Can You Build a New Access onto the Strategic Road Network? A Developer's Guide
Development sites alongside major roads can present significant opportunities, particularly for commercial, employment, logistics and roadside uses. However, where a site fronts the Strategic Road Network (SRN), the ability to create a new access, or make greater use of an existing access, can become one of the key considerations in determining whether a development is deliverable.
There is sometimes an assumption that National Highways will not permit a new access onto the SRN under any circumstances. The actual position is more nuanced.
National policy places clear restrictions on new connections to the SRN, particularly on high-speed routes, and developers should not assume that direct access will be acceptable simply because a site has road frontage. Nevertheless, the policy position varies according to the nature of the route, the type of connection proposed and the circumstances of the development.
Understanding this distinction at an early stage can be critical when assessing the development potential of a site.
What is the Strategic Road Network?
The Strategic Road Network in England comprises the motorways and major A-roads managed by National Highways.
Its primary purpose is to provide safe and efficient movement between the country's main centres of population and economic activity. It performs a different function from the local highway network and, consequently, development affecting the SRN is subject to specific policy and technical requirements.
National Highways is consulted on planning applications where development has the potential to affect the operation or safety of the SRN.
This can include development immediately adjoining a strategic route, but it can also include development some distance away where traffic generated by the proposal would materially affect an SRN junction.
Can a New Access Be Created onto the SRN?
Potentially, but the starting point is restrictive.
The principal policy document is Department for Transport Circular 01/2022, Strategic Road Network and the Delivery of Sustainable Development. The Circular sets out the approach National Highways takes when engaging with the planning system.
For high-speed routes, there is a presumption against the creation of new connections. This reflects the fundamental purpose of these roads: providing safe and efficient strategic movement rather than direct access to individual developments.
The policy position on other parts of the SRN is more graduated. Even in these locations, however, National Highways will normally expect opportunities to make use of existing junctions and connections to be considered before a new connection to the network is proposed.
This means that a new access should not necessarily be regarded as impossible, but neither should it be treated in the same way as an access onto an ordinary local road.
The particular circumstances of the site and development matter.
High-Speed Routes Require Particular Caution
A distinction needs to be made between different parts of the SRN.
A proposal for a new direct access onto a motorway or high-speed dual carriageway presents very different policy and highway-safety considerations from an access proposal affecting a lower-speed all-purpose trunk road.
For high-speed routes, Circular 01/2022 establishes a strong presumption against new connections. Exceptions are limited and developers should therefore be extremely cautious about progressing a development strategy dependent upon the creation of such a connection.
Where access is fundamental to the development of a site, the issue should be investigated before significant expenditure is committed to masterplanning, land acquisition or preparation of a planning application.
What About Lower-Speed A-Roads?
The fact that an A-road forms part of the SRN does not automatically mean that every section of it has motorway-like characteristics.
Some strategic A-roads pass through or alongside settlements, contain existing frontage development and incorporate conventional at-grade junctions and accesses.
The policy and technical assessment of a proposed connection in these circumstances can therefore be quite different from that applying to a high-speed grade-separated route.
National Highways will still consider the strategic function of the road, but matters such as the existing character of the route, speed environment, junction form, traffic flows, collision history and availability of alternative access arrangements can all become relevant.
It is therefore important to understand the characteristics of the particular section of SRN rather than simply concluding that an access is unacceptable because the road is managed by National Highways.
Existing Accesses Can Be Particularly Important
Many development sites adjoining the SRN already benefit from some form of vehicular access.
This can materially change the nature of the assessment.
There is an important distinction between creating an entirely new connection and proposing the continued, altered or intensified use of an established access.
For example, a former commercial site, petrol filling station, industrial premises or roadside business may already have a lawful connection to the SRN. Redevelopment could change the volume, type or pattern of traffic using that connection.
The relevant questions may therefore include:
What is the existing lawful use of the site?
What level and type of traffic could the existing use generate?
How has the access historically operated?
Would the proposed development increase or reduce turning movements?
Does the existing access meet appropriate geometric and visibility requirements?
Can the access be improved as part of the development?
Would rationalising several existing accesses into a single improved connection provide a highway benefit?
An existing access should not simply be assumed to provide an unrestricted right to accommodate any future development. Equally, its presence can be a highly relevant consideration when developing an appropriate access strategy.
Could an Existing Access Be Relocated?
In some circumstances, relocating an existing connection may provide a better overall highway solution.
For example, an existing access may have poor visibility, an undesirable relationship with another junction or inadequate geometry. A development proposal might provide an opportunity to close that access and replace it with one in a safer location.
This needs careful consideration because National Highways will need to assess the proposal against its policy for connections to the SRN.
Nevertheless, the highway consequences of the proposal should be considered as a whole. A scheme which removes a substandard arrangement and replaces it with a materially better solution may present a different case from a proposal simply seeking an additional connection for development convenience.
What Will National Highways Consider?
There is no single test that determines whether an access proposal will be acceptable.
Depending upon the circumstances, the assessment is likely to consider matters including:
the classification and function of the road;
existing traffic flows;
vehicle speeds;
collision records;
visibility;
access and junction geometry;
proximity to other accesses and junctions;
predicted development traffic;
turning movements;
the type and size of vehicles using the access;
opportunities to use an existing connection;
alternative means of accessing the site;
effects upon the safety and operation of the SRN; and
opportunities for access by sustainable transport modes.
Where a new or altered junction is proposed, the design will also need to respond to the relevant requirements of the Design Manual for Roads and Bridges (DMRB).
The level of assessment should be proportionate to the scale and nature of the proposal, but significant access works can require detailed geometric design, traffic analysis and Road Safety Audit.
DMRB Compliance
Development proposals affecting the SRN will commonly need to be considered against the Design Manual for Roads and Bridges.
For at-grade priority and signal-controlled junctions, the relevant requirements are contained within DMRB CD 123, together with other applicable DMRB documents depending upon the nature of the scheme.
This is an important distinction from many development accesses onto local roads, where local highway authority standards or guidance such as Manual for Streets may have a greater role.
A concept which appears perfectly reasonable on a planning layout may therefore require considerably more detailed investigation when it interfaces with the SRN.
Visibility, junction spacing, geometry, design speed and the interaction between different road users should be considered at an early stage.
Road Safety Audit
Where works affecting the SRN are proposed, Road Safety Audit requirements should also be considered early in the design process.
This should not be treated simply as an exercise undertaken after the access design has effectively been fixed.
Early consideration of road safety can identify issues which influence the fundamental geometry of a proposed junction and can avoid significant redesign later in the planning process.
For more substantial proposals, engaging with National Highways before submission of a planning application can therefore be particularly valuable.
Practical Examples: How Different SRN Access Proposals Might Be Approached
The policy relating to new connections to the Strategic Road Network cannot sensibly be considered in isolation from the characteristics of the site and the road concerned. The following examples illustrate how apparently similar access issues can require very different approaches.
Scenario 1 – Redevelopment of a Petrol Filling Station with an Existing SRN Access
A petrol filling station or other established roadside use may already have one or more direct accesses onto the Strategic Road Network. A redevelopment proposal might introduce a convenience store extension, drive-through unit, additional commercial use or a wider redevelopment of the site.
In this situation, the starting point would not normally be to consider the proposal as though an entirely new connection to the SRN were being created. The existing access arrangements, their lawful use and the traffic associated with the existing site are all important considerations.
An initial transport review should establish how the existing accesses operate, their geometry and visibility, the nature and volume of existing vehicle movements and whether the proposed development would materially alter the pattern of traffic entering and leaving the site.
The development may also provide an opportunity to improve the existing highway arrangement. For example, there may be scope to rationalise multiple accesses, improve visibility, modify entry and exit geometry or provide clearer internal circulation.
Traffic generation also requires careful consideration. A new commercial use within an established roadside site does not necessarily result in every customer journey being a completely new trip on the surrounding highway network. Depending upon the use and location, some visits may comprise pass-by, diverted or linked trips associated with traffic already travelling along the route.
The important issue is therefore to understand the net effect of the development, rather than simply comparing the gross number of vehicle movements associated with the proposed use against zero.
Initial approach: establish the existing lawful and physical access position, understand existing and proposed traffic movements, identify whether the access arrangement can be improved and determine the actual change in effect upon the SRN.
Scenario 2 – New Commercial Development on a Lower-Speed Trunk Road
Consider a development site fronting an all-purpose trunk road which forms part of the SRN but passes through a lower-speed environment containing existing junctions, accesses and frontage development.
A new access in this situation still needs to be considered carefully against National Highways policy. However, the characteristics of the road are fundamentally relevant.
The first step would be to establish the function and existing character of the route. This would include reviewing the speed limit and actual vehicle speeds, traffic flows, collision history, nearby junctions and accesses, visibility and the nature of surrounding development.
Alternative means of accessing the site should also be investigated. If a satisfactory connection can reasonably be achieved from the local highway network, National Highways is likely to expect that option to be properly considered.
Where direct access from the SRN is being pursued, it would be necessary to establish whether an appropriate junction arrangement can physically be provided and whether it could operate safely without materially compromising the strategic function of the route.
This is where early feasibility work becomes particularly valuable. Visibility splays, junction geometry, levels, land ownership and the position of neighbouring accesses can be examined before the development layout becomes fixed.
The fact that a road forms part of the SRN should therefore trigger detailed investigation, rather than an automatic conclusion that the site cannot be accessed.
Initial approach: understand the particular section of SRN, investigate alternative access opportunities, establish the feasibility of a compliant junction and engage with National Highways at an early stage where the development relies upon direct SRN access.
Scenario 3 – Greenfield Development Adjacent to a High-Speed Dual Carriageway
A greenfield development site adjoining a high-speed dual carriageway presents a substantially different proposition.
Where the development strategy depends upon creating an entirely new direct connection to a high-speed section of the SRN, the policy position is considerably more restrictive.
In these circumstances, the first question should not be how the new junction can be designed. It should be whether the development strategy can realistically rely upon a new connection at all.
Existing junctions and alternative connections through the surrounding highway network should be investigated at the outset. The development team should also consider whether the site can be masterplanned to connect to an existing or planned local road rather than creating an additional point of access to the strategic route.
This is an important distinction. Significant expenditure can be incurred developing a detailed junction design which may face a fundamental policy objection irrespective of its geometric standard.
Where exceptional circumstances are considered to exist, these would need to be identified and discussed with National Highways at a very early stage. The technical assessment is also likely to be substantially more involved than for a conventional development access.
For a prospective purchaser or promoter, dependence upon an entirely new connection to a high-speed strategic route should therefore be regarded as a significant development risk until the access strategy has been properly investigated.
Initial approach: establish the policy position before undertaking detailed design, exhaust reasonable alternative access strategies and seek early engagement with National Highways before committing substantial resources to a development concept dependent upon a new SRN connection.
The Same Question Can Have Very Different Answers
These examples demonstrate why asking simply “Can I have a new access onto the Strategic Road Network?” does not provide enough information to determine whether a development is likely to be acceptable.
An established roadside business with an existing access, a commercial site alongside a lower-speed all-purpose trunk road and a greenfield development adjoining a high-speed dual carriageway all interact with the SRN, but the policy and technical considerations can be very different.
The appropriate starting point is therefore a site-specific review of the road, the existing access position, the development proposals and the realistic alternatives.
In many cases, this can be undertaken at an early stage and before a developer commits significant expenditure to detailed design or a planning application.
The Importance of Pre-Application Advice
Where a development depends upon a new, relocated or materially altered connection to the SRN, obtaining early technical advice can substantially reduce development risk.
The first stage should normally establish:
whether the road forms part of the SRN;
the characteristics and speed environment of the route;
the relevant policy position;
existing access rights and arrangements;
potential alternative access options;
whether an appropriate junction can physically be accommodated;
likely visibility and geometric requirements; and
the likely scope of supporting transport evidence.
This work can often identify a fundamental constraint before significant expenditure is incurred elsewhere in the planning process.
Where appropriate, an initial access feasibility assessment can then form the basis for pre-application discussions with National Highways.
Do Not Design the Development Before Testing the Access
One of the most common mistakes is to develop a detailed site layout first and consider highway access afterwards.
For sites adjoining the SRN, this approach can create significant problems.
The access may influence where development can be positioned, internal circulation, levels, drainage, visibility, landscaping and even the amount of developable land available.
The preferred approach is therefore to establish an access strategy alongside the emerging masterplan.
Where several options are available, these can be assessed comparatively before a preferred solution is developed.
Is a New SRN Access a Development 'Red Flag'?
It should certainly trigger early investigation, but it does not necessarily mean that a site is undevelopable.
The critical question is not simply:
"Is this road part of the Strategic Road Network?"
It is:
"What type of strategic road is this, what access arrangement is being proposed, what alternatives exist, and can the proposal be demonstrated to operate safely without compromising the function of the network?"
Those questions require consideration of both planning policy and highway engineering.
For developers considering the purchase or promotion of land adjoining the SRN, establishing the likely access position early can therefore be one of the most valuable pieces of initial due diligence.
Frequently Asked Questions
Can I build a new access onto an A-road?
Possibly, but the first question is whether the A-road forms part of the Strategic Road Network. Many A-roads are managed by local highway authorities rather than National Highways.
Where the road forms part of the SRN, the proposal will need to be considered against National Highways policy, including DfT Circular 01/2022, as well as the particular characteristics of the road and the proposed development.
Will National Highways allow a new access?
There is no single answer that applies to every section of the Strategic Road Network.
There is a strong presumption against new connections on high-speed sections of the SRN. Elsewhere, the position is more nuanced, although National Highways will normally expect reasonable opportunities to use existing connections and alternative access arrangements to be considered first.
Early feasibility work can therefore be particularly important where the viability of a development depends upon direct access to the SRN.
Can an existing access onto the Strategic Road Network be intensified?
Potentially. The existence of an established access can be an important consideration, but it does not automatically mean that the access can accommodate any scale or type of redevelopment.
The assessment should consider the existing lawful use of the site, existing and potential traffic movements, access geometry, visibility, vehicle types and the change in highway effect associated with the proposed development.
In some circumstances, redevelopment can also provide an opportunity to improve, relocate or rationalise an existing access arrangement.
What should I do if National Highways objects to my proposed access?
The first step is to understand precisely why the objection has been raised.
An objection may relate to the principle of creating a new connection, the availability of an alternative access, highway safety, junction geometry, traffic effects or insufficient supporting information.
The appropriate response will depend upon the reason for the objection. In some cases further technical evidence or amendments to the access design may address the concern. In others, the fundamental access strategy may need to be reconsidered.
Obtaining specialist transport advice before responding can help distinguish between a technical issue that may be capable of resolution and a more fundamental policy constraint.
How DW Transportation Can Help
DW Transportation provides transport planning and highway advice for development proposals throughout England and Wales.
We can undertake an initial review of sites adjoining the Strategic Road Network to identify potential access constraints, consider alternative access strategies and advise on the likely technical information required to support discussions with National Highways.
Where a scheme progresses, this can extend to access feasibility work, Transport Statements and Transport Assessments, junction analysis, access design coordination and support through pre-application and planning discussions.
If you are considering a development site adjoining a motorway or trunk road, obtaining transport advice before fixing the site layout can help identify potential constraints and opportunities at an early stage.