE as the primary standard for roadway inventory and traffic data variables; however, it does not contain all possible inventory data elements needed for every safety decision. Examples of additional supplemental databases include:

  • Roadside fixed objects.
  • Signs.
  • Speed data.
  • Automated enforcement devices.
  • Land use elements related to safety.
  • Bridge descriptors.
  • Railroad grade-crossing descriptors.
  • Safety improvements information.

Agencies or groups within departments of transportation (DOTs) may already be collecting these supplemental data elements in addition to what is in the primary roadway inventory. Identifying and linking these databases with the primary roadway, traffic, and crash databases can help provide safety practitioners a more robust dataset to support their safety analysis efforts. This report will explore methodologies for enabling these linkages.

BENEFITS OF ADOPTING A MIRE MIS

The MIRE MIS will help agencies in several ways. The MIS will provide a way to aggregate data from several existing systems to identify and objectively support cost-effective ways to improve safety. A secondary benefit will be the ability to identify high value targets for increased/improved data collection. Decision makers should feel more confident knowing that they are using data from a system that incorporates standardized data definitions and that the information provides a valid description of the roadways in a State or jurisdiction. Decision makers are increasingly mindful of the cost and value of the data they have available. Implementing a MIRE MIS can help a State save money on data collection by bringing in information through system interfaces, sharing resources, reducing overlaps, and utilizing more automated methods for merging data sets. States capable of doing this stand to benefit by providing decision makers with an enriched set of information. In addition to the benefits to safety, other areas may benefit as well. Asset management, highway operations, and maintenance functions of a typical DOT rely heavily on roadway inventory information to provide a first-cut analysis of where to spend current year resources and to project future resource needs. These programs will be able to work from reliable data to identify sites that share common features and descriptions. This information does not eliminate the need for field review, but it does help target the locations that are most likely to have a particular need based on their similarity to locations already programmed for work. Planners share in these benefits of a MIRE MIS with data that support detailed analyses of proposed project areas by having more precise and complete data on the roadway attributes at each site.

USE OF MIRE

MIRE is intended as a guideline to help transportation agencies improve their roadway and traffic data inventories. Given the current economic constraints, it is not likely that any one agency will collect all 202 elements on all roadways. Rather, agencies should identify which elements are most important to help improving their safety programs, and use MIRE as a guideline for how to define the elements and recommended attributes. The MIRE MIS effort will provide guidance on implementing MIRE. In addition to this report on the structure of the MIRE MIS, there are additional products available as a result of the MIRE MIS project. These are:

Data Collection:

  • MIRE Element Collection Mechanisms and Gap Analysis report.
  • MIRE Pilot Data Collection report.
  • Exploration of the Application of Collective Information to Transportation Data for Safety White Paper.
  • MIRE Data Collection Guidebook.

Performance Measures:

  • Performance Metrics for Roadway Inventory Data report.

Development and testing of MIS structure:

  • Development of a Structure for a MIRE Management Information System (this report).

These products are intended to further help State and local agencies improve the collection, maintenance, linkage, and use of their safety data. The lessons learned from the MIRE MIS effort and accompanying recommendations are intended as guidance to help support agencies efforts. Agencies are encouraged to tailor the recommendations and described practices to help fit their individual needs and agency objectives. All of the products of this effort will be available on the FHWA website https://highways.dot.gov/safety/data-analysis-tools/rsdp.

LEAD AGENCY PROGRAM

The purpose of the lead agency program was to determine the feasibility of collecting MIRE data and integrating it into a State's roadway inventory database. FHWA selected two States, New Hampshire and Washington, for the lead agency program through an application process. The pilot agencies determined where their inventories were deficient, and what elements they needed to add to accomplish their safety goals. New Hampshire served as a pilot for testing the MIS structure.