Question to the Department for Transport:

To ask the Secretary of State for Transport, if she will model the potential impact of (a) single 32 tonne drum mixers against (b) 38.4 tonne volumetric concrete mixers on bridges.

On 18 March 2025 the Department published a National Highways commissioned study on the load impacts of volumetric concrete mixers on bridges alongside the outcome of a call for evidence that ran in October-December 2023. This can be found at the following link: https://www.gov.uk/government/calls-for-evidence/volumetric-concrete-mixers-review

The report compared the forces exerted by higher weight VCMs to the standard model used for assessing bridges and found the load effects from these VCMs to be up to 17% higher than those complying with weight limits. This would put significant strain on existing bridges. 32 tonne drum mixers operate within the assessment load models.