32 meters long, two standard semi-trailers and only one tractor: With EcoDuo, German and Spanish companies aim to make road freight transport more efficient and climate-friendly. After a year of field testing between Wolfsburg, Lehrte and Barcelona, the project consortium reports a positive balance — and now calls for political decisions to enable regular operation.
A pilot project with signaling impact
In September 2024, the German Association of the Automotive Industry (VDA), Schmitz Cargobull, the Spanish logistics company Sesé, Kombiverkehr, Volkswagen Group Logistics and TÜV Rheinland launched the pilot project in Lower Saxony. Since then, the EcoDuo vehicle combinations have carried out regular round trips to Barcelona and back for a year, according to the companies. The aim, according to the joint statement, was to test the everyday practicality of the unusually long articulated combinations in the pre- and post-haul of intermodal transport and to gain experience for a possible regular operation.
The EcoDuo consists of two standard semi-trailers connected to each other via a dolly, and hauled by only one tractor. The total length is 31.70 meters, the permissible gross vehicle weight is 40 tonnes, and in intermodal transport 44 tonnes. Thanks to ten axles, axle loads remain below the applicable limits. For the pilot operation, exemptions were granted under § 70 StVZO and § 29(3) StVO.
Seamless connection to
the rail
One crucial finding from the trial: The EcoDuo can be loaded onto the rail without any extra effort. According to the consortium's statement, the two semi-trailers simply need to be decoupled before loading and reconnected after unloading. No additional technical adjustments are necessary. However, handling terminals require sufficient space for maneuvering and pre-staging, as well as adequately dimensioned maneuvering zones.
According to the project officials, the challenge is less about yard maneuvering on site, and more about whether the EcoDuo combinations can enter and exit the terminals as a whole. Where this is not possible, they would need to be coupled or decoupled before entering the terminal.
During the test phase, the terminal operators handled the dolly themselves: they parked it on the site and reused it in the next cycle. This solution was pragmatic but should be evaluated organizationally depending on the location.
"The results of the pilot project demonstrate convincingly that the concept can be seamlessly integrated into existing structures and is convincing both ecologically and economically," summarizes VDA Managing Director Andreas Rade.
Efficiency, climate protection and driver shortage
The project team points to several advantages. By carrying two standard trailers with a single tractor, transport capacity per trip increases, reducing trips and thus emissions. At the same time, freight forwarders could mitigate the acute driver shortage
because fewer drivers are needed for the same transport volume.
The combination is particularly suitable for high-volume transports, such as plastic parts for automotive production, textiles, or parcels. The payload is currently a maximum of nine tonnes per trailer because the permissible gross vehicle weight in Germany is limited to 44 tonnes. According to project partners, technically significantly higher weights could be realized, but current legislation restricts this.
Compared to previous long-truck concepts, the EcoDuo is intermodal-capable, the partners emphasize. While conventional long trucks cannot easily be loaded onto the rail, the EcoDuo trailers meet the usual requirements for intermodal transport.
Legal hurdles for regular operation
To enable operation in everyday conditions, statutory provisions must be adjusted. According to the consortium, the regulation on exemptions from traffic regulations for vehicles and vehicle combinations with overlength should be expanded with a new vehicle type "Type 6." This would allow truck-trailer combinations up to 32 meters in length to operate on a specially designated network. This network should primarily include intermodal transport locations and thus ensure integration into existing transport chains.
The project partners see the EcoDuo primarily in hub-to-hub traffic and in the inbound and outbound flows of intermodal transport. They do not see concerns about operational safety. The EcoDuo fulfils all technical standards, including the requirements for long trucks, and does
not exceed axle loads or total weights.
The industry is also looking abroad: In Spain there are already around 1,000 EcoDuo vehicles in operation, and they are also in use in Scandinavia. There, higher permissible gross weights apply, which makes operation economically more attractive. How deployment in Germany will develop is not yet foreseeable, according to the project leads.
Outlook for the industry
After completion of the scientific evaluation by TÜV Rheinland, the participants intend to obtain regular approval for EcoDuo in Germany. In Spain and Scandinavia, the concept is already established. For logistics companies, this opens the chance to move more load volume per vehicle, reduce CO2 emissions, and better utilize scarce driver resources.
However, much depends on future weight regulations. The project partners emphasise that the current limit of 44 tonnes restricts deployment options. Higher permissible gross weights could significantly increase the economic significance of the concept.
The coming months are likely to show whether policymakers and authorities create the legal framework for the new vehicle type. For freight forwarders and fleet managers, this could mean getting early involved in route planning, terminal logistics, and driver scheduling to prepare for the possible deployment of such combinations. Those active in intermodal transport could particularly benefit from the EcoDuo — provided the infrastructure is adjusted and the legal hurdles are removed.
