On the Commercial Motor site there is extensive list of hauliers who have applied to take part in the trials for the longer trailers. If the trial does not go forward these hauliers can still use the trailers after the trial ends. However it begs the question that if a 13.5m is usually grossed out what are you carrying that would benefit an extra metre space in the trailer? At RDCs one usually sees trailer with space on anyway - 20/22 pallets tinned food, drinks, frozen products; elsewhere paper, timber, cement etc, etc. The trend for biomas products, also aggregates would not benefit from longer trailers. If hauliers/own account ops are carrying light goods they usually have taller trailers so maybe this will pre-empt the 4.0m hight limit that Brussels is keen to introduce. 
The contents of 52 pallets of plastic bottle tops weigh less than the pallets themselves, there are many items that could be loaded on longer trailers. The down side is that if you are on general haulage you would just carry more fresh air around at times.
The main operators that would gain would be the own account or dedicated fleet ones that carry light goods at all times.
Pharmaceuticals, Domestic appliances, Parcels, Packaging, Insuation, Snack foods…
The list is endless. Transport doesn’t begin and end at the RDC you know 
billybigrig:
Pharmaceuticals, Domestic appliances, Parcels, Packaging, Insuation, Snack foods…The list is endless. Transport doesn’t begin and end at the RDC you know
WHAT?!! I won’t sleep tonight now wondering what I’ve been missing all this time!! 
Its OK if you load Full,but running half Full most of Time,or running in weight Difficulty makes no sence buying longer Trailers you also gettin in Trouble at some of your Way
roadhog69:
However it begs the question that if a 13.5m is usually grossed out…
The majority of trailers on the road at any one time will not be running at full weight, or even close to it. I don’t think a trailer ever leaves our place anywhere near gross weight.
I can see these trailers being well suited to the pallet networks and contract/own account hauliers.
We run 18 Mtrs 6 + 12 link combinations: Combination can carry 34/35 tons (11 on the front 6 and 23/34 on the back 12m) and a standard 12mtr Tri axle can carry 28 tons, so you only gain 6 tons carrying capacity but with 50% more space, trust me when I say, that space is very useful indeed, mix cargo 20 Plts Tinned with 10 Plts Toilet rolls etc etc
i wait with anticipation when some muppet tries to go to a place like hawes and gets stuck in town centre
To operate between two points close to motorway junctions would probably present no problems, but operators will not be content with that, they will want to use them anywhere no matter how unsuitable the roads are.
Time will tell as it always does.
i saw one of these trailers the other day on a bay at the Co-op at Coventry Pro-Logis Park, there wasnt a unit on the front, there was an Axor with a 45ft trailer next to it, the front of the longer trailer was level with the door handle and the back of the passenger door window on the Axor.