Thursday 11 August 2011

Roundabout with safe cycling facilities

The report above from SWOV in 2004 compares cyclist
safety of roundabout designs. This blog post recommends an
unsafe design.
Please read a later blog post which shows the safe design.
The design proposed in this guest blog post is not the safest possible. In fact, the design promoted in this post is known to be responsible for dozens of injuries each year in the Netherlands. This design causes seven times so many injuries as the best Dutch roundabout designs. Please see a later blog post which shows the safest roundabout design for cyclists.

A view at one of the more recently built roundabouts in the city of 's-Hertogenbosch in the South of the Netherlands. This roundabout came in the place of an ordinary four arm junction with traffic lights. When the city announced that the junction would be changed into a roundabout people had a hard time believing this would be possible at all. They thought there would not be enough space. But it proved to be very possible indeed. Traffic now flows very smoothly.

Interestingly enough Google Maps shows the before situation, but once you start StreetView it shows the current situation.

Before: a junction with traffic lights and separate cycle paths.
After: roundabout with separate cycle paths, the lights were removed. Note that this roundabout design is responsible for dozens of injuries per year in the Netherlands.
The waiting times for all traffic decreased at this particular junction. So it proved to be a good decision to change the junction into a roundabout. I have showed you another roundabout in 's-Hertogenbosch in an earlier post. There the priority for cyclists on Dutch roundabouts is also explained.

Update: It seems people are taking this design presented by a guest blogger as something to aim for. Please note that this is not the safest design of roundabout which is possible and we do not suggest copying the design shown in this blog post. The particular example shown here closely resembles a roundabout in Groningen to which we take people on study tours in order to see how NOT to design a roundabout. This relies too much on drivers being perfectly behaved. and on cyclists having eyes on the back of their heads.

Other posts on this blog show safer roundabout designs where cyclists either don't interact at all with cars on the roundabout or where they give way on those arms where there are interactions. These other roundabouts provide a better example for other nations to follow.


Paul Martin said...

Great clip, Mark. Thank you.

I noticed a few things:
- two cyclists going the wrong way (it would have been faster if they went the right way!)
- a tourist (?Australian) with a 'hybrid' bike and a oddly fast cadence!
- a rollerblader enjoying the infrastructure!

I only wish some of our roundabouts had this sort of treatment in Australia.

Most of them have NO provision for cyclists; some have bicycle lanes that terminate immediately before the entry (lethal) and those that have bike lanes on them require cyclists to give way to cars as they exit the roundabout... even if the cyclist is ON it! There is no priority or respect.

As a result, drivers treat roundabouts like racing track chicanes here... it's awful.

See here.

NIKDOW said...

I thought I read somewhere that in the Netherlands roundabouts are being phased out, as they are difficult to make safe.

Apparently not!

BG said...

Hmm...I like this, but the only thing that seems "safe" about it is the excellent training of Dutch motorists. The cars _must_ yield to the bikes. In this video, they consistently do -- but what happens in a country (Australia, U.S....) where they probably won't?

Anonymous said...

This isn't even the recommended configuration (probably because of lack of space). The most common design has about 5 metres (a car's length) between the roundabout and the cycle crossing. That way, a car can leave the roundabout and wait for crossing cyclists without obstructing the flow of traffic.

@NIKDOW: Surely not, they're building loads of them. The very reason they're being built is the roundabout's impressive safety record.

@Paul Martin: What strikes me as odd about the way roundabouts are done in the UK, the US and Australia is the angle at which the roads meet the roundabout. A lot of the time, the roads are angled such that you can enter and leave the roundabout without slowing down. Late at night on an empty road, you'd be able to power straight through. Dutch - and more generally continental European - roundabouts are designed such that you have to make a sharp (slow!) turn both when entering and leaving the roundabout.

@BG: They're not yielding just because it's in the road rules, the cyclists have clearly marked priority (the triangle markings on the road surface, and at most roundabouts also with signs) - Australian and British motorists still stop at yield lines and red lights, don't they?

christhebull said...

Unfortunately roundabouts in the UK can be very problematic for cyclists. Many of them allow traffic to enter the roundabout without deviating significantly. The largest often have multiple circulatory lanes which drivers can and will move between, even where the markings are "spiralised" so this is not needed. (Dutch "turbo roundabouts" sometimes found on major roads do not allow lane changing or U-turns, which means they have a higher capacity) Also quite common are the painted mini roundabouts used in quieter or more constricted locations. While less problematic for cycling, they can be driven over in a straight line and therefore have limited effectiveness as "traffic calming".

Some junctions, of course, have roundabouts with traffic lights on them as well. The Hogarth Roundabout with its "temporary" flyover from the 60s is an example of this. Of course, there are no cycling facilities and pedestrians are directed into an underpass.

This Dutch roundabout has traffic lights, but because it is a through-about with a road through the centre, this is rather necessary.

Anonymous said...

christhebull: Actually, that site and any other you might encounter that do have traffic lights (Utrecht has a few) aren't real roundabouts, they're traffic circles. The crucial difference is the rule that one should yield to traffic already on the roundabout, whereas vehicles on a traffic circle should yield to the right (traffic joining the traffic circle) as normal. A better example is this in the same town as the one you linked to. Note the one-way sign instead of a roundabout sign.

Neil said...

> Australian and British motorists still stop at yield lines
> and red lights, don't they?

err, not always. No Seriously a yield line (give way in UK) does not mean you have to stop and so a motorist will not if they don't need to. In UK with a cyclist they are far more likely to ignore or make a mistake about the need to stop.

Slow Factory said...

I guess there is not much pedestrian traffic here BUT anyway I am curious how pedestrian crossing times were affected.

Christoph said...

The safest way through roundabouts for cyclists is the "Swiss way" described here:

Willeke said...

I do not agree that this Swiss idea is good, even less the best.
It is what we Dutch would think of as an old fashioned roundabout without bike infrastructure, combined with taking the lane, which is something we do not agree with at all.

Slow Factory said...

Christoph, do children and inexperienced cyclists feel safe going through those kind of roundabouts AND are they safe going through them?