Case Study:
Folly Hill Roundabout, Farnham, Surrey, UK
Patrick Parsons

Folly Hill Roundabout

Category: Highways, Roundabout
Company: Patrick Parsons
Status: Complete
Client: CALA Homes

Engineers at Patrick Parsons were appointed by CALA Homes to design and obtain s278 agreements to turn an existing T-junction into a roundabout, which would be the access into CALA’s proposed new residential development, Folly Hill. This would be the first job the team had done in Site3D, having recently made the transition from another software.

As well as marking the entrance to Folly Hill, having a roundabout in place of the existing T-junction would give multiple benefits to both vehicles and pedestrians: encouraging safer speeds for traffic passing through on the A-road, providing better turning from the existing junctioned road, and improving accessibility for pedestrians crossing over.

Engineers were also required to create a design that improved driver visibility. At the original T-junction, vehicles would drive over a hump in the junctioned road as they approached the turning. The team at Patrick Parsons was able to create straight line visibility all the way through the junction by smoothing the vertical levels. This also meant a better gradient for the vehicles waiting to pull away, where previously they’d be waiting on a steep slope.

Roundabout layout
Roundabout in construction

Image courtesy Google Street View

With the live updates to your road alignments in Site3D it’s much better than other software – it’ll make your life much easier.
– James Higgins, Principal Engineer at Patrick Parsons

They also widened the entrance of an existing private road that came out into the A-road slightly past the T-junction, providing a clearer view of any vehicles pulling out of the private road, as well as improving visibility out of their access as well.

The design needed to take pedestrian access into account – on the existing roads, there was no form of pedestrian crossing. The team added traffic islands to all roads coming off the roundabout so that residents in the development and the nearby estate could safely come and go.

Site3D certainly helped because our previous software didn’t design – you couldn’t put in a roundabout of ‘x’ dimensions as a base starter and then adjust it ... And in terms of time to get the initial drawings out to the council, that would’ve taken us a lot longer if we were doing it the previous way compared to how quickly we did it with Site3D.
– James Higgins, Principal Engineer at Patrick Parsons.

The design and the s278 works was quickly approved so that CALA Homes had the access they needed to get their residential development started. The site at Folly Hill now boasts an aesthetically pleasing roundabout that has brought down vehicle speed in the area, improved visibility, and improved both vehicle and pedestrian accessibility to the new development and existing estate.

Site3D screenshot