“Roundabouts are safer than intersections because they reduce the number of potential conflicts between road users and lower the driving speed. In the Netherlands, replacing a four-arm intersection by a roundabout is estimated to reduce the number of severe casualties by approximately 70%. The traffic flow is usually better on roundabouts than on intersections, and exhaust emission and noise decrease, certainly when compared with signalized junctions.”
|Potential conflicts on intersection types. |
cross roads | T-junction | roundabout
Cyclists generally have no priority on roundabouts outside built up (in rural) areas.
HistoryThere have long been roundabouts in the Netherlands. But they were large with only a small center island so cars could easily pass each other at high speeds. These old fashioned roundabouts were not very safe and because of the priority rules they were not particularly effective either. Under Dutch law all traffic on the roundabout had to give entering traffic –coming from the right– priority. This led to a standstill on the roundabouts when there was a lot of traffic.
|Old fashioned roundabout in 1960 in 's-Hertogenbosch, Netherlands|
clearly visible the lighter colored cycle lanes on which cyclists did have priority over motorized traffic exiting the roundabout
Since the speed of motorized traffic on a modern roundabout is so low (around 30kph/18mph), the city of Enschede started an experiment in 1990. They reasoned that with those speeds it would perhaps be no problem at all to give cyclists on a ring shaped cycle path around a roundabout priority over motorized traffic that enters and exits that roundabout. The experiment was successful and soon other municipalities followed. This led to differences in priority between different municipalities and confusion with road users. Confusion leads to unsafe situations so this was unwanted. The government initiated action to remedy this.
Who gets the right of wayAfter thorough investigations CROW (Dutch technology platform for transport, infrastructure and public space) finally came with recommendations to harmonize the dimensions and the priority rules on Dutch roundabouts in 1993. They were supported by the minister of transport, the provinces, most municipalities and organizations like VVN (‘Safer Traffic Netherlands’), ANWB (Dutch Motorist’s Union) and the Cyclist’s Union. The recommendations marked the end of the experimental phase of priority for cyclists on roundabouts in built up areas.
An underlying investigation showed how road users best understand who has priority:
1 by the so-called ‘shark teeth’ markings on the ground (which are more clear than traffic signs);
2 by having the color of the cycle path continue across the drive way of motorized traffic.
|Roundabout in 2011 in 's-Hertogenbosch, Netherlands|
with priority for cyclists on the separate cycle path around the roundabout
Note that this is not the safest roundabout design used in the Netherlands. This design is known to be responsible for dozens of injuries a year in the Netherlands.
By 2010 the recommendations were adopted by most municipalities. Cyclists did no longer have priority on nearly all of the rural roundabouts. But it is different for urban roundabouts: some municipalities refuse to adopt the recommendation even though they were repeatedly asked to change the priority on their roundabouts by even the minister of transport.
This could have to do with the fact that first investigations revealed that roundabouts where cyclists have priority were "slightly less safe" than those where they do not have right of way. However both situations are considerably safer than traditional cross roads junctions. Apart from SWOV (Institute for Road Safety Research) all the other institutes were therefore in favor of priority for cyclists in built up areas.
On VVN’s website this is explained: Although it is supposed to be safer for all cyclists to not have priority, Veilig Verkeer Nederland (Safer Traffic Netherlands) does not find this desirable. It would have negative consequences for the mobility of cyclists. Especially in built up areas cycling is to be preferred over driving. This should be reflected in the right of way.
Now that the rule has been in force for over a decade and all traffic users could get used to the priority rules, the Cyclist’s union sees a high and growing appreciation for these roundabouts. Interestingly cyclists also report a decreasing number of “near misses” and they give high marks for comfort.
The most important type of roundabout is the single-lane roundabout. It can handle 20,000 – 25,000 vehicles per day. With a steady arrival of vehicles, a roundabout can have a shorter waiting time than a signalized junction.
In general, the waiting time for cyclists and pedestrians is shorter on a roundabout, even without priority, than at signalized junctions.
When an intersection with traffic lights is replaced by a roundabout, the emission goes down by 29% for CO and 21% for NOx. The noise emission decreases in both cases.
 Information for this blogpost was gathered from the Factsheet Roundabouts from SWOV and websites from the Cyclist’s Union, VVN, Fietsberaad and other institutions.
Important note: Assumptions made by the author and other organisations about the safety of this roundabout design have proven to be incorrect in the light of actual crash statistics. While this roundabout design is safe for drivers, it has almost no benefit at all for cyclists over an un-signalled junction. What's more, it has been proven to cause seven times so many injuries as the safer Dutch roundabout design.
This post by Mark Wagenbuur also appears on his own blog.