ADOT Data Supply Chain & ARNOLD

ARNOLD and the Data Supply Chain are topics and ideas imperative to supporting federal reporting in DOT's. ARNOLD is the bases for the road network deliverable to FHWA, and the Data Supply Chain is the way the data is collected and compiled. Since ARNOLD is now a Federal requirement, having local input on the statewide road network is imperative to a accurate submission. This also helps inform Emergency 911 networks, as emergency services having an accurate roadway systems allows for quicker emergency responses.

The Data Supply Chain is the way different entities share and deliver route network data to the state in order to have a complete spatial picture of the road network regardless of functional class. Creating these mechanisms where local agencies can communicate and contribute is the way to be successful in statewide network unification. Arizona Department of Transportation, with support from the Arizona State Cartographer and the E-911 community, has embarked on an initiative to generate a statewide linear referencing system with address range attributes. The source E-911 centerline files from all 15 Arizona counties are combined with the State Highway System (SHS, maintained by ADOT) arcs/routes to form the composite arcs and routes.

It's not just data being delivered up though! Part of the magic of the data supply chain is the pyramid of data owners to data users goes both ways. Data is shared in all parts of the pyramid. Local agencies and municipalities share data with the state and the state shares data with the locals. Each part of the data supply chain depends on each other.

At Arizona Department of Transportation (ADOT) there has been a long history of maintaining and supporting road centerline and linear referencing system network for more than 25 plus years. The network has been supported by many different software systems and people, but it always had the goal for inclusion of all public roads. For the moderate to large county datasets ADOT would choose to only do one or two counties every year at most and sometimes not even process a county for a couple of years. The result was the road network was becoming less and less current for the lower order roads.

In 2012 the United States passed MAP-21 Transportation bill into law. This law created the requirement for all states to report to the Federal Highway Administration (FHWA) a geospatial dataset representing all public roads. Subsequently FHWA began requiring this of State DOT's and called this data report the All Road Network of Linear Referenced Data (ARNOLD).

In the data supply chain process local E911/public works organizations maintain their centerline/route datasets natively within their county/regions. After polling the local organizations it was determined that these roadway datasets are managed not on a scheduled frequency but instead are typically updated as needed. Local agencies were given access to “submit your data” tools that resides within AZGEO where local agencies could easily provide their data to the data supply chain process. The AZGEO submittal tools ran a series of important validation and change detection processes on the submittal before ADOT was notified of new data. The ADOT Centerline Validation tools ingests the local suppliers roadway data and processes it through a series of data quality assurance tests.  The process includes both scalar (attributes) and spatial tests and are intended to catch most of the data issues that have been identified during previous submittal iterations.  Data quality assurance tests that are run include; proper field naming, proper field types, proper field values (null values, incorrect spacing, etc.), and spatial accuracy checks (overlaps, unlikely geometry, route bifurcations, etc.)  This toolset also normalizes the input data sets to a standard that can be used throughout the remainder of the unification data submittal process. 

ADOT's Linear Referencing System (LRS) network unifies the local GIS data to the state's LRS network. By unifying the GIS from the local network, ADOT is able to better represent all roadways in the state. This process, called unification, ingests locally owned roadways GIS data into the state GIS road network for the HPMS submissions and many other uses. Local providers upload their data to the  AZGeo Centerline Unification tool , where they will run their data through a series of validations, ADOT then runs change detection on that data and ingests any new/changed network into the ADOT GIS. This increases the spatial accuracy of ADOTS  ARNOLD.  By conducting this unification annually, the states LRS network can be its most accurate for the  ARNOLD ,  HPMS ,  CPM  and  roadway characteristics inventory . Having an accurate LRS network is important for the other items required for federal reports like HPMS and MIRE.

Arizona state DOT has put together several tools to help iron out the exact data supply chain. Currently, there are 3 different areas where ADOT uses the data supply chain to elicit local input; centerline validation, functional classification, and owner/maintainer.

Centerline Unification Process

The Centerline Unification process utilizes GIS technology and includes processes such as; data QAQC, edge-matching with demarkations, event creation, validation, etc. The Centerline Unification process also includes feedback loops to expose any useful findings back to the centerline providers for dissemination. There are 2 different unification tools local agencies need to consider. Validating their centerlines, and comparing their centerlines, these tools can both be run concurrently if both are necessary.

The tools to provide local data to the state uses the  AZGeo Centerline Data Validation System . This is the preferred for sharing centerline data, however, any legacy agencies that may have previously emailed or provided data via an ftp will still be accepted.

There are several validations used in centerlines aquisition. By uploading centerline data to the unification app, the data is run through these rules and errors can be identified. By running the data through these rules and identifying issues, problems with the data can be fixed and accurate data can be more easily incorporated into the statewide LRS network.

To learn how to use the Centerline Data Validation System app, click  here .

Other tools used to unify the networks are:

• AZGeo (Ticketing app)
• AZGeo Data Hub
• 1Spatial
  • Change Detection
  • 1Integrate
  • Rules Engine
• ESRI Change Detection
• Model Builder 
• Demarcation Points

Federal Functional Classification Change Request

Functional classification is an item required to be submitted with HPMS. Functional classification is a categorical assignment to a roadway based on its primary use, as well as several other factors like, traffic, urban/rural population, road connectors, etc... Functional classification of a roadway can effect the funds allocated to that agency from FHWA and project planning at all levels. This is why communication between the state (the designator of Functional Classification) and local agencies is important.

The data supply chain works in a circular fashion for functional class. Local jurisdictions may request changes to a roadways functional class, the state will then reject or approve the request, then send it to the FHWA division lead for federal approval. This process has to go through several levels of approval, the data supply chain builds the mechanisms for these approval steps. There can be several added levels as well, depending on the owner of the road, the local jurisdiction may also need approval from the county or COG/MPO. In order to accomplish these levels of communication, the AZGeo We Love Your Input app has been implemented as a way to inform and start the conversation on a functional classification change amongst all the stakeholders.

To learn more about functional classification and in ADOT see the links below:

•  Functional Classification Overview 
•  Functional Classification Change Request 
•  Functional Classification Rebalence 

Road Ownership and Maintainer Validation

Ownership and maintainers is another item required to submit for the HPMS report. The state has a good gauge on the state owned network, but welcomes input from local agencies on the ownership of the local system. In many cases, the interest in validating the states ownership network really comes down to the local agency interest on the accuracy of the data. The state encourages local agencies to validate ownership across the state so that the data quality can improve.

Where input on ownership is more important is in the Certified Public Mileage (CPM). Owner/Maintainers is a tool to determining roadways that should be included into the CPM. CPM is the number of public miles that are accessible for all standard passenger cars and generally publicly accessible. The CPM per each county, COG/MPO, city, and other regions are calculated and can affect funding going to said area and to the state itself. For this reason, having input from local agencies on what roads should or should not be included in CPM is imperative for federal reporting. This is included in the AZGeo Ownership Validation tool.

To learn more about CPM and Ownership validation, see below:

•  Ownership and Maintership 
•  Certified Public Miles (CPM) 
•  Ownership/Maintainership Validation Tool 

Arizona takes GIS data that exists in each of its local agencies and unifies them to create one LRS network for the whole state. Starting at the local level and building into the holistic LRS network unifies linear data coming from local agencies with the state system. Arizona partners with AZ State Land and ADOA to implement the 1Spatial 1Integrate tool to ingest E911 network providers to map total roadways in the state. This is in development in emergency response called NextGen911. This requires emergency response call centers to use a Geospatial Data set for locating where to send first responders and help route them to the proper location.

Arizona uses a stitching process to connect road centerlines where ownership changes between networks. This happens when different road owners represent their road centerlines in different places on the same roadway, where ownership changes. Continuity between adjoining agencies is established through a set of demarcation points. Geoprocessing tools from the  Works Consulting's suite  of extensions for ArcGIS allow for the conjoining of the independently-maintained datasets through analytical geoprocessing models to form a complete statewide LRS with associated statewide E-911 range-addressed arcs. 

Using the demarcation points, the entire state can be assembled (or re-assembled) in minimal time to provide an up-to-date centerline without redundant editing between multiple agencies. All assembly is through geoprocesses. Demarcation points are actually "short-lived" as they only perform "work" when arcs/routes do NOT already intersect them. Therefore, adherance of local governments to the demarcation principle -- through the ultimate editing of local street centerlines to intersect the demark points -- will actually render the demarcation points no longer necessary. However, the demarcations will remain -- each point a negotiable component of the GIS schema at Arizona DOT -- so that intersections can be guaranteed between centerlines and routes of adjoining agencies.

The All Roads Network of Linear Referencing or ARNOLD are new requirements for state DOT’s HPMS submittals. These overall requirements are improving reporting and GIS for HPMS, but can be complex and confusing. Each state implements the ARNOLD requirements slightly different, but still must follow the general guidelines to satisfy the GIS requirements.

ARNOLD is the spatial data for linearly referenced GIS road network for each state. This is required for reporting as it is the spatial tie for all the road data. This must include local roads that may not have previously been spatially referenced. This change makes it possible to retrieve crash data on local roads that previously was not geographically referenced. States are now responsible for supplying the distinction between public and private roads and store this information in the roadway network. While HPMS submissions do not require private roads to be reported for event and ownership data, doing so is incredibly beneficial to Emergency Response and the spatial road network accuracy. For more information on ARNOLD, read the   ARNOLD Reference Manual  . Along with HPMS submissions, this also plays a part in the Model Inventory Safety Exchange (MIRE) report. With ARNOLD increasing the total GIS, crash data and more spatially referenced local roads greatly help E911.

Other than generally increasing the GIS behind the road network this is the spatial representation that supports submission for all other items required for HPMS. Without a thorough and accurate ARNOLD LRS, the submission of other items cannot exist, as they don’t have a place to sit in the GIS.

ARNOLD is also important for the Certified Public Miles, this allows for a more accurate representation of total mileage for a state DOT because all roads are being spatially referenced. This LRS database acts as validation for a state's total mileage. HPMS requires certified mileage for reporting purposes, it is important to consider these variables for verification. This increase can affect funding from FHWA as including local roads will result in an increase of CPM, which directly affects funding for state DOT's. Since ARNOLD is increasing the GIS behind CPM, this requires Linear referencing for all roads. This unifies the local roads into the CPM and Linear Referencing System (LRS) using GIS. This change makes it possible to retrieve crash data on local roads that previously was not geographically referenced. While ARNOLD is important for CPM, it also plays a huge in many other aspects of HPMS and other important national reports: 

• All public road centerlines
• Bureau of Indian Affairs (BIA) and Tribal deliniations
• Fiscal Management Information System (FMIS)
• Bridge project locations
• Fatal and serious injury crashes
• Link to Model Inventory of Roadway Elements (MIRE) and other safety data
• Freight
• Dual Carriageways
• Truck Network
• Traffic volumes and vehicle tracking
• Routing topology
• Performance measures for safety
• Crash locations by Urban Area and Metropolitan Planning Organization (MPO)
• Vehicle Miles Travelled (VMT) by urban area and MPO
• Performance Measures for Pavement
• Pavement Condition

The key change that happened between HPMS requirements and ARNOLD requirements lies in the roads that must be reported. Previously, only federal aid roads were required to be GIS supported, but now all roads must be included in the state's Linear Referencing System (LRS). The way states go about gathering this information can differ state to state. Some use local agencies to support their GIS, other states may use data from open street view, or TIGER files to create their LRS network. The way each state puts together their LRS network is the data supply chain. ARNOLD explains 4 ways the data supply chain can work, these are broken down into 4 categories: 

1. Local government supplies roads data to the State DOT.
2. Commercial and third-party road centerline data supporting a State DOT.
3. The State DOT does it all.
4. Hybrid approach.

These are also broken down into 5 classes that distinguish the way the GIS is built, 1. Road centerline geometry 2. Basic road attributes (e.g., road names) 3. Address ranges, 4. LRS control, 5. Network topology to allow routing.

Still having trouble understanding what ARNOLD is? Reach out to the Arizona Department of Transportation, Multi-Modal Planning Division for further explanation.

If you would like more information about the different variables required for HPMS and other transportation reporting, feel free to visit the   Data Analytics section website   or another related story map below:

 Certified Public Miles (CPM)  

  Traffic: How is it reported?  

  Highway Performance Monitoring System (HPMS)  

  Lane Miles Vs. Maintenance Lane Miles 

  Contact