Department of Transportation · Rate Limits

Department Of Transportation Rate Limits

DOT APIs split into two regimes. NHTSA Vehicle Safety (api.nhtsa.gov) is fronted by api.data.gov, which enforces a default 1,000-requests-per-hour limit per developer key (raisable via support). NHTSA vPIC, FMCSA QCMobile, FAA Airport Status, and the BTS / FRA / FTA / PHMSA open data portals are unauthenticated and bounded by fair-use rather than per-key quotas. api.data.gov surfaces 429 with X-RateLimit-* headers; open endpoints use standard server throttling.

Department Of Transportation Rate Limits is the machine-readable rate-limit profile for Department of Transportation on the APIs.io network, conforming to the API Commons Rate Limits specification.

It captures 3 rate-limit definitions, across the api-data-gov and open tiers, measuring requests_per_hour and requests_per_minute.

The profile also includes 5 backoff/retry policies defined and response codes documented for throttled, quotaExceeded, serviceUnavailable, and forbidden.

Tagged areas include Federal Government, Transportation, Vehicles, Aviation, and Motor Carriers.

3 Limits Throttle: 429 Quota: 429
Federal GovernmentTransportationVehiclesAviationMotor CarriersRate Limiting

Limits

api.data.gov default per-key limit api-key
requests_per_hour · hour
1000
api.data.gov increased limit (raise via support) api-key
requests_per_hour
higher; request via api.data.gov support
Open / fair-use throttle IP
requests_per_minute
fair-use; not published

Policies

api.data.gov Key Pattern
NHTSA Vehicle Safety endpoints enforce limits at the api.data.gov gateway. Excess returns 429 with a JSON error and an OVER_RATE_LIMIT code. Increases must be requested via api.data.gov support.
NHTSA vPIC Bulk Pattern
NHTSA vPIC publishes downloadable vehicle data CSV / database snapshots; bulk consumers should download the database refresh rather than iterate the REST API.
FAA Airport Status Cadence
Airport status data refreshes on a short cadence (minutes); avoid sub-minute polling since values change rarely outside weather and operational events.
Backoff Strategy
On 429 / 503 implement exponential backoff with jitter, honoring Retry-After when present.
Caching Encouragement
All DOT bureaus encourage caching of responses (vehicle data, airport status, motor-carrier records) to reduce load on shared infrastructure.

Sources