HGV Emissions Modelling for a Strategic Logistics Park

The Project

A logistics developer was promoting a strategic distribution park on a former employment land allocation in the East Midlands. The site had capacity, on the indicative masterplan, for around 1.2 million sq ft of B8 floorspace and a peak operational profile of approximately 1,200 HGV movements per day across the access network. Air quality was identified at scoping as one of the principal environmental topics requiring detailed assessment within the Environmental Statement.

The site lay close to a primary school (200m from the proposed access junction) and a small village whose residents had organised a local objector group. Air quality was, predictably, one of the headline issues raised during the pre-application consultation.

The Challenge

The local planning authority's environmental health team requested a detailed dispersion modelling study covering the local highway network, with proper verification against measured concentrations. They also requested that the assessment quantify the cumulative effect of this scheme alongside other consented and emerging logistics development in the wider area — a reasonable request given the cluster of similar proposals coming forward at the time.

A standard background-mapping screening assessment would not be sufficient. The receptors were too close, the traffic generation was too significant and the local political context required defensible technical work that would withstand objector and statutory consultee scrutiny right through to committee and, if needed, an inquiry.

Our Approach

We deployed a bespoke diffusion tube monitoring network at six locations across the site and surrounding receptors, running for six months prior to the modelling phase. The data provided a properly anchored verification dataset and demonstrated to the LPA that the assessment was based on local, measured air quality rather than only on Defra's national background maps.

The dispersion modelling itself was carried out using ADMS-Roads, with the local highway network coded in detail including traffic flows, fleet composition (with bespoke HGV percentages from the transport assessment rather than generic defaults) and queue locations at the principal junctions. Future-year scenarios were modelled at year of opening and at 10 years post-opening, with cumulative scenarios incorporating committed development from the LPA's commitments register.

On the operational mitigation side we tested and documented a layered strategy. EV-capable HGV charging infrastructure was committed at 15% of bays from year one of operation, scaling to 100% by year ten, recognising the trajectory of HGV electrification through the late 2020s and 2030s. Staff EV charging was committed at 1:1 ratio of parking bays. Idling reduction protocols at the loading docks were specified, with site-management responsibility built in. We also drafted a graduated tenant emission standards covenant: tenants signing leases in years 1–3 would be required to operate Euro VI fleets, with a transition to mandatory zero-emission tractor units for new leases from year 7 onwards.

The verified, mitigated assessment showed that the operational scheme would not cause an exceedance of any air quality objective at any sensitive receptor, and that the magnitude of impact at all relevant locations was negligible to small in IAQM terms. The cumulative scenario, including other regional logistics development, gave the same conclusion.

The Outcome

The air quality chapter was accepted by the borough's environmental health team and by statutory consultees with no significant outstanding objections. The application was reported to planning committee with an officer recommendation for approval, and a resolution to grant was secured. The mitigation strategy — in particular the graduated EV transition obligations on tenants — was adopted as a Section 106 planning obligation with reporting milestones tied to the build-out programme.