The C-roundabout (cyclist roundabout) is a new multi-lane roundabout design (developed as part of a 2006 Land Transport NZ research project Improved multi-lane roundabout designs for cyclists) that aims to improve the safety of cyclists at multi-lane roundabouts and make multi-lane roundabouts more cyclist-friendly.
A C-roundabout was installed at the Palomino Drive/Sturges Road intersection in Auckland and was evaluated between 2008 and 2011 in terms of its safety, capacity, and the opinions of cyclists, pedestrians and car drivers.
The C-roundabout successfully reduced vehicle speeds to 30km/h, which is close to the speed of cyclists. This made the roundabout safer for cyclists, as well as for other road users. The installation of the C-roundabout at this uncongested site had little impact on capacity. It drew positive feedback from cyclists and pedestrians, but about half of the car drivers were not in favour of it. This could be expected as they may prefer a wider roundabout than the narrow C-roundabout
Another site (Margan Ave/Hutchinson Ave) was also reviewed and involved changing two approaches from wide single lanes to two narrow lanes, without altering the kerbs and with no reduction in design speed. The evaluation showed the capacity of a single-lane roundabout can be improved (almost doubled) at very low cost. However, the safety of the roundabout had decreased and a reduction in design speed was recommended to address this.
An important technical note specific to this report
Non-standard signs and markings, which do not comply with the Land Transport Rule: Traffic Control Devices (TCD) Rule, have been used in undertaking this research.
These unauthorised signs and markings should not be replicated unless the appropriate approvals for such trial processes are obtained from the NZ Transport Agency prior to using such non-complying devices on public roads. See Transport Agency Traffic note 10 – revision 3 – Trials of traffic control devices: guidelines(external link).