Question to the Department for Transport:

To ask the Secretary of State for Transport, with reference to the evaluation of the longer semi-trailer trial: annual report 2015, published in August 2016, what roads are being used by longer semi-trailers; and what the mileage is of such trailers on minor and urban roads.

The original trial terms of reference and operator undertaking issued in 2011 did not place a requirement on participating companies to track the exact movements of each Longer Semi Trailer (LST) or to log routes taken. When the trial started in 2012 GPS tracking was a new technology and to have placed such a tracking requirement on the operators would have been considered an unreasonable burden on the industry and would probably have excluded smaller operators from participating, limiting the coverage and value of the trial.

The expectation across the industry has always been that compared with other long articulated HGVs, LSTs would be likely to operate a greater proportion of their journeys on major roads, performing trunking duties. This is supported by the leg type use charts in the Annual Report, but is not ‘proven’.

During 2015, DfT and Risk Solutions looked into the options for studying LST routing by road types including sampling of the part of the fleet that is fitted with trailer GPS, backfitting the entire fleet (or those not currently fitted) with trailer GPS, or modelling the ‘likely’ routing of LSTs using the origin and destination data already provided in the trial data submissions. Modelling the likely route was chosen because it would effectively provide an insight into the balance of road types used by LSTs at a reasonable cost to the taxpayer, while minimising the additional burden on the industry.

After a feasibility study in late 2015, the trial data requirement was adjusted to make journey start/end postcodes a requested item for 2016-P1 (Jan-May) and mandatory thereafter. Operators have responded well to this requirement and Risk Solutions have start/end postcode data for more than 90% of all LST journeys) to date in 2016.