DMRB visibility on the A120 and costs against National Highways: the Marks Tey appeal.

The appeal

The site is a field with an existing concrete agricultural access onto Coggeshall Road, part of the A120 and the strategic road network (decision, paragraphs 9 and 10). The inspector described the road as exceptionally busy. It has a 40 mph limit and, as agreed in the transport statement of common ground, 85th percentile speeds of 33.6 to 35.9 mph. Visibility on exit was agreed as 120 metres to the left and 90 metres to the right, with the splay entirely within the public highway (paragraph 10). The main issue was the effect on highway safety and the road network (paragraph 8).

Which standard applied

The parties accepted that the Design Manual for Roads and Bridges was highly relevant to a trunk road, but agreed that the site, within a built-up area, was not typical of its application. Manual for Streets was more suited to the scale of the proposal, but less so to its context on the A120. Both were treated as technical guidance (paragraph 12).

Stopping sight distance and the splays

The inspector applied Table 2.10 of CD 109, recording 120 metres as the desirable minimum stopping sight distance and 90 metres as one step below, which matched the visibility available to the left and right. With reference to paragraph 3.5 of CD 123, which uses the 85th percentile speed for an existing major road, the inspector took the upper surveyed figure of 35.9 mph and found that the distances could be reduced to 90 metres desirable and 70 metres one step below, achievable in both directions (paragraph 13). The existing splays were therefore in accordance with DMRB (paragraph 14).

No condition was imposed for the splays. As the visibility lay entirely within the public highway, maintaining it was the highway authority's responsibility and beyond the appellant's control, so such a condition would fail the tests of reasonableness and enforceability (paragraph 36). Conditions instead required gates set 14 metres back and kept that area free of new enclosures, so that the longest legal vehicle and trailer could pull clear of the carriageway (paragraphs 30 and 31).

Proportionate evidence

National Highways did not withdraw its objection because the appellant had not followed its departures process, which would have required a risk assessment, a road safety audit and a walking, cycling and horse-riding report (paragraph 14). The inspector noted the small scale of the scheme and the minimal traffic it would add to the A120 (paragraph 15).

Referring to policy TR6 of the 2026 National Planning Policy Framework, which requires transport evidence proportionate to the nature and scale of the development, the inspector found the transport statement sufficient and the additional requirements excessive, even allowing for the busy road (paragraphs 17 and 18). The collision record, the low number of movements and the visibility showed the access to be safe, in accordance with Colchester Local Plan policy DM21 (paragraphs 19 to 21).

The costs decision

At the hearing it was explained that the departures procedure is an internal process for National Highways (costs decision, paragraph 6). The inspector found National Highways inflexible in its approach to the context of the site and the scale of the proposal: an approach suited to many accesses onto the strategic road network, but with insufficient regard to the circumstances of this case (paragraph 7).

The council, as planning authority, was required to take National Highways' representations into account but not bound to follow them. The inspector found that its officer report showed insufficient scrutiny of that advice, and that other material considerations had not been properly weighed (paragraphs 8 and 9). A full award was made against both, with the proportions to be agreed between them (paragraphs 2 and 13).

Points of interest and doubt

The decision does not suggest that the departures process has no place. The inspector accepted that National Highways' approach would suit many cases (costs decision, paragraph 7). The finding was that, for two pitches using an existing access with compliant visibility and very low traffic, the additional assessments were not necessary to reach a decision.

The decision also turns on agreed facts. Speeds and visibility were agreed in the statement of common ground, and the inspector's application of CD 109 followed from them. A case where the splays are disputed, or fall short of the relevant figure, would be likely to warrant fuller assessment. That is our reading rather than the inspector's stated reasoning.

For a larger scheme, or a new access onto the strategic road network, the requirements of National Highways and DfT Circular 01/2022 would carry more weight. The decision did not need to address that.

Practical points

• Agree speeds and visibility in a statement of common ground, so that the dispute narrows to what remains.
• Set out the standard and the table used, with the design speed, so the stopping sight distance can be checked.
• Confirm the highway boundary. Where the splay lies within it, a visibility condition may not be needed.
• Make the case for proportionate evidence early, by reference to the scale of the development and the traffic it would add.
• Plan for the vehicles that will use the access, including space for a vehicle and trailer to pull clear of the carriageway.