The article discusses the potential of retrofitting heavy transportation vehicles with hydrogen technology to decarbonize the transport sector. It highlights the growing adoption of clean mobility solutions like hydrogen vehicles as an alternative to fossil fuel combustion engines. The focus is on retrofitting long-haul heavy trucks, buses, and vans with hydrogen powertrain to reduce carbon emissions. While the upfront costs of new hydrogen trucks and buses pose a barrier, retrofitting existing vehicles is seen as a competitive and environmentally advantageous solution. Retrofitted vehicles benefit from using existing vehicle bodies and accessories, reducing overall costs and receiving subsidies in European countries. The article emphasizes the need and opportunity for retrofitting in Europe, where a large fleet of predominantly fossil-fuel-powered trucks, buses, and vans would take decades to replace with new clean vehicles. Retrofitting is identified as a feasible candidate for decarbonization with clear economic, technical, and environmental advantages. The market dynamics include both established manufacturers and new entrants offering hydrogen solutions, with startups like ULEMCo in the UK leading with innovative technologies. Despite challenges like low deployment of hydrogen vehicles, retrofitting is viewed positively as a pathway to efficiently decarbonize the transport sector.