Carbon Footprint Comparative Survey: Cars with trailers frequently more climate-friendly than vans
Total emissions of cars with trailers are lower than those of vans without trailers in the majority of scenarios examined.
Berlin Dresden (16 October 2025). Fraunhofer IWU is currently conducting a carbon-footprint comparative survey examining the CO₂ balances of various road transport systems. A passenger car with two types of trailer is being compared with a van without a trailer. The study covers the entire life cycle. The results demonstrate that the combination of a car and trailer results in lower emissions than a 3.5-tonne van in almost all the scenarios considered.
Trailers and vehicles
For the manufacturing phase of the two trailer types, a Product Carbon Footprint (PCF) was calculated in accordance with ISO 14067:2018 and the GHG Protocol. Specifically, the study examined a flatbed trailer and a box trailer manufactured by STEMA Metalleichtbau GmbH. The cradle-to-gate analysis covers the period from the extraction of raw materials to the factory gate and it is based on primary data from 2023/2024, including high-quality foreground data (PCF data from in-house processes). Due to uncertainties in the quality of the background data (secondary data from databases for upstream and downstream processes), particularly concerning the sandwich material used in the box body, a safety factor of 20% was applied. Under these assumptions, the PCF results for the two trailer types amount to approximately 880 kg CO₂eq for the flatbed trailer and 2,337 kg CO₂eq for the box trailer.
For the vehicle configurations a VW Passat a VW Passat was chosen for the car-with-trailer version, and a Mercedes-Benz Sprinter 3,5 t for the van version. Life cycle data were sourced from the Green NCAP. website, which also enables comparisons between vehicles concerning their greenhouse gas emissions across the full life cycle.
Usage phase
An Excel tool was developed for the usage phase, that links Green NCAP life cycle data with real-world usage profiles (e.g. the annual mileage, transported payload, frequency of use, and trailer air resistance) to model various scenarios. In addition, due to the complex speed-dependent effects, an average speed of 80 km/h was used to simplify the calculations.
Results
The findings of the survey indicate that the total emissions of the “car with trailer” variants are lower in most of the scenarios examined than those of the “van without a trailer” variant. The key influencing factors on the CO₂ balance are the mileage driven, air resistance, and trailer usage frequency. The transported payload on the other hand plays a lesser role.
Where both the air resistance and trailer usage frequency increase, the van becomes more advantageous compared to the car with a box trailer. In urban traffic, however, where air resistance is less significant, trailer use is expected to have a very positive effect on the CO₂ balance.
Conclusion:
By way of a summary, the Carbon Footprint Comparison Study demonstrates that the combination of a car and trailer represents the more sustainable alternative in many scenarios. This applies especially in those cases where flexibility is required and no regular transport of heavy or bulky goods is necessary. The advantages include lower emissions during the manufacturing phase as well as reduced energy consumption when driving without a trailer.
In addition, trailers offer ecological and practical benefits that go beyond mere emission balances:
- Lower speeds when towing (maximum 80 km/h or 100 km/h) reduce fuel consumption levels by 20–40%.
- Differences in maintenance and recycling: Lower consumption of lubricants, tyres and other expendable parts, and a higher recycling rate for trailers compared with vehicles.
- Increased flexibility:
- Wide range of trailers for different applications.
- Trailers can be parked while the towing vehicle is being used for other purposes.
- Trailers that are temporarily not being used can be used as additional, cost-effective storage space.
By way of a conclusion, it should be noted that the results of the survey are subject to some elements of uncertainty. During the usage phase, in particular, much of the data is based on estimates, and complex interrelationships have been simplified. For this reason, further investigations into speed, the route profile and specific applications are recommended.
The study was commissioned by the Trailer Industry Association (TIV).
The TIV represents 39 manufacturers of trailers with a total mass of up to 3,500 kg and suppliers from ten European countries: Germany (17), Netherlands (5), Belgium (4), France (4), United Kingdom (2), Poland (2), Czech Republic (2), Austria (1), Romania (1), Slovenia (1).
For the correctness of the copy: Martin Zumpe / Tobias Blaurock
Trailer Industry Association TIV: Board Member Gunnar Bregler (UNITRAILER Holding), Chairman of the Executive Board Michael Jursch (STEMA Der Anhänger), Chief Representative Karlheinz Spägele (formerly AL-KO Vehicle Technology), and Executive Board Member Henk Sturme (Drotech BV).
The survey was conducted by:
Fraunhofer Institute for Machine Tools and Forming Technology IWU
Factory System Design and Production Planning
Contacts:
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Martin Zumpe (M. Eng.), martin.zumpe@iwu.fraunhofer.de, phone number: +49 351 4772-2438
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Maximilian Stange (M. Sc.), maximilian.stange@iwu.fraunhofer.de, phone number: +49 371 5397-1820
