Concerns among operators migrating their longer semi-trailers (LSTs) over to new arrangements when the trial ends next week have still not been resolved, according to the RHA.

The government trial began in 2012 and results showed that the vehicles increased capacity by up to 15% compared to a single deck trailer and improved operational efficiency as well as environmental performance.

An extension was granted last year in order to reduce bureaucracy after companies complained that the new requirements to provide a route plan and a risk assessment for their LST routes was driving up costs and reducing efficiency.

However, the RHA said hauliers still faced individually risk assessing every route and drivers were also expected to hold copies of risk assessments and route plans.

It said some firms were now saying they would reduce LST usage from next month despite investing in the vehicles.

“We have continued collaborating with the industry and government and convened conversations with operators and department for transport (DfT) officials to work on making guidance clearer,” the RHA said in a statement.

DfT guidance on LST use stated that operators must demonstrate a route planning, risk assessment and feedback process that was proportionate to the scale of the operation and number of drivers and routes involved:

“They will also need to provide the variety – road types, locations – and complexity of the routes being used,” it said.

“You are legally required to keep copies of route plans and risk assessments for a route for two years, starting with the date the LST was last used on that route.

“You should retain these copies so DVSA or a traffic commissioner can review them, if needed.”

The trial ends on 29 February.