Webinar 41
MIRE Data: A GIS Perspective

January 29, 2020

Summary of the Federal Highway Administration’s Quarterly Webinar


The Federal Highway Administration (FHWA) promotes geographic information systems (GIS) as a means to more effectively manage and improve transportation systems. One of the ways that FHWA does this is through its GIS in Transportation program,1 which identifies timely and critical GIS issues and topics in transportation and connects transportation agencies with available resources and best practices. The webinar summarized here is part of a quarterly series organized through the GIS in Transportation program.

Patrick Whiteford (pwhiteford@azdot.gov) and James Meyer (jmeyer@azdot.gov) of the Arizona Department of Transportation (ADOT) presented ADOT’s steps taken and best practices incorporating Model Inventory of Roadway Elements (MIRE)2 data element onto their linear referencing system (LRS).

Sharon Hawkins (sharon.hawkins@ardot.gov) of the Arkansas Department of Transportation (ARDOT) presented ARDOT’s current efforts to meet the MIRE Fundamental Data Elements (FDE) requirements for intersections and interchanges. This includes the software and methods needed for completing the requirement as well as an introduction on analyzing the information they collected so far.

A recording of the webinar is available here.

MIRE Case Study – Arizona DOT

The ADOT Planning Division is responsible for maintaining the authoritative LRS to support Federal reporting systems, including the All Road Network of Linear Referenced Data (ARNOLD) and the Highway Performance Monitoring System (HPMS). When the U.S. Department of Transportation (USDOT) announced the MIRE requirements, the State Planning Division acquired the responsibility to maintain the MIRE data elements. ADOT started evaluating its data to determine what it had and needed. The State DOT identified a large amount of available data for the State maintained network; however, the State network did not have complete data for all roads, only those within their jurisdiction. The State DOT GIS team collaborated with the Safety team to develop a crosswalk table to identify currently housed data and data needed. Additionally, the teams determined that they would collect safety data for any route classified above a local classification. The two teams identified they needed many data attribution changes to conform to the MIRE requirements, which would also require collaboration with the IT team. ADOT realized that to do a holistic data analysis, it needed data on roads not owned by the State, which would require additional support. The State DOT developed needs by road functional class and a contract to collect the needed data. Currently two years into the data collection process, ADOT has completed data collection on half of the contracted mileage. In addition to collecting existing data, it identified the need to keep the data up to date. ADOT now looks to use their financial management system to track projects as they happen and plans to leverage its CAD files to keep its LRS updated. ADOT is also exploring solutions to capture maintenance activities sooner. When completed, the hope is to have the State’s LRS inform all other State agencies.

ADOT learned several lessons from this project. The concept of route dominance, which means that in a route network there are many physical roads that carry many different road names, played an important role in many cases. It is important to assign attributes on the dominant roadway to ensure sustainable data management. Additionally, the concept of one source of truth also played an important role during this process. One source of truth refers to having any piece of data maintained in one single location and referred to by other databases. An additional lesson learned was the need for training and knowledge management. ADOT developed two knowledge management products. The first was a MS OneNote file that contains all the MIRE data procedures and processes. The second was the development of storyboards to ensure staff throughout the department were able to speak the same language by understanding the terminology.

MIRE Case Study – Arkansas DOT

In Arkansas, the methodology to meet MIRE relies on the ARNOLD system. ARDOT methodology started by identifying what data are needed for intersection. A software called Intersection Manager from Transcend Spatial Solutions aided in identifying the necessary data elements. Intersection Manager is an ESRI extension or add-on that utilizes current LRS, Functional Class, Average Daily Traffic (ADT), and other optional datasets to create and then update intersections on the State network.

Arkansas provided an overview of the data elements being collected for an intersection. These elements include a unique junction identifier, which is an auto-numbered ID. In Intersection Manager, users note identifiers for intersecting routes for a given intersection. Intersection Manager also generates approach segments for the intersections at the distance preferred by the user. At ARDOT, 100 feet serves as the test segment length. The Intersection Manager also generates the approach angle, direction, and begin and end mileposts for the segments. The Intersection ID ties to the data throughout the process. For the ADT MIRE requirement, ARDOT uses a SQL statement to pull the ADT values that fall on the same LRS Road ID and within the mileage for the intersection to populate those values yearly. After the intersections generated, ARDOT focused on attributing the Junction Geometry and Traffic Control for the intersections. The State DOT developed a simple manual with visual examples of the types of geometry and traffic control to help ensure a degree of governance on how users entered the data into the system. ARDOT then created domains for the Geometry and Traffic Control fields so that users would have a drop-down interface to choose their selections. Users then published the intersection points through ArcServer and then developed an ArcGIS Online application for others to use.

For intersection attribution, users can zoom in on a map and click on a specific intersection that they want to attribute. Users can see a Google View tool that centers the latitude and longitude of the intersection on the Google Map and provides them with the ability to view imagery and street view to make an informed decision on how to attribute the intersection. Once the user knows the geometry and traffic control, they can go into Edit mode and use the drop-down selections to choose both attributes. Then they will mark the intersection as complete and move on to the next one. Within the Intersection Manager tool, there is an option to tie the Interchanges (also a MIRE requirement) to the intersections. This can create a parent/child relationship between the two features so that individual intersections can be within the complex intersection or interchange. When the user chooses the intersection, its unique ID then ties it to the complex intersection.

At the time of the webinar, ARDOT estimated that it will take approximately 15 to 17 weeks to finish the State Highway intersections before it moves on to local road intersections. This work involves two employees currently working full-time and four employees working part-time between other duties. ARDOT hopes to be done with this process for all public roads in 2021.

One lesson learned through the project is that not every intersection is a true intersection. This can happen when a road name changes where there is no true intersection, an overpass or underpass can create a false intersection, or other similar issues. ARDOT has been looking at the pseudo nodes in the data and then determining if an intersection that is also a pseudo node is indeed false. For the most part, that is the case. Seven percent of the initial run, or about 16,000 instances, fall in this category.

Questions & Answers

Does ADOT use Roads and Highways for HPMS?
ADOT uses ESRI’s Roads and Highways to maintain the LRS and roadway characteristics.

In ADOT, is the data kept as an event on the LRS or as separate tables in GIS?
In ADOT, the data are all kept/maintained as events on the LRS in the GIS.

How is ADOT planning to update your local roads?
ADOT coordinates with its E911 office and locals to collect and update data that are part of its LRS.

In cases where Google Street view has no imagery, how does ARDOT handle intersections?
In those cases for the State highway system, ARDOT uses its Fugro photo log. For intersections off the State highway system, it marks the intersection as incomplete.

How does ARDOT handle intersection changes?
ARDOT is not a Roads and Highway State. Since the Intersection Manager knows where the ARNOLD data resides, and the data are temporal, the program can identify what intersections are present at any given point in time. Due to the temporal nature of the Intersection Manager, ARDOT is able to retire intersections as changes happen.

How did ARDOT identify and handle pseudo intersections?
ARDOT started with the bridge database to address pseudo intersections caused by bridges. There are other databases that are referenced to remove pseudo intersections. ARDOT uses queries to conduct this analysis.

1 See the FHWA GIS in Transportation website for details: https://gis.fhwa.dot.gov/.
2 MIRE is a recommended listing of roadway inventory and traffic elements critical to safety management: https://safety.fhwa.dot.gov/rsdp/mire.aspx.

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