A Proposal for National DOT Geospatial Data Standards
As a leading advocate of intelligent transportation system (ITS) and transportation technologies, the United States must take a hard look at the current state of the geospatial data standards and methodologies that support the nation’s land transportation network. According to the Federal Highway Administration (FWHA), in 2017 the U.S. reported a total of 4,146,000 miles of paved and unpaved public roadways. These roads are managed and maintained by various jurisdictions—the FHWA, state departments of transportation (DOT), state and local governments and private owners—each establishing its own standards for road design, regulation and management.
While today’s localized approach works to a certain degree, it will not serve future transportation modality well. The careful study of future ITS and autonomous driving requirements clearly demonstrates the need for a land transportation network that satisfies future transportation realities. As a nation, our approach to managing the national land transportation network is problematic, and I would like to discuss a few issues that may further hinder the introduction of ITS and autonomous driving.
National Roads Database
There is no single jurisdiction responsible for managing the national roads infrastructure database according to set standards. Roadway data is scattered across agencies and often not carefully communicated. Modern cloud technology enables the hosting of a massive national roads infrastructure database that can be accessed by all users. Such a central geodatabase would make information updates easier and prevent duplicate efforts.
At this point, I must acknowledge the work of the U.S. Department of Transportation in developing and maintaining related projects such as the National Transportation Atlas Database and National Transit Map. Managed by the Bureau of Transportation Statistics, these sources are very useful for many studies and analysis.
Geospatial Data Standards for Road Infrastructure
Even if road management remains the responsibility of different agencies, we must establish a consensus on the standards used when capturing geospatial road map and inventory data. Such standards should benefit and be closely linked to Open Geospatial Consortium (OGC) standards and practices to best simplify the development of a national road database. While the U.S. Department of Transportation and the Federal Geographic Data Committee are currently developing geospatial road standards, the effort is not yet complete and does not reflect the enforced national standards I am discussing in this piece.
Such national geospatial standards must be designed around the following criteria:
- User-centric rather than device-centric
- Multi-modal, with various ways for users to interact with desktop computers, tablets and smart phones
- Centered on user preferences or user-selected methods/formats for adding to or extracting from the database
- Compatible with and adaptable to innovations such as artificial intelligence and the internet of things
Positional Accuracy Standards for Transportation Projects
State DOTs invested in and developed their own geospatial data standards, positional accuracy standards, and best practices and guidelines. This effort resulted in uneven measures for dealing with the same geospatial data and technologies. These state-based standards vary widely depending on the state DOTs’ resources and the technical reach of their staff. Some standards were poorly written, and many are outdated (designed for decades-old technologies). A single set of national DOT positional accuracy standards will benefit all state DOTs while setting the stage for facing future challenges to ITS implementation.
Access to existing geospatial information within different agencies is constrained by multiple factors, and many of the above-mentioned requirements are supported by the National Spatial Data Infrastructure requirements of the FAA Reauthorization Act of 2018. An excellent vehicle for such implementation is the development of a national infrastructure map, which was recently proposed by an alliance from the National Academy of Public Administration, American Geographical Society, Arizona State University and National Academy of Construction. A national infrastructure map would provide political leaders and citizens with readily available, systematic and comparable location-based information to support an informed political process for determining and acting upon priorities. While this map is not about roads exclusively, roads and associated infrastructure can be added as layers to the geodatabase.
The national DOT geospatial data standards and database should contain the following key elements:
- Enterprise approach to data management
- Well-defined format and metadata
- Data dictionary and glossary
- User guides
- Best practices manuals
- Mapping conventions based on OGC geocoding
- Symbiology when possible
- One specified positional accuracy standard that is sensor agnostic and data driven
- Engineer and planner participation
The widespread adoption of GIS for capturing location-based infrastructure data by public agencies and private organizations will aid in the database and standards creation.
Finally, the successful development and integration of the standards and database will require a national transportation-related geospatial data assessment study. This study will provide the following:
- Inventory of existing geospatial data within multiple transportation agencies
- Survey users’ requirements within the DOTs
- Planning and feasibility analysis activities
- Design work activities
- Resource management activities
- Return on investment estimate (benefits versus costs)
- Recommendations for additional program beneficiaries (multiple users increase cost efficiency)
- Proposal for a national strategy for DOT-related geospatial data governance
The United States Geographical Survey’s 3D Elevation Program (3DEP) is a precedent-setting success story. The national survey and study that preceded the 3DEP implementation led to the program’s safe and successful implantation. We should follow a similar approach for our national transportation standards and database implementation.