The Department for Transport started to conduct trials of longer semi-trailers in January of this year. 1800 semi-trailers are involved in the trials.
900 semi-trailers involved in the trials are 1 metre longer than the current maximum. These new trailers, which are 14.6m in length, bring the total maximum length of the articulated vehicles to 17.5m.
A further 900 semi-trailers are 2.05m longer than normal, bringing the total articulated vehicle length to 18.55m.
The longer semi-trailers will still be required to operate at the existing 44 tonne weight limit for 6 axle vehicles though.
The trial intends to run for a minimum of 10 years, which should enable the voluntary participants in the scheme to recover the costs of their investments. The Department for Transport has not guaranteed that the use of longer semi-trailers will be permitted beyond the end of the trial period.
Independent monitoring of the scheme will take place by a strategic risk management company, Risk Solutions. They will monitor the impact of the longer semi-trailers on carbon emissions, lorry miles and accident rate, amongst other things.