Rising traffic volumes have put strain on several low-risk residential intersections around Dunedin, as well as on many which were already a priority for upgrades. Limited visibility and acute approach angles posed further safety issues at some of these intersections. Dunedin City Council (DCC) therefore wanted to improve the safety and efficiency of these intersections, but the capital cost of installing standard permanent upgrades across all of them would be cost-prohibitive. In order to improve multiple intersections, upgrades therefore needed to be light and low-cost.
DCC installed trial roundabouts at 11 unsignalised intersections to test roundabout sizes and layouts. As well as enabling a smaller layout than usually designed for permanent changes, the trial format meant small changes on-site could easily be carried out. The changes included:
The changes were intended to improve safety by:
By making initial changes as a trial, the changes were likely to be better received by the public, as they can be adjusted or removed if they prove not to be functioning well. Following the initial roll-out, changes included adding speed humps to the central islands of those originally without, and installing reflective flexible bollards along the intersection medians and edges.
Before and after video data collection is ongoing and will be used to monitor road user behaviour at the trial sites. DCC received a lot of feedback, both negative and positive:
Lessons learned include that: