When Do You Need Highway Design?

Wednesday 29 May 2024

What is Highway Design?

The main purpose of Highway Design is to provide good connectivity and the safe movement of vehicles, cyclists and pedestrians between towns, cities and regions. Highway design blends engineering with environmental consciousness, aimed at forging transportation networks that connect communities whilst safeguarding the environment. Highway Design includes traffic management, sustainability initiatives, community engagement and a commitment to safety.

From strategic placement of signage and traffic signals to the incorporation of green infrastructure like sustainable drainage systems (SuDS), every aspect is carefully considered to create roads that not only facilitate efficient travel but also minimise environmental impact and enhance quality of life for all. By listening to concerns and incorporating feedback, designers ensure that roads are not just pathways for travel but lifelines for communities, connecting people to opportunities and services.

When Do You Need Highway Design?

Typically, Highway Design is required where planning permission has been granted for a new development, which requires new roads or improvements to the existing highway network.

Depending on the planning permission granted, the type of highway design required can vary significantly from simple T-Junction design through to large trunk roads with multiple lanes, signalised junctions or roundabouts.

The planning permission will have conditions and it is common for any highway design requirement of the approved scheme, such as the site access or off-site improvements, to be conditioned. It is then the role of the highway engineer to design and develop the consented scheme, such that it is suitable to enter into a highways agreement (S278 or S38) with the highway authority.

Considerations for Highway Design

To ensure highway design which is fit for purpose the engineer will need to consider and include, but not be limited to, the following factors:

  • Traffic and pedestrian flows.
  • Design standards to be applied.
  • Adopting authorities’ specific requirements.
  • Horizontal / vertical alignments and geometry.
  • Drainage of any surface water runoff.
  • Road markings, signage, street lighting and signals.
  • Environmental impacts.
  • Prevailing ground conditions.
  • How the design can be constructed and used safely.


If you would like to find out more or have a project that requires Highway Design, please get in touch. Here at PFA Consulting, we have a wealth of experience regarding Highway Design and have worked on many successful and diverse projects.