Signalled roundabouts

We have considerable expertise in all work associated with signalled roundabouts. The combined experience of our team goes back to the first ever fully signalled roundabout in Nottingham in 1978, and more recently includes the first two signalled roundabouts in New Zealand in 2008. During these 30 years our team members have worked on more than 100 junctions of this type, and have a unique portfolio of techniques for getting the best possible results.

Our full range of services for signalled roundabouts includes the following:

• Lane Structure and Spiralisation. The spiral pattern of lane to lane movements is key to any signalled roundabout. We use LinSig to test and manipulate spiral layouts with lane flows fully allocated to ensure best outcomes.
• LinSig Model Completion. The LinSig spiral layout and lane flows are a major part of the modelling to which traffic signalling is added. The signal timings are then optimised in LinSig for coordination and maximum capacity.
• Transyt Modelling. If required, we can replicate the LinSig results as a Transyt model. For the same geometric layout, modelling assumptions, and signal timings, LinSig and Transyt give the same results.
• Pedestrians and Cyclists. Signals at roundabouts can provide many options for controlled pedestrian and cycle routes. Making this extra provision can significantly enhance the benefits of schemes.
• Geometric Design. The spiral pattern of lanes and the presence of signal control are key to achieving the best geometric layout. We are well placed to produce both concept and more detailed design drawings.
• Signal Design and Operation. A full range of services is available. This includes specialist advice on implementation, including controllers, UTC/CLF plan timings, or MOVA enhanced control.
• Commissioning and Follow-up. Signalled roundabouts often require particular attention during the early days of operation. We have extensive experience of this in the UK and abroad.