Why Access and Highways Matter When Assessing Land
Development must be capable of being accessed safely and must not create unacceptable impacts on highway safety or the surrounding transport network.
Access is one of the first technical matters considered when land is assessed for development. Councils need to understand how residents, employees, visitors, delivery vehicles, emergency services and refuse vehicles would reach the site and whether the proposed arrangement would operate safely.
The existence of a road frontage does not automatically mean that suitable access can be achieved. The road may be too narrow, vehicle speeds may be high or visibility may be restricted by bends, slopes, walls, hedgerows, trees, buildings or land outside the ownership of the person promoting the site.
Equally, an existing entrance that appears unsuitable does not necessarily prevent development. Highway engineers may be able to identify a different access position, enlarge the existing entrance, improve visibility, alter the road alignment or introduce measures that reduce vehicle speeds and improve safety.
The likely amount and type of traffic must also be considered. Ten homes will normally generate a very different pattern of movement from 300 homes, a school, a business park, a warehouse or a roadside service area. Larger developments are therefore likely to require more detailed evidence about traffic generation, junction capacity and the wider highway network.
Access is relevant both to planning applications and the promotion of land through Local Plans. A council considering whether to allocate a site will usually ask whether there is a reasonable prospect that safe access can be delivered and whether any necessary highway improvements are achievable and capable of being funded.
A site does not always need to have a fully designed access before it can be promoted. However, sufficient evidence should normally be available to demonstrate that there is a credible access solution. Where access relies on third-party land, major infrastructure or an uncertain highway intervention, the council may question whether the site is genuinely deliverable.
The key question is not simply whether land adjoins a road. It is whether a safe, suitable and deliverable access can be created for the proposed use and whether the resulting movement can be accommodated by the surrounding transport network.
Development Suitability
How Access Can Determine Whether Land is Developable
Highway access can influence whether development is acceptable in principle, how much land can be developed and what form the eventual proposal should take.
Highway Safety
Access should provide appropriate visibility and allow vehicles to enter, leave, slow down and turn without creating an unacceptable risk to road users, pedestrians or cyclists.
Traffic Generation
The type and amount of traffic generated by development will influence the design of the access, the evidence required and whether improvements are needed elsewhere on the road network.
Development Capacity
The capacity of an access or junction may affect the number of homes, amount of commercial floorspace or scale of employment development that can be accommodated.
Walking and Cycling
New development should normally provide safe and convenient routes for pedestrians and cyclists, particularly where the site is expected to connect with existing settlements, services or employment.
Emergency and Service Access
Fire appliances, ambulances, refuse vehicles, delivery vehicles and maintenance vehicles must be capable of reaching and moving safely through the development.
Cost and Deliverability
Major junction works, land acquisition, road widening, bridges or strategic transport improvements can materially affect the cost, viability and timing of development.
Highway considerations can also affect the layout of a site. The position of the entrance
will influence the internal road alignment, developable areas, drainage strategy, open space
and relationship with existing properties. A poorly located access may unnecessarily reduce
development capacity, while an appropriately designed entrance may create a logical and
efficient layout.
Early investigation is therefore important. It can prevent time and money being spent on a
planning strategy that depends on an unrealistic access arrangement. It can also identify
practical improvements that transform a site which initially appears constrained into a
credible development opportunity.
Safe and Suitable Access
What Makes an Access Suitable for Development?
A suitable access must respond to the characteristics of the road, the scale and type of development and the needs of every person or vehicle expected to use the site.
Adequate Visibility
Drivers leaving the site should be able to see approaching vehicles, cyclists and pedestrians from an appropriate distance having regard to actual traffic speeds and road conditions.
Appropriate Access Width
The entrance should be wide enough for the expected vehicles and may need to allow two vehicles to pass without waiting or reversing into the public highway.
Suitable Junction Geometry
Corner radii, gradients, alignment and entrance depth should allow vehicles to enter and leave smoothly without overrunning footways or obstructing the road.
Pedestrian Connections
Housing and other people-intensive uses may require footways, crossing points, dropped kerbs and connections to nearby services, facilities and public transport.
Vehicle Manoeuvring
The design should accommodate the largest vehicles reasonably expected to use the site, including refuse, delivery, emergency and service vehicles.
Network Capacity
The surrounding junctions and roads should be capable of accommodating the additional movement or capable of being improved through a proportionate and deliverable mitigation strategy.
Existing Field Accesses and Agricultural Gateways
Many potential development sites have an existing agricultural access. This may be a useful starting point but the existing lawful use of the entrance does not automatically establish that it can safely serve residential or commercial development.
Agricultural accesses may be used relatively infrequently, while a housing estate could generate vehicle movements throughout the day. The access may therefore need to be widened, repositioned or rebuilt with improved visibility, drainage, surfacing and pedestrian infrastructure.
In some cases the existing access is in the best location and can be upgraded. In others, a new entrance may provide a safer and more efficient solution.
Design Should Reflect the Proposed Use
An access suitable for a small group of homes may not be appropriate for a major housing allocation or employment development. The design must respond to the anticipated number, type and frequency of movements.
Access Visibility
What Are Visibility Splays?
Visibility splays are the areas that must generally remain clear so that a driver leaving an access can see approaching road users and has sufficient time to enter the highway safely.
Visibility is usually assessed in both directions from the proposed access. The required distance will depend on the type of road, recorded vehicle speeds, highway geometry and the design guidance applied by the relevant Highway Authority.
A visibility splay is commonly expressed using an X-distance and a Y-distance. The X-distance measures the driver's position back from the edge of the carriageway. The Y-distance measures how far the driver must be able to see along the road in each direction.
The Y-distance is particularly important because it relates to the distance an approaching vehicle may require to stop. Higher traffic speeds usually require longer visibility splays, while lower speeds may allow shorter distances where supported by appropriate guidance and evidence.
Visibility should normally be available within land controlled by the applicant or land forming part of the public highway. Where a visibility splay extends across third-party land, there may be uncertainty about whether vegetation, structures or other obstructions can be removed and kept clear permanently.
A plan showing an unobstructed line on a map is not always enough. The assessment may need to consider changes in road level, bends, crests, parked vehicles, boundary features and whether a driver's view is realistically available from the correct observation height.
The Main Elements of a Visibility Splay
X-Distance
The distance the driver's eye is positioned back from the edge of the carriageway before visibility is measured along the road.
Y-Distance
The distance the driver should be able to see along the highway in each direction from the access.
Recorded Vehicle Speed
Actual traffic speed can be more informative than the signed speed limit and may be established through an appropriate speed survey.
Obstructions
Walls, hedges, trees, signs, landform, structures and third-party boundaries may prevent the required visibility from being achieved.
Vegetation Removal
Hedges and vegetation may sometimes be cut back or repositioned, subject to ownership, ecology, landscape and legal considerations.
Access Relocation
Moving the entrance along the site frontage may avoid a bend, crest, obstruction or area of restricted visibility.
Highway Improvements
Local widening, altered road markings, junction works or other measures may improve the safety and operation of an access.
Speed Reduction
In appropriate circumstances, changes to the highway environment may reduce traffic speeds and support a revised access design.
Visibility should be investigated before relying on an access position. A measured plan, topographical survey and speed survey may be required where the highway geometry, levels or actual traffic speeds are uncertain.
Why Traffic Speeds Matter
The signed speed limit does not always reflect the speed at which vehicles actually travel, so recorded speed evidence can be important when the required visibility is assessed.
Posted Speed Limit
The speed limit provides an initial indication of the road environment but does not establish the speed of every approaching vehicle.
A road signed at 60 mph may have much lower actual speeds because of bends, width, topography or surrounding development. Conversely, vehicles may sometimes travel faster than the posted limit.
Relying solely on the speed limit may therefore result in visibility requirements that are either unnecessarily onerous or insufficiently robust.
Recorded Traffic Speed
A speed survey records the speed of vehicles passing the proposed access location over a defined period.
The results can help establish the appropriate stopping sight distance and may be used to support the visibility splays proposed by the highway engineer.
Survey timing, equipment position, weather, roadworks and abnormal traffic conditions should be considered so that the results provide a reliable picture of normal highway conditions.
Technical Highway Evidence
What Highway Assessments May Be Needed?
The level of technical evidence should be proportionate to the scale, location and transport effects of the proposed development.
A preliminary review may be sufficient to identify whether land appears to have a realistic access opportunity. As the planning or Local Plan promotion process progresses, more detailed reports may be required to demonstrate that the access can be designed safely and that the surrounding transport network can accommodate the proposal.
The correct assessment should be agreed with an experienced transport or highway consultant. Producing a full Transport Assessment at the earliest stage may be unnecessary, while relying on a short desktop note for a major strategic development may provide insufficient evidence.
Preliminary Highway Review
A desktop review can identify the road classification, speed limit, existing access points, nearby junctions, pedestrian infrastructure and obvious constraints requiring further investigation.
Access Appraisal
An access appraisal considers whether a safe entrance appears achievable, where it should be located and what visibility, width, geometry or highway improvements may be required.
Topographical Survey
A topographical survey records levels, boundaries, road features, vegetation and other physical information needed to design the access accurately and test visibility.
Transport Statement
A Transport Statement provides a proportionate assessment of the site's accessibility, expected travel demand, access arrangements and transport effects for proposals with more limited impacts.
Transport Assessment
A Transport Assessment is a more detailed report normally used for developments that may generate significant movement or materially affect junctions and the wider road network.
Travel Plan
A Travel Plan sets out measures intended to reduce dependence on private cars and support walking, cycling, public transport, car sharing and other sustainable travel choices.
Swept Path Analysis
Swept path drawings test whether cars, refuse vehicles, emergency appliances, buses or articulated lorries can manoeuvre through the access and internal road layout.
Road Safety Audit
An independent Road Safety Audit may be required to identify potential safety issues arising from a new or altered access, junction or highway improvement scheme.
Traffic and Speed Surveys
Survey data may be needed to establish traffic volumes, vehicle classifications, turning movements, queues and recorded speeds before access or junction effects can be assessed.
Early Local Plan Promotion
At an early Local Plan stage, the purpose of the highway evidence is normally to show that there is a credible access solution and that no obvious highway constraint makes the site unsuitable or undeliverable.
An access appraisal, concept plan and preliminary review of the surrounding network may therefore be sufficient, depending on the scale and circumstances of the site.
Planning Application
A planning application generally requires more detailed evidence because the access design, development quantum and transport effects must be assessed before permission can be granted.
The required package may include surveys, detailed plans, vehicle tracking, junction modelling, a Transport Statement or Transport Assessment and consultation with the Highway Authority.
Highway evidence should develop alongside the planning strategy. The initial objective is to identify whether a realistic solution exists. Detailed surveys, modelling and design can then be commissioned when they are proportionate and capable of advancing the site.
Understanding Existing Highway Conditions
Why Traffic Counts and Highway Surveys Are Needed
Traffic surveys provide the evidence needed to understand how the existing road network operates before the additional movement generated by development is assessed.
A highway assessment should normally be based on reliable evidence rather than assumptions about whether a road appears busy or quiet. Traffic volumes can vary significantly according to the time of day, day of the week, season, school term, nearby land uses and the wider function of the road.
Traffic counts help establish the number and type of vehicles using a road or junction. The information may then be used to assess existing capacity, identify peak periods, calculate future traffic conditions and test whether development would create unacceptable highway effects.
Different survey methods are used for different purposes. A speed survey may help establish visibility requirements, while a turning count may be needed to understand how vehicles move through a junction. Queue surveys and journey-time observations may also be required where congestion is already a concern.
The survey scope should be proportionate to the proposal. A small residential development may require relatively limited evidence, while a strategic housing site, logistics park, industrial estate or major commercial development may require data from several junctions across a wider study area.
Automatic Traffic Counts
Automatic traffic counters are normally placed across the carriageway to record traffic volumes and speeds over several days. They can help identify daily patterns, peak periods and differences between weekday and weekend traffic.
Turning Movement Counts
Turning counts record how vehicles move through a junction, including left turns, right turns and straight-ahead movements. The results are commonly used within junction capacity modelling.
Classified Vehicle Counts
Classified counts distinguish between cars, vans, buses, motorcycles and different types of heavy goods vehicle. This can be particularly important for employment, industrial and logistics proposals.
Speed Surveys
Speed surveys measure how quickly vehicles travel past the proposed access and can help establish the visibility splays and stopping sight distance likely to be required.
Queue Length Surveys
Queue surveys record the length and duration of vehicle queues at junctions. They can help demonstrate whether congestion is temporary, recurring or likely to be materially affected by development.
Pedestrian and Cycle Surveys
Surveys may also record pedestrian and cycle movement where the proposal could affect an existing route or where new crossing facilities and sustainable transport connections are being considered.
When Should Traffic Surveys Be Undertaken?
Surveys should normally be carried out during representative traffic conditions. School holidays, public holidays, major roadworks, severe weather or unusual events may produce results that do not accurately reflect normal network operation.
Where a site is close to a school, tourist destination, seasonal business or major employer, the survey programme may need to reflect the particular periods when movement is greatest.
Existing Traffic Is Only the Starting Point
Highway assessments may also need to account for committed developments, planned infrastructure, background traffic growth and other allocated sites likely to affect the network.
The assessment should therefore consider the appropriate future year rather than relying solely on traffic conditions recorded on the survey date.
Transport Evidence
Transport Statements and Transport Assessments
Transport Statements and Transport Assessments explain how development will be accessed, how much movement it may generate and whether its effects can be accommodated or mitigated.
Transport Statement
A Transport Statement is normally prepared where a development is expected to have relatively limited transport effects but still requires a structured assessment of access, movement and sustainable transport.
The report may describe the site, existing road conditions, local services, walking and cycling routes, public transport, parking, expected traffic generation and the design of the proposed access.
Depending on the circumstances, it may also include limited survey data, vehicle tracking and a review of personal injury collision records.
Transport Assessment
A Transport Assessment is generally required where development is likely to generate more substantial movement or affect several junctions and routes.
It will normally contain detailed survey evidence, trip generation and distribution assumptions, junction capacity assessments, future traffic scenarios, sustainable transport measures and proposed mitigation.
The scope should usually be discussed with the relevant Highway Authority before the assessment is finalised.
There is no universal development size at which every council will require the same report. The appropriate evidence depends on the proposed use, traffic generation, accessibility of the location, sensitivity of the road network and requirements of the Highway Authority.
Highway Network Operation
How Junction Capacity Is Assessed
Junction capacity assessments test how existing and proposed junctions are likely to operate after development traffic is added to the network.
Development frequently increases movement through nearby junctions. The relevant question is not simply whether the proposal adds traffic, because almost every form of development will do so. The assessment considers whether the junction can continue to operate acceptably or whether proportionate mitigation is required.
Traffic survey data is entered into recognised modelling software together with the expected traffic generated by the development. The model may assess queue lengths, delays, capacity, flow patterns and the relationship between demand and the practical capacity of the junction.
Different tools may be used depending on whether the junction is a priority junction, roundabout, signal-controlled junction or more complex network. The Highway Authority may specify the modelling approach and assumptions it expects the applicant to use.
Modelling should test appropriate future scenarios. These may include existing traffic, committed development, general background growth, the proposed development and any highway improvement package.
A junction that experiences some congestion is not automatically unsuitable. Many urban junctions operate under pressure during peak periods. The planning assessment considers the degree of change, the reliability of the evidence, highway safety and whether the overall effects would be unacceptable.
Capacity Assessments May Consider
- Existing traffic volumes and turning movements
- Traffic generated by committed developments
- Future background traffic growth
- Expected development traffic
- Queue lengths and vehicle delay
- Junction capacity and operational performance
- The effect of proposed highway improvements
Priority Junctions
Modelling can test side-road movements, main-road flows, queueing and whether additional capacity or a revised layout is required.
Roundabouts
Assessments consider how vehicles enter, circulate and leave the roundabout and whether development changes queues or delay on individual approaches.
Signal Junctions
Signal modelling can examine stage timings, pedestrian phases, saturation, queues and whether alterations to the signal arrangement could improve capacity.
Highway Networks
Larger schemes may require several connected junctions to be assessed together so that wider traffic distribution and interaction can be understood.
Residential Development
What Access Is Needed for Housing Development?
Housing sites need adequate access for residents, visitors, pedestrians, cyclists, emergency services, refuse collection and delivery vehicles.
The access requirements for housing depend on the number of homes, the type of road serving the site and the way the internal layout is intended to operate. A small infill development may be served by a private drive, while a larger residential scheme will normally require an estate road designed to an appropriate adoptable or private standard.
The Highway Authority will consider whether the entrance has sufficient width, visibility and capacity. It may also review gradients, drainage, road geometry, pedestrian routes, crossing facilities, parking, turning arrangements and whether vehicles can enter and leave the site in forward gear.
Refuse and emergency access can be particularly important. A layout that cannot accommodate a fire appliance or refuse vehicle may require substantial revision even where the principal access from the public highway is otherwise acceptable.
Larger housing developments may need more than one access. A secondary connection can improve emergency resilience, distribute traffic and create better links with surrounding neighbourhoods. Whether a second point is necessary will depend on the scale and design of the proposal and the standards applied by the Highway Authority.
Development Quantum
The number of homes affects traffic generation, access width, internal road design and whether a single entrance is likely to be sufficient.
Footway Connections
Safe pedestrian links may be needed between the site and nearby homes, schools, shops, bus stops, employment and community facilities.
Emergency Access
Emergency vehicles must be able to reach the homes. Larger schemes may need a second connection, emergency route or suitable turning arrangement.
Refuse Collection
Refuse vehicles should be able to enter, circulate and leave without excessive reversing or creating unsafe conflicts with pedestrians and parked cars.
Parking and Turning
Adequate parking, visitor spaces and turning areas can reduce obstruction, unsafe reversing and overspill parking on surrounding roads.
Internal Road Layout
Road hierarchy, shared surfaces, private drives, cycle routes and pedestrian connections should create a safe, legible and well-connected residential environment.
An agricultural gateway can sometimes be upgraded to serve housing, but the existing entrance must be assessed against the much greater frequency and variety of movements created by residential development.
Employment and Commercial Development
How Strong Transport Networks Can Create Promising Employment Land
Land with good access to major roads, motorway junctions, freight routes and established employment centres can become highly attractive for industrial, logistics and commercial development.
Employment land is often assessed differently from residential land because businesses may place particular importance on strategic connectivity. Warehousing, logistics, manufacturing and distribution uses frequently need efficient access to motorway junctions, trunk roads, ports, airports, rail freight facilities and major population centres.
A site located close to a strong highway network may therefore have employment potential even where it is less closely related to an existing residential settlement. The commercial attractiveness of the land may be driven by journey times, freight access, labour availability and the ability to serve regional or national markets.
Councils preparing Local Plans examine future employment needs and the type of land required by different sectors. A well-connected site may be considered for allocation where existing employment areas cannot provide suitable plots, modern buildings, large floorplates or direct access to the strategic road network.
Strategic highway access can therefore create development opportunities that would not exist for more isolated land. This is particularly relevant near motorway corridors, established industrial clusters, distribution hubs and locations where new road infrastructure is planned.
However, employment uses may generate significant numbers of heavy goods vehicles, delivery vehicles and staff movements. The access and surrounding highway network must therefore be capable of accommodating the size, weight and turning requirements of those vehicles.
Features That Can Strengthen Employment Potential
- Proximity to a motorway or major trunk road junction
- Direct access to an established freight corridor
- Nearby industrial, logistics or commercial development
- Sufficient frontage for a commercial access
- Space for large vehicles to turn and manoeuvre
- Good access to an available workforce
- Planned highway or transport infrastructure
Logistics
Logistics sites often depend on fast and reliable access to the strategic road network and sufficient space for articulated vehicles.
Manufacturing
Manufacturing land may need access for employees, raw materials, servicing and the distribution of finished goods.
Warehousing
Warehousing often requires wide access points, generous turning areas, loading yards and routes capable of accommodating heavy vehicles.
Business Parks
Office and business parks require access for staff and visitors together with strong walking, cycling and public transport connections where practical.
Highway Consultation
Why the Highway Authority Should Be Engaged
Early engagement with the relevant Highway Authority can help establish what evidence, design standards and mitigation measures are likely to be required.
The Local Highway Authority is usually responsible for most local roads. Depending on the area, this may be a county council, unitary authority, metropolitan authority or London borough. National Highways is responsible for the strategic road network, including motorways and certain major A-roads.
The planning authority and Highway Authority may be separate organisations. A district council may determine the planning application while the county council provides technical highway advice as a statutory consultee.
Highway officers may comment on access visibility, road width, junction capacity, pedestrian connections, public transport, parking, servicing, road safety and the need for off-site works. Their response can have a major influence on whether planning permission is granted or whether land is considered suitable for allocation.
Early consultation can help avoid designing an access around assumptions that the Highway Authority does not accept. It can also clarify the survey area, modelling assumptions, assessment year, committed developments and type of technical report required.
Engagement is particularly valuable for large or technically complex sites. A transport scoping note can set out the proposed methodology before extensive surveys and modelling are commissioned, reducing the risk that the work later has to be repeated.
Local Highway Authority
Responsible for most local roads and commonly consulted on planning applications, Local Plan allocations and highway improvement proposals.
National Highways
May need to be engaged where development could materially affect a motorway, strategic A-road or junction forming part of the strategic road network.
A highway officer's initial concern does not always mean that development is impossible. Concerns may be addressed through further evidence, a revised access design, reduced development quantum or a proportionate package of highway improvements.
Addressing Highway Constraints
Can Difficult Access and Highway Issues Be Solved?
Many highway constraints can be addressed through access redesign, additional land, engineering works, sustainable transport measures or changes to the scale and layout of the development.
Land should not necessarily be dismissed because the existing entrance is narrow, visibility is restricted or a nearby junction operates under pressure. The correct question is whether a safe and proportionate solution can realistically be delivered.
The most appropriate intervention will depend on the nature of the problem. Minor sites may only require an improved bellmouth, visibility clearance or pedestrian connection. Larger schemes may need road widening, turning lanes, signal improvements, roundabouts, crossings or wider network mitigation.
The land required for an improvement must be controlled or capable of being acquired. Engineering solutions that depend on third-party land, statutory undertaker works or substantial public infrastructure should be investigated carefully because they can affect cost, timing and deliverability.
Access Widening
An entrance may be widened to allow vehicles to pass, improve turning movements and prevent waiting or reversing on the highway.
Relocated Access
A new entrance may provide better visibility, safer geometry or a more efficient internal layout than the existing gateway.
Right-Turn Lane
A dedicated turning lane may reduce obstruction and rear-end collision risk where a significant number of vehicles will turn into the site.
New Roundabout
Larger developments may be served by a new or improved roundabout capable of distributing traffic between several routes.
Signal Improvements
Traffic signals may be introduced or adjusted to manage turning movements, pedestrian crossings and capacity at constrained junctions.
New Footways and Crossings
Footways, refuge islands, controlled crossings and cycle links can improve accessibility and reduce reliance on private cars.
Speed Management
Gateway features, road markings, altered geometry and other measures may help create a lower-speed environment where appropriate.
Public Transport Measures
New bus stops, service contributions, travel information and improved walking routes may form part of the transport mitigation strategy.
Phased Infrastructure
Larger highway works may be linked to development phases so that improvements are delivered before agreed occupation or traffic thresholds are reached.
Highway Improvements Must Be Deliverable
A technically possible solution may still be unsuitable if the necessary land cannot be acquired, statutory approvals are uncertain or the cost would make the development unviable.
The highway strategy should therefore be assessed alongside land ownership, utility diversions, drainage, ecology, landscape, planning obligations and development viability.
Early Advice Can Unlock Land
An early access appraisal can identify solutions before the planning strategy and illustrative layout become fixed around an unsuitable entrance.
Site-Specific Constraints
Common Access and Highway Constraints
Highway constraints often overlap with land ownership, landscape, drainage, ecology, utilities and the physical characteristics of the road.
Narrow Roads
Limited carriageway width may make vehicle passing difficult and may constrain the type or scale of development unless widening or passing places can be provided.
Restricted Visibility
Bends, crests, buildings, walls, hedgerows, trees and changes in level may restrict the distance drivers can see from the access.
Trees and Hedgerows
Vegetation may need to be removed or managed, but ecological value, protected trees, nesting birds and landscape character must also be considered.
Third-Party Land
Access widening, visibility splays or junction works may extend beyond the landowner's title and depend on acquiring rights or land from another party.
Ditches and Drainage
Roadside ditches, culverts and surface water routes may affect the position, level and engineering design of the access.
Utilities
Telecoms equipment, electricity cables, gas pipes, water mains and highway drainage may need to be protected or diverted.
Steep Gradients
Sloping land can affect visibility, vehicle control, drainage, accessibility and the ability to create a suitable junction and internal road.
Historic Features
Listed walls, bridges, milestones, conservation areas and other heritage features may restrict widening or alteration of the highway frontage.
Bridges and Structures
Weight restrictions, bridge capacity, railway crossings and retaining structures may constrain routes used by development traffic.
The presence of a constraint does not determine the outcome by itself. The important issue is whether it can be avoided, mitigated or resolved through a proportionate and deliverable design.