Difference between revisions of "C-Roundabout"

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Author: Duncan Campbell [[User:The Duncan|The Duncan]]
 
Author: Duncan Campbell [[User:The Duncan|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 [http://www.nzta.govt.nz/resources/research/reports/287/] [http://www.ipenz.org.nz/ipenztg/conf05/papers/5%20CAMPBELL.pdf], and was concurrently a thesis submitted for completion of a Masters degree (civil engineering) by Duncan Campbell.
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[[File:Crbt1.jpg|400px|left]]
  
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.
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The C-Roundabout is a new type of multi-lane roundabout developed in New Zealand in 2005, originally as means of more safely catering for on-road cyclists.  It was developed by Duncan Campbell and Ivan Jurisich of Traffic Engineering Solutions Ltd [http://www.tes.net.nz/] as part of the New Zealand Transport Agency (NZTA) research programme [http://www.nzta.govt.nz/resources/research/reports/287/] [[Media:Crbtaustroads2006.pdf]], and was concurrently the topic for a thesis submitted for partial completion of a Masters degree (civil engineering) by myself.
  
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 crashesThis is simply because of he fact that much higher collision speeds are possible at traffic signals, compared to a ''well designed'' roundabout.   
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Many cyclists find big multi-lane roundabouts daunting to ride around, and can also suffer much higher crash rates than at traffic signals[http://www.nzta.govt.nz/resources/research/reports/287/]Although multi-lane roundabouts are not necessarily death-traps for cyclists, they can be at the very least a deterrent to novice ridersThe New Zealand government is trying to encourage more people take up cycling for both health and congestion-relief reasons, so this matter is of some concern.
  
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.     
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Well designed roundabouts are a safer form of intersection control for vehicle drivers than traffic signals and should suffer far fewer injury crashes involving these users, particularly so for junctions with greater than three adjoining legs [http://www.hardingconsultants.co.nz/ipenz2011/downloads/Campbell__Duncan.pdf].  This is simply because much higher collision speeds are possible at traffic signals compared to a ''well designed'' roundabout.  However, many city councils in New Zealand are more concerned with catering for pedestrians and cyclists and are instead installing traffic signals which does not necessarily align with the objective of reducing injury crashes on our roadsOther reasons may include: conventional multi-lane roundabouts can take up a lot of room so can be expensive to install; roundabouts are generally trickier things to design well; and traffic behaviour can be less predictable than at traffic signals.  This is where the C-Roundabout fits in quite well - it can be built in a compact area (i.e. cheaper) and if designed with lower vehicle speeds in mind can be safer for both pedestrians as well as cyclists.  This is achievable because it requires larger vehicles such as truck or buses to straddle traffic lanes, and car drivers are expected to discern that they are to keep clear of these vehicles (appropriate signage can assist).     
  
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. [http://cyclingconf.org.nz/system/files/NZCyclingConf09_5A_CampbellJurisichAsmus_Roundabts.pdf], [http://cyclingconf.org.nz/system/files/05a4-Duncan-Campbell.pdf].  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.
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Several C-Roundabouts have been successfully built in Waitakere City since 2008.  A NZTA research project that reviewed their operation is currently being submitted for publication and hopefully should be published early 2012, and in May 2011 some of the findings were presented at the International Roundabout Conference in the United States  [http://www.teachamerica.com/RAB11/RAB1122Jurisich/player.html] [http://www.teachamerica.com/RAB11/RAB11Papers/RAB1122Jurisich-0070.pdf].  This review included evaluation of vehicle speeds and road user behaviour and collecting feedback from drivers, cyclists and pedestrians.  In general a reasonably high proportion of car drivers do not like them because they squeeze you closer to vehicles in adjacent lanes, but cyclists and pedestrians certainly prefer the C-Roundabout because traffic speeds are lower and cyclists are better able to 'claim the lane'.
  
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. [[User:The Duncan|The Duncan]] 06:54, 10 September 2010 (NZST)
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One example includes the Seymour Rd / Parrs Cross Rd intersection in Waitakere, a brief clip of its operation during a morning peak is shown at : [[http://www.youtube.com/watch?v=By9Yve0KeVA]].

Latest revision as of 18:39, 16 January 2012

Author: Duncan Campbell The Duncan

Crbt1.jpg

The C-Roundabout is a new type of multi-lane roundabout developed in New Zealand in 2005, originally as means of more safely catering for on-road cyclists. It was developed by Duncan Campbell and Ivan Jurisich of Traffic Engineering Solutions Ltd [1] as part of the New Zealand Transport Agency (NZTA) research programme [2] Media:Crbtaustroads2006.pdf, and was concurrently the topic for a thesis submitted for partial completion of a Masters degree (civil engineering) by myself.

Many cyclists find big multi-lane roundabouts daunting to ride around, and can also suffer much higher crash rates than at traffic signals[3]. Although multi-lane roundabouts are not necessarily death-traps for cyclists, they can be at the very least a deterrent to novice riders. The New Zealand government is trying to encourage more people take up cycling for both health and congestion-relief reasons, so this matter is of some concern.

Well designed roundabouts are a safer form of intersection control for vehicle drivers than traffic signals and should suffer far fewer injury crashes involving these users, particularly so for junctions with greater than three adjoining legs [4]. This is simply because much higher collision speeds are possible at traffic signals compared to a well designed roundabout. However, many city councils in New Zealand are more concerned with catering for pedestrians and cyclists and are instead installing traffic signals which does not necessarily align with the objective of reducing injury crashes on our roads. Other reasons may include: conventional multi-lane roundabouts can take up a lot of room so can be expensive to install; roundabouts are generally trickier things to design well; and traffic behaviour can be less predictable than at traffic signals. This is where the C-Roundabout fits in quite well - it can be built in a compact area (i.e. cheaper) and if designed with lower vehicle speeds in mind can be safer for both pedestrians as well as cyclists. This is achievable because it requires larger vehicles such as truck or buses to straddle traffic lanes, and car drivers are expected to discern that they are to keep clear of these vehicles (appropriate signage can assist).

Several C-Roundabouts have been successfully built in Waitakere City since 2008. A NZTA research project that reviewed their operation is currently being submitted for publication and hopefully should be published early 2012, and in May 2011 some of the findings were presented at the International Roundabout Conference in the United States [5] [6]. This review included evaluation of vehicle speeds and road user behaviour and collecting feedback from drivers, cyclists and pedestrians. In general a reasonably high proportion of car drivers do not like them because they squeeze you closer to vehicles in adjacent lanes, but cyclists and pedestrians certainly prefer the C-Roundabout because traffic speeds are lower and cyclists are better able to 'claim the lane'.

One example includes the Seymour Rd / Parrs Cross Rd intersection in Waitakere, a brief clip of its operation during a morning peak is shown at : [[7]].