CO2 Methodology
This page explains how ecoTriver calculates CO2 emission reductions from shared rides. Our methodology is transparent, conservative, and based on government-published emission factors.
What We Calculate
When passengers share a ride to an event instead of each driving their own car, fewer vehicles are on the road. ecoTriver quantifies this benefit as CO2 saved: the emissions avoided because matched passengers did not drive alone. ecoTriver collects no climate contribution today.
Methodology Framework
Our CO2 calculation methodology is being developed in alignment with GCCM007, the Global Carbon Council's Methodology for Private Carpooling for Long-Distance Inter-Urban Travel.
Note: ecoTriver does not claim GCCM007 certification or third-party verified emission reductions at this stage. We are documenting our methodology to the standard's requirements as preparation for future external verification.
How CO2 Savings Are Calculated
The baseline assumption is simple: without the carpooling platform, each matched passenger would have driven to the event alone in their own car. The emission reduction is the difference.
CO2 saved = distance (km) × emission factor (kg/km) × passengers matched
Example
A one-way ride of 200 km with 2 matched passengers:
200 km × 0.164 kg/km × 2 passengers = 65.6 kg CO2 saved
For round trips, both legs are counted, since the return journey also avoids solo driving:
(200 × 2) km × 0.164 kg/km × 2 passengers = 131.2 kg CO2 saved
Distance Calculation
Distances are calculated server-side using the haversine formula (great-circle distance) between the ride origin and the event venue. This produces straight-line distances that are 20-40% shorter than actual road distances, a deliberately conservative choice.
Venues pinned to an official house coordinate: Geodaten Sachsen, dl-de/by-2-0, dataset, converted to latitude and longitude. Swiss addresses: Federal Office of Topography swisstopo. US addresses: US Census Geocoder. Toronto addresses: contains information licensed under the Open Government Licence (Toronto).
Emission Factors
Booked car rides and declared solo car trips are calculated with the UBA car factor in every country. For the other modes, country-specific factors apply where available (Germany: UBA); elsewhere the DEFRA/DESNZ conversion factors are used as the internationally recognised default, consistent with GHG Protocol guidance.
| Country | Source | Car Factor | Unit |
|---|---|---|---|
| Germany | UBA, TREMOD 6.71B (2024) | 0.164 kg/km | CO2e |
| United Kingdom | UBA, TREMOD 6.71B (2024) for booked and solo car trips; DEFRA/DESNZ (2024) for coach, rail, public transport and carpool; DEFRA/DESNZ for flight (source year not recorded) | 0.164 kg/km | CO2e |
| All other countries | UBA, TREMOD 6.71B (2024) for booked and solo car trips; DEFRA/DESNZ (2024) for coach, rail, public transport and carpool; DEFRA/DESNZ for flight (source year not recorded) | 0.164 kg/km | CO2e |
UBA = German Federal Environment Agency. DEFRA = UK Department for Environment, Food & Rural Affairs. CO2e includes methane and nitrous oxide alongside CO2. The UBA factors include the supply of fuel and electricity (well-to-wheel); the DEFRA/DESNZ factors are direct emissions only (tank-to-wheel), with the supply share published separately by DEFRA. Factors are reviewed annually.
Conservative Assumptions
Where there is uncertainty, we err on the side of understating emission reductions:
- Straight-line distance: haversine distances are 20-40% shorter than actual road routes, reducing our claimed reductions.
- Average fleet factor: includes electric vehicles in the fleet mix, which lowers the average emission factor.
- No access/egress segments: only the main ride distance is counted. Travel to the pickup point and from the drop-off to the final destination is excluded.
- Cancelled rides excluded: only rides with confirmed bookings contribute to impact metrics.
Data Quality & Transparency
All CO2 and distance values are calculated server-side. Users cannot manually set or modify emission data. Key safeguards:
- Distances computed via PostGIS geographic functions, immune to client-side manipulation
- CO2 values derived from validated distance and published emission factors
- Input validation on all ride parameters before processing
- Database constraints enforce data integrity (foreign keys, type constraints)
- All calculation logic and emission factors are version-controlled and auditable
Limitations & Uncertainty
No emission calculation is exact. We disclose our known uncertainty sources so that our numbers can be assessed in context.
| Source | Range | Direction |
|---|---|---|
| Distance (haversine vs. road) | −20% to −40% | Conservative understatement |
| Emission factor vs. actual vehicle | ±15% | Symmetric |
| Baseline assumption (solo driving) | +0% to +29% | Potential overstatement |
| Aggregate annual claims | ±25% | Net (conservative bias) |
Our reported numbers are more likely to understate than overstate actual emission reductions, due to the systematic conservative bias from haversine distance calculation. Full uncertainty analysis is documented in Section 7A of our methodology document.
Version History
March 4, 2026
Initial formalized methodology with EU Directive 2024/825 terminology compliance. Terminology updated from "compensation" to "climate contribution" across all user-facing materials.
July 11, 2026
Added the gross attendee-travel Scope 3 inventory (per-vehicle car factor EF_CAR_KG_PER_VKM = 0.230 kg/vkm; distance-based GHG Protocol method; intent round-trip assumption; primary-vs-estimated split). The avoided-emissions ("CO2 saved") and climate-contribution figures are annexes and are never netted against the gross inventory. Introduced the value-chain-ready Scope 3 data package (export schema v1.0).
October 12, 2026
Corrected a counting error in the gross attendee-travel inventory: persons are counted once per event across linked ride legs. A round trip stored as two one-way rides had counted its driver and passengers twice, which doubled the measured sample and its coverage and halved the extrapolated total. Gross emissions and passenger-km are unchanged.
October 12, 2026
Corrected a counting error in the people-connected figure of the organiser console, the event archive and the evidence-pack export: persons are counted once per event across linked ride legs, by the same rule as the gross attendee-travel inventory. A round trip stored as two one-way rides had counted its driver and passengers twice. The driver of a coach counts once per coach. CO2 saved, kilometres and the gross inventory are unchanged.
October 12, 2026
Club attribution in the organisation report, the evidence pack and the Scope 3 package: a club whose team link is confirmed now reports that team's home and away games. On these games a ride counts for the club whose team chip it carries, a neutral ride half for each club, a coach for the club that runs it. Where both clubs of a game have linked their team, every ride counts once across the two and their totals add up to the game total, up to 0.1 kg of rounding per share. A person counts once per game, at the mean share of the rides they took; a declared travel intent counts at the neutral share. Only the club that owns a game extrapolates it, and only its own share, with the coverage of the whole game. Also corrected: on a game a club owned and played in, a ride with the opponent's chip or without a chip had counted in full for the owner as well. The console's travel report card and the impact widget for your website follow both changes. Organisations without a confirmed team link are unchanged.
October 30, 2026
Corrected a counting error in CO2 saved: a booking that rides only the way back of a round trip saves one of its two legs, not both. A seat on the way back only now counts half of the round trip's per-passenger figure, and the reduction baseline of the organiser reports holds that passenger on one leg and the driver on both. The passenger-km of the Scope 3 inventory follow the same rule, and with them the gross CO2 of coach, rail and flight rows; a car's gross CO2 is per vehicle and does not move. A passenger on the way back only still counts as one person. These keep the earlier figure until a later version: every figure summed from the event archive (the archive itself, the impact cards and trace lines on artist, tour, club, league, label, organiser, venue and series pages, the impact ledger on the statistics page and the sports clubs page for sustainability managers; the city pages already follow the new rule), and the driver's CO2 in the driver block on the ride page and in the driver panel of ride rows. On 30 October 2026 no confirmed booking outside the demo data rode the way back only, so no published figure changes.
Full Methodology Document
This page provides a summary of our approach. The full methodology document includes detailed formulas, a GCCM007 gap analysis, monitoring plan, and emission factor source documentation.
For the complete methodology document, emission factor sources, or verification inquiries, please contact us at ….
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Methodology: common questions
The emission factor, the calculation method, and how updates are handled.