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, in the API Commons Rate Limits shape.

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

Limit state is signalled in the limit, remaining, reset, and retryAfter response headers, and an exhausted limit returns HTTP 429.

This profile was written by API Evangelist and has not been verified against a page the provider published; treat every limit as unconfirmed until a dated transcription replaces it.

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 Exhausted: HTTP 429 Quota: 429 limitremainingresetretryAfter
Method: generated, dated 2026-05-05.
Written by API Evangelist on 2026-05-05 and not verified against a page the provider published. Treat every limit as unconfirmed until a dated transcription replaces it.
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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

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