The DOT Alerts API: What It Takes to Get Live Closures From 50 States

Every state DOT publishes live road alerts — closures, crashes, construction, chain controls. That data is public, current, and free to read. Getting all 50 states into one feed a product can actually use is a different problem, and it's a bigger one than most teams expect going in.

Fifty agencies, no shared standard

Washington answers in a REST API with an access code in the URL. Arizona and several other states run on a shared platform called ibi511, keyed by an API key. Colorado answers in GeoJSON, with its coordinates ordered backward from most other feeds. Some states publish through WZDx, a federal open-data spec built for work zones. Others run on plain ArcGIS map servers built for GIS software, not apps. A few small states have no dedicated traffic system at all, and their alerts live inside a general government open-data catalog instead.

Access is its own project

Some feeds require registration, an API key, and a signed terms agreement before the first request goes through — and a few need direct back-and-forth with an agency's own IT staff. Multiply that by fifty and at least one will be genuinely unusual: one state's system blocks the network range most servers run on outright, so its feed has to be fetched from a separate process on a different network and stored somewhere the main system can read it.

The work doesn't stop at launch

Route names, mile-marker formats, and direction codes vary by state and change without notice. One state's alert system calls a road “101-LOOP” while its own mile-marker data calls the same road “SR-101,” and a translation rule that works for one state's platform can break silently on the next state's. A feed that goes stale or moves its endpoint fails quietly, unless something is watching every source, continuously, not just at launch.

What's on the other side of that work

MileCheck already did this once, in production, for a consumer app live on iOS and Android: mile markers in all 50 states, live DOT alerts in 50 states, normalized into one schema regardless of which upstream platform format the state actually publishes in. It's available two ways. As a licensed data feed a platform integrates into its own product — API access, a static or continuously synced dataset, or a white-label SDK, depending on what fits. Or already built into a fleet tool: MileCheck is live on the Geotab Marketplace as an Add-In for MyGeotab and Geotab Drive today — see how it works inside Geotab.