Question to the Department for Transport:

To ask the Secretary of State for Transport, if she will make a comparative assessment of the potential impact of (a) 44-tonne, five-axle volumetric concrete mixers and (b) traditional drum mixers on (i) the number of vehicle movements, (ii) road wear and (iii) water usage.

The Department has not made a specific comparative assessment of the potential impact of 44-tonne, five-axle volumetric concrete mixers (VCMs) and traditional drum mixers.

The Department estimates there are in the region of 1,000 VCMs in operation alongside 20,000 drum mixers. The report undertaken by National Highways as part of the Department’s review of VCMs compared the forces exerted by the VCMs to the standard highway vehicle load model used for assessing bridges and found the effects were up to 17% greater than for vehicles complying with the current standard weight limits. This will likely result in increased wear and tear and may impact the durability and lifespan of existing bridges. In addition to the impact on bridges, heavier vehicles also put more stress on roads.

The outcome of the Department’s review into VCMs, including the report by National Highways, was published on 18 March 2025. This can be found at the following link: https://www.gov.uk/government/calls-for-evidence/volumetric-concrete-mixers-review