Bridges — FHWA National Bridge Inventory: Condition, Posting & Clearance

Search US bridges in the FHWA National Bridge Inventory. Scope with state, county (3-digit FIPS code), and/or condition (Good/Fair/Poor); optional filters: posting_status (open/posted/closed/not_yet_open), owner_code, scour_critical, year_min/year_max, min_adt, route, and q (text match on facility carried, feature crossed, location). Returns decoded records with condition rollup, posting status, clearances, and labels.

{
  "type": "object",
  "properties": {
    "state": {
      "type": "string",
      "description": "US state postal code, e.g. 'IL'"
    },
    "county": {
      "type": "string",
      "description": "3-digit FIPS county code within the state"
    },
    "condition": {
      "type": "string",
      "enum": [
        "Good",
        "Fair",
        "Poor"
      ]
    },
    "posting_status": {
      "type": "string",
      "enum": [
        "open",
        "posted",
        "closed",
        "not_yet_open"
      ]
    },
    "scour_critical": {
      "type": "boolean"
    },
    "year_min": {
      "type": "number"
    },
    "year_max": {
      "type": "number"
    },
    "min_adt": {
      "type": "number",
      "description": "Minimum average daily traffic"
    },
    "route": {
      "type": "string",
      "description": "Route number carried, e.g. '90'"
    },
    "q": {
      "type": "string",
      "description": "Text match: facility carried / feature crossed / location"
    },
    "limit": {
      "type": "number",
      "default": 100
    },
    "offset": {
      "type": "number",
      "default": 0
    }
  }
}

Get one bridge by its FHWA structure number (Item 8). Structure numbers are unique within a state; pass state to be exact. Returns the full decoded record.

{
  "type": "object",
  "properties": {
    "id": {
      "type": "string",
      "description": "Structure number, e.g. '016-0032'"
    },
    "state": {
      "type": "string",
      "description": "US state postal code, e.g. 'IL'"
    }
  },
  "required": [
    "id"
  ]
}

List bridges in one county (state + 3-digit FIPS county code), paged.

{
  "type": "object",
  "properties": {
    "state": {
      "type": "string",
      "description": "US state postal code, e.g. 'IL'"
    },
    "county": {
      "type": "string",
      "description": "3-digit FIPS county code"
    },
    "limit": {
      "type": "number",
      "default": 100
    },
    "offset": {
      "type": "number",
      "default": 0
    }
  },
  "required": [
    "state",
    "county"
  ]
}

The worst-rated bridges in a state (condition = Poor), ordered by lowest component rating then age. State is required. Use for 'worst bridges in X' questions.

{
  "type": "object",
  "properties": {
    "state": {
      "type": "string",
      "description": "US state postal code, e.g. 'IL'"
    },
    "limit": {
      "type": "number",
      "default": 50
    }
  },
  "required": [
    "state"
  ]
}

Bridges in a state that are load-posted or closed to traffic (NBI Item 41 status P/R/K), worst condition first. Relevant for routing and heavy-haul feasibility — but per FHWA, NBI data must not be used as the sole source for route clearance; inspections can be up to ~24 months old.

{
  "type": "object",
  "properties": {
    "state": {
      "type": "string",
      "description": "US state postal code, e.g. 'IL'"
    },
    "limit": {
      "type": "number",
      "default": 100
    },
    "offset": {
      "type": "number",
      "default": 0
    }
  },
  "required": [
    "state"
  ]
}

Bridges in a state whose vertical clearance is at or below max_height_m (or max_height_ft in feet — pass one, not both). Default clearance is over the roadway on the bridge (NBI Item 10); set under=true for the clearance under the bridge (Item 54B), which is what matters for routes passing beneath. Sentinel 'no restriction' values are excluded.

{
  "type": "object",
  "properties": {
    "state": {
      "type": "string",
      "description": "US state postal code, e.g. 'IL'"
    },
    "max_height_m": {
      "type": "number",
      "description": "Clearance threshold in meters, e.g. 4.0"
    },
    "max_height_ft": {
      "type": "number",
      "description": "Clearance threshold in feet, e.g. 14 — alternative to max_height_m"
    },
    "under": {
      "type": "boolean",
      "default": false
    },
    "limit": {
      "type": "number",
      "default": 100
    }
  },
  "required": [
    "state"
  ]
}

Bridge summary for one state: total bridges, counts by condition (Good/Fair/Poor), posted and closed counts, scour-critical count, average year built, total deck area. Without a state, returns per-state totals with condition counts for all states.

{
  "type": "object",
  "properties": {
    "state": {
      "type": "string",
      "description": "US state postal code, e.g. 'IL'"
    }
  }
}

Per-county bridge counts for a state, with Poor-condition and posted/closed counts per county.

{
  "type": "object",
  "properties": {
    "state": {
      "type": "string",
      "description": "US state postal code, e.g. 'IL'"
    }
  },
  "required": [
    "state"
  ]
}

Bridges near a point, nearest first. Pass lat/lon in decimal degrees; radius_km defaults to 10 (max 500). Each returned bridge carries distance_km. Bridges with no coordinates are excluded. Unlike the state-scoped tools, this one takes no state — the point is the scope.

{
  "type": "object",
  "properties": {
    "lat": {
      "type": "number",
      "description": "Latitude in decimal degrees, -90 to 90"
    },
    "lon": {
      "type": "number",
      "description": "Longitude in decimal degrees, -180 to 180"
    },
    "radius_km": {
      "type": "number",
      "default": 10,
      "description": "Search radius in km, greater than 0 and at most 500"
    },
    "limit": {
      "type": "number",
      "default": 100
    }
  },
  "required": [
    "lat",
    "lon"
  ]
}