The fall in available business credit will limit the take-up of longer semi-trailers, even if the government approves their use, according to the Road Haulage Association (RHA).
Because the credit crunch has cut bank lending it will make investment in these trailers by smaller hauliers very difficult, says Ray Engley, head of technical services with the RHA.
He adds: "People won't be able to invest in [longer semi-trailers] because the banks won't let them, even though they could be a way of reducing CO2."
DHL says it hopes to be able to conduct off-road trials of longer trailers within the next six months. The logistics giant is part of the Iveco-sponsored UK steering group for longer semi-trailers, along with trailer-maker Montracon, the FTA and operators Chamberlain Transport and DHL.
DHL is a long-standing advocate of both longer, heavier vehicles (LHVs) and longer semi-trailers. David Potter, the firm's engineering director, says that he would hope to be able to conduct off-highway trials of a 15m-long trailer within the next six months.
While he insists it is too early to speculate on the precise efficiency gains offered, he does believe they are a viable proposition.
He says: "I certainly think there's value in longer trailers. In very simplistic terms, you are going to be able to increase pallet spaces by two over the current 24. For certain parts of our business, that's quite an impact.
"We believe from a transport point of view they will give us efficiency gains, but we need to work out their potential impact on our depots and other infrastructure."
He says a 15m trailer would be his preference because it keeps within the turning circle regulations without the need for a steering axle.
Potter says DHL is looking to work with trailer firm Don-Bur to develop the project; he wants to conduct track-based trials and then work towards on-road testing with DfT approval.