A pavement design engineer designs the structural make-up of roads, car parks and other trafficked surfaces - specifying the materials and layer thicknesses needed to carry the expected traffic loading without failure over the design life. In the UK, pavement design for adoptable roads must follow the relevant highway authority standard and is a core requirement for Section 38 adoption packages. The pavement design depends on the subgrade strength (measured as a CBR value), the design traffic loading in million standard axles (msa) and the design life - typically 20 years for residential roads.
What they do
- Carry out CBR testing and subgrade characterisation
- Calculate design traffic loading in million standard axles
- Select pavement construction type - flexible, rigid or composite
- Specify layer thicknesses and materials for sub-base, base and surface course
- Produce pavement design reports for highway authority approval
- Design permeable pavements for SuDS compliance
- Assess existing pavements for strengthening requirements
- Specify temporary haul roads and construction access surfaces
When you need one
A pavement design engineer is required whenever a road or trafficked surface must be designed to a specific standard - most commonly for Section 38 adoptable roads and heavily loaded car parks or industrial areas.
Typical costs (UK, 2025)
| Job type | Typical cost |
|---|---|
| Road pavement design report | £800 - £2,500 |
| Car park pavement design | £600 - £1,800 |
| Pavement investigation and assessment | £700 - £2,000 |
| Pavement strengthening design | £800 - £2,000 |
| Permeable pavement design | £600 - £1,500 |
| Hourly rate | £75 - £130 / hr |
Costs vary with the size of the scheme and whether CBR or deflectograph testing is required. Laboratory testing is usually charged separately. Confirm whether the fee includes highway authority liaison and comment responses.
Qualifications to look for
The primary professional body for pavement design engineers working on highway schemes. MCIHT members are recognised by highway authorities across the UK. Check membership at ciht.org.uk.
Many pavement engineers hold CEng status via the ICE, particularly those working on major infrastructure. Both MCIHT and MICE are accepted by highway authorities for Section 38 pavement design.
How to find a reputable pavement design engineer
Frequently asked questions
What is flexible pavement?
Flexible pavement is the most common road construction type in the UK - using layers of compacted aggregate (sub-base, base) with a bituminous (asphalt) surface. The layers flex under traffic loading, spreading stresses to the subgrade. The design specifies the thickness and material properties of each layer based on the traffic loading and subgrade strength.
What is rigid pavement?
Rigid pavement uses a concrete slab (reinforced or unreinforced) which distributes loads over a wide area due to its rigidity - used for heavily loaded areas such as lorry parks, aircraft aprons and some industrial floors. Rigid pavements have a longer design life than flexible pavements but higher initial cost and are less easy to repair.
How is pavement design determined?
The UK standard for residential roads is LR1132 and for trunk roads CD 226. Pavement thickness depends on design traffic loading (expressed in million standard axles), subgrade strength (CBR value from testing) and the required design life - typically 20 years for residential roads. The pavement design engineer selects appropriate materials and layer thicknesses to meet these parameters.