What HCV mean can differ from country to country. In UK and Germany as far as I know they consider 25.25 m B-double as HCV when current official length is 18.75 m (40/44 ton Germany), but for Sweden current official length is 25,25 m (module, not module 24 m) and 64 ton. Soon Sweden will icrease max weight to 74 ton and it is already a road net which is permitting this. So the definition of HCV are different, what was HCV yesterday are standard today (Sweden). Sweden and Finland are testing HCV:s around 90 tons and a little bit more than 30 m length.
Reason behind this HCV projekts in Sweden an Finland is that both countries are dependent forest and mining industries which huge cargo volumes.
https://www.youtube.com/watch?v=qs9W5mgzStk
Since several years in Germany it is an A-double which Hamburg - Lübeck connecting the two ports. I don't know if the weight is more than 44 ton.
