The Federal-Aid Highway Act of 1968 required the Secretary of Transportation to establish the national bridge inspection standards (NBIS) for the safety inspection and evaluation of highway bridges. The mandate resulted in the creation of the National Bridge Inventory (NBI) database to collect inventory and inspection data for all publicly owned highway bridges longer than twenty feet located on public roads. States were in turn directed to collect and submit highway bridge data for the NBI. Consequently, the NBI, a unified national repository, is updated continually by bridge owner agencies nationwide as a part of their independent bridge management program processes. This continual update of data enables the Federal Highway Administration (FHWA) to make budget allocation decisions knowing the data is current. When it comes to ancillary structures1 along highways, however, a unified repository of public structures does not exist. This is changing, as evidenced by the National Structure Inventory (NSI) initiative of 2019 by the US Army Corps of Engineers.

The mission of the NSI initiative is to support those responsible for the evaluation of damage to infrastructure from floods and other hazards. A prerequisite for this mission is a national repository of infrastructure information that is consistent, regardless of its source, and stays current. A review of the nature of the initiative, and of how the US Army Corps of Engineers has implemented it, offers valuable insights for State Departments of Transportation (State DOTs). These insights, in addition to improving how they maintain and access data for their structure inventory and inspection programs, enable State DOTs to leverage their distributed inspection and maintenance workflows for doing more with less.

The scope of the NSI initiative is nationwide, its focus is narrow (assess the value of damage), while data inputs are coarse and distributed (Hazus from FEMA, CoreLogic from DHS, InfoGroup business layer from ESRI, Building footprints from Microsoft, Demographics from US Census, School data from NCES, Elevations from USGS). On the other hand, the scope of a State DOT's ancillary highway structure initiative is statewide, its focus is wide (plan, design, construct, maintain, retire), while data inputs are fine (engineering-scale 3D geometric and geospatial models, engineering drawings, inventory and condition data, access points, inspection data, maintenance and repair) and widely distributed (planning team, inspection team, design team, construction team, operations team, maintenance team).

Key data management insights from the NSI initiative for State DOTs looking for transformative value from their ancillary structure program investments include:

  • Establish a purpose-fit common data model agnostic of system or process
  • Segregate open and closed elements of data model to secure sensitive information  
  • Implement connectors that transform and load source-data to the common data model   
  • Nurture data connection relationships with local jurisdictions and other State DOTs

Not only is there now an imperative to leverage technologies, such as drones for visual inspections and sensors for monitoring condition, but to also leverage no-code and low-code tools, such as Power BI and Power Automate that empower engineers to develop project-specific one-off solutions in days that would otherwise take months with traditional programming tools.

For an industry report based on research of the current state of ancillary structure programs at State DOTs, or for an assessment of the ancillary structure program at your DOT, email info at our domain address.


1 The term ancillary highway structure refers to structures for highway signs, traffic signals and high-mast lighting, and to retaining walls and noise barriers.