What Is a Classified Road?

Road classifications determine responsibility for the upkeep and maintenance of the roadway and contribute to traffic planning and GPS systems, which use categories to suggest the best routes for varied types of traffic.

Any classified road, such as an A, B or C road, is maintained by the relevant highway authority, and private users, such as businesses or homeowners, will need permission to make any modifications that affect the road, such as creating a new access route or fitting a dropped kerb.

UK Road Classifications Explained

Every public road carries a classification, depending on the traffic volumes the route is designed to support and how it integrates with the rest of the local roadway system.

The primary route network (PRN) defines how roads are shown on maps, with a hierarchy as follows:

• Motorways: major roads used by larger flows of traffic to connect cities and towns throughout the UK and maintained by Highways England.
• A roads: this category can be split into trunk roads and A roads, which provide larger capacity connections between regions or motorways.
• B roads: these roads also connect different regions and form routes between A roads and smaller, localised transport networks.
• C roads: the term ‘c road’ is informal and refers to any small road that connects unclassified roads, for example, a road that leads into a village, connects B roads in more rural areas, or is the primary entrance into a housing complex or residential location.

Unclassified roads are local roads or smaller access routes. These roadways are very common and comprise a large proportion of roads outside of major highways but are usually a low priority for maintenance resources.

Why Are Road Classifications Important?

As well as helping with traffic management, road classifications impact how highway authorities and local councils deal with roadway resurfacing and maintenance. 

Motorways are a good example where a serious pothole or surface deviation will be treated as a matter of urgency. In contrast, the same damage to a C road or unclassified route will be addressed less expediently.

Primary route networks designate the classification of routes between major cities and other key parts of the infrastructure, such as airports and ports, but the responsibility is divided between the central government and local authorities.

Where a primary route passes through several different areas within the scope of varied highway authorities, they must work collaboratively when dealing with upkeep requirements, signage, and any changes proposed to amend the classification of the road.

Maintenance and Performance Requirements for Classified Roads

There are technical implications linked to the classification of a road concerning:

• Monitoring and reporting of the road condition.
• Measuring surface performance, including skid resistance and structural stability.
• Routine maintenance, such as clearing debris, gritting roads in icy weather, or periodically renewing the roadway surface.

Highway managers must apply the appropriate requirements to ensure roads are inspected and maintained correctly, with various possible projects relating to drainage, safety fencing, adjacent footways and structural renewals for bridges, tunnels and underpasses.

Motorways and major A roads normally fall under the remit of Highways England, which takes charge of technological assets, such as cameras, emergency phones, and variable messaging displays.

National Highways traffic officers are also assigned to help keep elements of the Strategic Road Network (SRN) operating smoothly by responding to accidents, broken down vehicles, managing slow driving conditions and traffic jams, or keeping roadways clear of debris.

Design Considerations for Classified Road Networks

Alongside maintenance and monitoring, authorities must ensure that all parts of the classified road network are safe and comply with design and performance standards. 

For example, if a new junction is connected to a classified road as a primary access route, the responsible body needs to ensure the design adheres to the requirements around:

• Visibility and signage.
• Safe surfacing suited to the anticipated traffic volumes.
• Junction spacing and layout.
• Markings and priority for the right of way.
• Lighting and traffic signals.

Constructing a new roadway as a highway civil engineering project will depend on several variables. However, applying the correct road classification will ensure the surfacing and roadway sub-base are appropriate.

Traffic planners may also decide to construct roundabouts or additional traffic signals, where newly developed roads mean that the average daily traffic flow on an existing classified road may change.

The process normally involves a transport assessment, simulations to see how a junction, layout or signalling approach will work, and consultations with stakeholders and local communities before a new classified road or the management of a current route is modified.