Bridges & infrastructure condition
The US National Bridge Inventory in Python: mapping 624,193 highway bridges, condition ratings, age, traffic on poor bridges, scour, inspections and the format traps.
Every public highway bridge in the United States longer than twenty feet is inspected every few years, and the results go to the Federal Highway Administration as the National Bridge Inventory: 624,193 bridges in 2025, each with its location, owner, age, traffic, materials and condition ratings for deck, superstructure, substructure or culvert. It is the most complete open record of the condition of any national infrastructure, and the source behind every count of poor or structurally deficient bridges.
The guides here read and map the inventory, explain how the ratings become Good, Fair and Poor, rank counties three ways, follow bridge age and the Interstate generation, weight condition by traffic, and find scour-critical and load-posted bridges. Three pages deal with the traps: coordinates packed as degrees, minutes and seconds, ratings of N, and inspection dates that general-purpose parsers misread.
🧭 Start with the concepts
The ideas the how-to guides below assume you already have.
⚙️ Then do the task
Step-by-step walkthroughs with code you can copy and adapt.
- How to Map the National Bridge Inventory in Python
- How to Find the Counties with the Most Bridges in Poor Condition
- How Old Are America's Bridges? Year Built, Reconstruction and Condition
- How to Weigh Bridge Condition by Traffic: Daily Crossings on Poor Bridges
- How to Find Scour-Critical Bridges Over Rivers
- How to Analyse Load-Posted and Closed Bridges in the NBI
🔧 When it breaks
The errors this topic produces, with the cause explained rather than just the command.
Related topics
Subjects that keep coming up alongside this one, most overlap first.