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Your auditor wants source-level emissions data. Your fuel receipts aren't going to cut it.
For fleet operators subject to the EU's Corporate Sustainability Reporting Directive (CSRD), this is becoming the central compliance problem. Estimations built from fuel card transactions, manual mileage logs, or aftermarket telematics devices are increasingly hard to defend under audit. CSRD doesn't just require emissions numbers, it requires you to demonstrate the methodology behind them. And "we estimated based on distance travelled" is a methodology that's running out of road.
OEM vehicle data solves this in a way nothing else currently does.
The problem with how most fleets measure emissions today
The typical fleet emissions workflow looks something like this: collect fuel receipts at the end of the month, multiply litres by a standard emission factor, add it to a spreadsheet, hand it to the sustainability team. For electric vehicles, the calculation is even rougher — often estimated from charging invoices or odometer readings.
The result is emissions data that is delayed, inconsistent, and difficult to audit. For CSRD reporting, that's a serious liability. The directive increasingly expects businesses to show not just what their emissions are, but how they know — with auditable, source-level data that can withstand scrutiny.
Most fleets aren't there yet. The ones that will be are building on direct vehicle data.
What OEM data actually gives you
When you access data directly from the vehicle manufacturer — through the OEM's official API rather than a third-party device — you get a fundamentally different quality of information.
Take a concrete example. A BMW van in your fleet completes a 180km delivery run. With a fuel card, you know it was refuelled on Tuesday with 42 litres of diesel. With OEM data, you know the actual fuel consumed on each trip, whether any fault codes are present, and the cumulative mileage for the week. That's the difference between an estimate and a measurement.
For CSRD purposes, this translates directly into more defensible reporting:
Scope 1 emissions (direct fleet emissions from ICE vehicles) can be calculated from actual fuel consumption per vehicle, per trip — not from receipts that may lag by weeks or cover multiple fill-ups across different vehicles.
Scope 2 emissions (electricity consumed by EVs) can be tracked through real charging data: energy drawn per session, time of charge, location. This matters because grid emission factors vary significantly by country, time of day, and energy mix — and accurate Scope 2 reporting requires knowing exactly when and where charging happened, not just how many kWh appeared on an invoice.
Operational emissions reduction — which CSRD increasingly expects alongside disclosure — becomes actionable when you have per-vehicle, per-trip insight. Excessive idling, aggressive acceleration, inefficient routing, underutilised vehicles sitting charged and depreciating: all of this becomes visible and addressable.
The EV reporting gap nobody's talking about
Electric fleets present a particular challenge for CSRD reporting, and it's one that's rarely discussed directly.
The assumption is that EVs simplify emissions reporting — zero tailpipe emissions, done. In practice, Scope 2 accounting for large EV fleets is more complex than it looks. Charging happens at different locations (depot, public charger, driver's home), at different times, across different grid regions with different carbon intensities. An EV charged from a renewable depot tariff in the Netherlands has a very different emissions profile from one charged overnight at a motorway charger in Poland.
Without direct vehicle data, none of this is visible. You're back to estimates.
OEM data for EVs includes battery state of charge, energy consumption per trip, charging session data, and in many cases the location and duration of charging events. This gives sustainability teams what they actually need: a per-vehicle energy ledger they can map to real grid emission factors, rather than a fleet-wide kWh estimate divided by vehicle count.
The mixed fleet problem
Most enterprise fleets aren't single-brand. They run BMWs alongside Toyotas, Renaults next to Mercedes — a mix that reflects procurement decisions made over years across different regions and business units.
Each of those OEMs operates within its own data ecosystem. Accessing emissions data from each one separately means managing multiple API integrations, different data formats, inconsistent update frequencies, and separate consent and authentication flows. For a sustainability team trying to produce a unified CSRD report, that's an enormous amount of operational complexity before you even get to the analysis.
A unified vehicle data platform changes this equation. Instead of building and maintaining OEM-by-OEM integrations, fleet operators can access normalised data from multiple manufacturers through a single API — same format, same update cadence, same data model regardless of the brand.
Where High Mobility fits in
High Mobility provides exactly this: a single API layer contracted directly with many OEMs — including BMW, Mercedes-Benz, Toyota, Volkswagen Group, Renault, Nissan, and others — that normalises their vehicle data into a consistent, harmonised format.
For CSRD-focused fleet operators, that means:
- Actual fuel consumption and idling data per vehicle, not estimates
- EV charging and energy consumption data at session level
- Mileage, trip history, and driving behaviour across mixed-brand fleets
- A single integration that covers your entire fleet, regardless of manufacturer
- Data delivered in real time, not batched weekly from a portal export
High Mobility's data pipeline processes over 100 million data point updates daily. That scale means the infrastructure is already built for enterprise fleet requirements, not something you're testing at the proof-of-concept stage.
What this means in practice
CSRD compliance has a deadline, and auditors are getting more specific about what they'll accept. Fleets that arrive at their first mandatory reporting cycle with spreadsheet estimates built on fuel receipts are going to have a harder conversation than those with auditable, source-level OEM data behind their numbers.
Beyond compliance, there's a real operational argument too. The same data that supports your emissions report also tells you which drivers are burning 15% more fuel than the fleet average, which vehicles are idling for two hours a day at depot, and which EVs are being charged on expensive peak-rate public chargers when depot charging is available. Reporting and optimisation come from the same source.
For fleets working toward CSRD compliance — particularly those managing mixed-brand, multi-region operations — OEM vehicle data isn't a future consideration. It's the foundation the reporting needs to stand on.
