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Route deviation: +14% km, hidden fuel + AETR

When the driver deviates from plan, km can rise 14% — fuel + time + AETR window erodes. Planned vs actual polyline comparison.

Drone aerial: a curving European motorway at night under sodium lights — a single truck taking a different junction from plan.
Drone aerial: a curving European motorway at night under sodium lights — a single truck taking a different junction from plan.

When the driver deviates from plan, km can rise by +14%. Some deviation is forced (closed road, customer request); some is preventable (habit, old route, wrong nav).

Industry case: 100 trucks × 12,000 km/mo × €0.10/km × 14% = €16,800/mo of fuel + time loss.

Planned vs actual polyline

Lognari logs two polylines per trip:

  • Planned: From OSRM/Mapbox/Google Maps API at trip assignment
  • Actual: From telematics GPS points (1-minute resolution)

The delta:

TripPlanned kmActual kmΔTraffic?Preventable?
#58211,8401,852+0.7%No
#58232,1402,298+7.4%FireNo
#58271,6401,873+14.2%None🚩 Yes
#58319801,092+11.4%Driver choice🚩 Yes

Pattern analysis: same driver + same lane + recurring deviation → behaviour-change required.

Impact by fleet size

FleetMonthly extra kmAnnual impact
100 trucks168,000 extra km€200,000+
300 trucks504,000 extra km€600,000+
1,000 trucks1.68M extra km€2M+ + CO₂ report (560 t)

Driver coaching loop

The Lognari pattern report lands at the ops centre monthly:

  • Top 10 deviation-heavy drivers
  • Which lanes
  • Reason code (where given)
  • Action recommendation

Pilot fleets see deviation drop from 14% → 6% after a 90-day coaching program.

What’s next

If your fleet doesn’t run automatic per-trip km comparison, 14% deviation is likely there — a pilot makes that concrete.

Reach out via the contact section — reply within one business day.

Frequently asked

How are planned and actual routes compared?
Planned route fetched from OSRM/Mapbox API as a polyline. Actual route built from telematics GPS points. Hausdorff distance + km delta + time delta between the two polylines.
Does the driver get a 'don't deviate' message?
No. Deviations can be rational (queue, road closure, customer request). The system logs the deviation, captures a reason, runs pattern analysis — structural problem or one-off?
Where does the 14% figure come from?
Average EU fleet planned-vs-actual km delta is 12–16% (KPMG European Fleet Survey 2025). 60% of that deviation is preventable (non-traffic, non-customer).

Let's talk about your fleet

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