C-Roundabout

Author: Duncan Campbell The Duncan

The C-Roundabout is a new type of multi-lane roundabout developed in New Zealand in 2005, originally for the sole purpose of catering for cyclists. It was developed as part of the New Zealand Transport Agency (NZTA) research programme [1] [2], and was concurrently a thesis submitted for completion of a Masters degree (civil engineering) by Duncan Campbell.

Many cyclists find big roundabouts daunting to ride around, and can also suffer much higher crash rates than at traffic signals. That's not to say that multi-lane roundabouts are death-traps for cyclists, but they can be at the very least a deterrent to novice riders. Governments are trying to encourage more people take up cycling after all, for both health and congestion reasons.

Roundabouts are by the way a much safer form of intersection control than traffic signals and will suffer far fewer injury crashes, although you may get as many or more minor fender-bender type crashes. This is simply because of he fact that much higher collision speeds are possible at traffic signals, compared to a well designed roundabout.

However even though roundabouts are clearly the overall safer form of intersection control in terms of injury crashes, some city councils in New Zealand are more concerned with catering for pedestrians and cyclists so are instead installing traffic signals. Conventional multi-lane roundabouts can take up a lot of room so can be expensive to install, are trickier things to design, and traffic behaviour can be less predictable than signals. This is where the C-Roundabout fits in quite well - it can be built in a compact area and if designed with lower vehicle speeds in mind can be safer for both pedestrians as well as cyclists. Basically it requires larger vehicles such as truck or buses to straddle traffic lanes and for car drivers to discern that they have to keep clear of these vehicles.

Several C-Roundabouts have been built in Waitakere City to date, successfully for the most part. A NZTA research project that reviews their operation is currently being submitted for publication and hopefully should be available early 2011. [3], [4]. This review includes colecting feedback from drivers, cyclists and pedestrians. In general a high proportion of drivers do not like them because they squeeze you closer to traffic in adjacent lanes, and would much prefer a conventional roundabout instead. Cyclists certainly prefer the C-Roundabout though, and pedestrians also.

Note this page is at the moment in its very draft stages so hope to clean it up a bit. In addition, I will try to put some links to video footage which I will try to make available. The Duncan 06:54, 10 September 2010 (NZST)