Route One ELD uses engine ECM odometer data as the primary mileage source. GPS is used separately to attribute miles to the correct jurisdiction (state/province) for IFTA reporting.
Route One ELD records mileage using data from the vehicle's engine ECM (Engine Control Module) as the primary source, with GPS as a secondary reference for jurisdiction attribution. This is consistent with FMCSA ELD technical requirements, which specify that odometer readings be sourced from the engine where available.
Engine ECM Mileage
The ELD connects to the vehicle's engine through the diagnostic port (OBD-II or 9-pin connector) and reads odometer data directly from the ECM. This is the most accurate mileage source because it reflects the same data the vehicle itself uses — it cannot be affected by GPS signal loss or satellite interference. Engine odometer data is FMCSA-preferred for ELD mileage recording because it is tamper-resistant and consistent.
GPS and Jurisdiction Attribution
GPS tracking provides a geographic reference for where miles were driven — specifically, which state or province each segment of the trip falls into. For IFTA purposes, GPS coordinates are used to assign miles to the correct jurisdiction, not to measure total distance.
How They Work Together
- **Total miles driven**: sourced from the engine ECM odometer. - **Jurisdiction breakdown** (which state/province each mile was driven in): determined using GPS coordinates recorded during the trip.
This combination produces the per-jurisdiction mileage breakdown that IFTA returns require.
If GPS Was Unavailable
If GPS signal was lost during part of a trip, the ELD continues recording odometer mileage from the engine. Jurisdiction attribution for that segment may require manual review. See what setup is required for accurate IFTA data collection to minimize data gaps.