If you've ever sat at a drawbridge watching a single sailboat drift through while forty cars idle behind the gate, you've probably wondered: who decides when this thing opens?

The answer is the federal government, in writing. Every regulated drawbridge in the United States — all 800-plus of them — has its opening rules spelled out in a Coast Guard regulation called 33 CFR Part 117. When the bridge opens on signal, when it only opens on the hour and half-hour, when it's locked shut for rush hour: it's all in there, bridge by bridge, down to the minute.

Almost nobody has ever read it. It's a legal document written for bridge tenders and boat captains, not for the drivers sitting at the gate.

So we turned it into maps.

Florida first — with live status

Florida has more regulated drawbridges than any other state: 109 of them, most strung along the Intracoastal Waterway, where boats get priority and drivers get the gate. If you commute across one in Fort Lauderdale, Miami, or the Palm Beaches, the bridge schedule quietly runs part of your life.

The Florida drawbridge map shows every one of them. And for the bridges FDOT has wired with sensors — about twenty so far, mostly in Miami-Dade, Broward, and Palm Beach — the map shows live up/down status, refreshed every 30 seconds. Red means the bridge is raised right now. Tap any bridge and you get its federal opening rule: on signal, on the hour, or locked during peak traffic. There's a searchable list too, because Florida has a lot of bridges.

Louisiana, New Jersey, North Carolina, Washington, Seattle

Louisiana turned out to be the sleeper: the state has more movable bridges than almost anyone, and DOTD publishes live road-and-marine status for all 100 of them — so that map shows you, right now, which bridges are closed to cars. The New Jersey map covers the Shore's Intracoastal crossings — Route 35, 71, 88 — with each bridge's opening rules and its bridge-house phone number. North Carolina shows only the 8 bridges that still actually open (several famous ones — Surf City, Sunset Beach — were replaced by fixed spans, and the federal rulebook hasn't caught up; we verified against NCDOT's inventory). Washington adds Hood Canal and the rest of the state, and Seattle keeps its live 30-second status — the original.

Behind these three pages is the full national dataset: every regulated drawbridge in 37 states, each with its opening schedule and its exact citation in the federal register. More state pages are coming — and live status gets added anywhere a DOT or a city publishes a feed.

Why a mile-marker app cares about drawbridges

MileCheck exists because the road system publishes real information that never reaches the apps people actually drive with. Lane closures sit in state DOT feeds. Drawbridge rules sit in a federal regulation. None of it shows up in mainstream navigation — not because it's secret, but because nobody connected it.

A drawbridge is the purest example there is. Your nav app will happily route you across a bascule bridge without mentioning it can open for boat traffic in the middle of your trip. The rule that governs that opening has been public since before smartphones existed.

Connecting that kind of data to drivers is the whole idea behind MileCheck — mile markers, DOT alerts across the country, border waits, and now the drawbridges.