Monday 18 June 2012

Central reservations enable cyclists and pedestrians to cross safely

Where cyclists or pedestrians must cross a road which is used by an appreciable number of motor vehicles, central reservations make a huge difference to safety. They allow the cyclist to cross just one stream of traffic at once, which is moving in one direction, before making a second decision from the centre of the road before crossing again.

Of course, such a reservation needs to be adequate in size. The crossing shown above, in a residential area in Assen by the local shops, allows two cyclists travelling in each direction to pass each other, and is long enough for a bicycle with trailer to stop safely in the middle. it also has a completely separate crossing for pedestrians, and of course both the cycle and pedestrian paths on both sides of the street. The speed limit for cars is 50 km/h (30 mph).

Here is another view of the crossing:

Open in Google Maps - note that cyclists don't suffer from a "pinch" effect due to cars because there are separate cycle-paths either side of the crossing.

When we first moved to Assen, there
was no central reservation at this
crossing. Image from a leaflet
explaining the change
This is an example of a crossing which works extremely well for cyclists, but it is not in any way an unusual or unique design. It's actually strikingly normal - there are so many crossings like this in Assen that I couldn't possibly count them. You need look no more than a hundred metres to the South from this one to find three more which are similar (see them here on Google Maps).

However, that this is very common doesn't imply that such crossings have existed forever. Actually, this one was retrofitted quite recently.

Back of the same leaflet
explaining what was
being done to improve
safety. Particularly
aimed at school children
Note five features on and around this crossing which make motorists slow down. Firstly, the shape of the crossing requires that motorists must decelerate and change course to go around it. Secondly, the width of the lanes either side of the central reservation is narrow which makes maneuvering difficult at speed. Thirdly, the road is narrow and there is no central white line. This makes motorists less sure of their position on the road and further reduces speed. Fourthly, the speed limit is 50 km/h (30 mph) on this street, which provides access, and 30 km/h (18 mph) on surrounding streets. Fifthly, there is also a pedestrian zebra crossing here for which motorists must stop if a pedestrian is crossing. Cyclists don't have priority in this case, but often receive it anyway.

The requirement that motorists have to swerve could be dangerous to cyclists due to a pinching effect if cyclists were on the street but because there are parallel cycle-paths on both sides of the street there is no danger at all.

See also videos showing the same crossing in use by hundreds of school children.

This can be seen as something which is easily "lost in translation" when implemented elsewhere because while the same concept might appear elsewhere, the implementation is completely different. For example, here's the same concept as implemented in Cambridge, UK:

Crossing of Madingley Road in Cambridge, UK. This is one of several roads in Cambridge which are unpleasant to cycle along and which can be difficult to cross safely by bicycle. We used to do this with our children, but this made us very much the exception as most people would not see this as a safe thing to do with their children. It's important for campaigners to realise that they are part of a self-selected group. Conditions like this are a reason why keen cyclists stop when they have children.
The example shown at the top of this blog post from Assen is on a relatively minor street with a slow speed limit and a significant but not enormous flow of vehicles. Those are the conditions in which  a crossing, if built to a high enough standard, can work well. However this Cambridge example is on a major arterial road, one of the busiest in Cambridge. This central reservation is too small in both dimensions. It does not slow traffic because the lanes either side of the reservation are too wide and it doesn't cause motor vehicles to change course, but the central reservation is also too narrow. Only one person can use it at a time and it can't be used if towing a trailer. It also doesn't feel safe because there is not much separation from high speed traffic. There's also no separate provision for pedestrians and neither pedestrians nor cyclists are prioritised at this crossing.

What's more, the speed limit here is much higher than that of the Assen example, at 40 mph (64 km/h) and this is a major arterial road into Cambridge so there are usually far more cars driving here than you find at the equivalent looking crossing in Assen.

When we crossed at this point with our children it was difficult to accompany them and cross the road safely. What's more, when I pulled a child trailer across this junction it didn't fit, so I had to make the crossing in one step.

It's an example of something extremely inadequate being installed in completely the wrong situation. The closest equivalents we have in Assen would be this or this.

Another view of the crossing of Madingley Road. It's similar to Huntingdon Road a little further North and many other roads in and around Cambridge. These are part of the reason why Cambridge's cycling is limited to a demographic groupView Larger Map

If your only reference to good infrastructure design comes from books, websites and looking at Google Maps, then it is very easy to misinterpret what is seen on the ground in the Netherlands. This is why it is important that planners from English speaking countries should see for themselves what good infrastructure actually looks like, and see it in the country which has the best standards. Referring only to what is in, for example, the UK can only result in copying from bad examples. It is to try to help to prevent this problem that we organise study tours.

See other examples of ideas "lost in translation", enabling of crossing the road, and perhaps most important, examples of what works in the Netherlands.


Unknown said...

A little inconsistency in your article: above the streetview image you say that the speed limit is 50, below it is 30.

David Hembrow said...

Thank you Arjen. I've fixed the inconsistency in the article.

Anonymous said...

Excellent post David. You could also add a fifth design feature that makes motorists slow down - the presence of a zebra crossing, which gives pedestrians priority.

David Hembrow said...

aseasyasridingabike: You're right, that helps too. I've added the fifth design feature to the description.

Rob said...

if only your study tours were compulsory training for everyone at the DfT, local councils, traffic engineers and transport planners the UK might just get somewhere. as an ex-resident of Amsterdam i really miss the amazing cycling provision all over the Netherlands.

David Hembrow said...

Rob, to want to come on the tour requires a people to question what they have and actually want things to change for the better. Sadly, the overwhelming majority of your representatives, planners, DfT officials, we can even go further and include most campaigners in Britain, are simply not interested in doing this.

None of the people you suggest have ever shown the slightest interest so far save for one planner and a couple of cycling officers who came of their own accord. More would be very welcome, of course.

However, this should perhaps not be too surprising given that we recently found out that even the Chief Executive of the CTC for 14 years didn't think it worth his while to visit the Netherlands until two weeks ago when he'd already left that job to take up running the ECF instead.

Can any real progress be made when jobs such as this are filled by people with so little desire for improvement ?

Dennis Hindman said...

Interesting take on how median waiting areas for pedestrians and cyclists should be designed. I would have never considered that there should be room for a bicycle plus a trailer that typically would be pulling children. Los Angeles is scheduled to start working on cycling infrastructure for residential streets, which the city will call bicycle friendly streets. These central reservation waiting areas are something that the traffic engineers are considering, along with installing traffic signals to make it easier for pedestrians and cyclists to cross busier streets.

Here's some interesting graphics posted on Time magazines website that puts the condition of transportation infrastructure in the U.S. into perspective. An improvement would seem to be to simply use some of the money that goes to the military towards improving the condition of the transportation infrastructure. But, currently, if the military spending was cut dramatically, the Republican Party would want to send that money back to the taxpayer and not spend it on anything else. The congressional house Republicans are currently trying to eliminate most federal funding for pedestrians and bicycling from the transportation bill. Most Democrat Party members and Senators do not agree with this and so there is a stalemate.

Koen said...

I notice that in the British situation children would be totally obscured by the enormous arrow signs on the reservation. Indeed, not cycle friendly.

christhebull said...

The issue with the Cambridge example seems to be that while it might have been built under the presumption that cyclists could use it, it obviously has the dimensions of a standard pedestrian island, ignoring the increased size of a bicycle compared with a standing pedestrian.

This would be like constructing a perfectly adequate taxi rank for four taxis, changing it to a bus stop, and wondering why only one bus could fit in the bay and any others were waiting in the main traffic lane blocking everyone else. Or even worse, like an architect building a passenger lift to access an underground car park when a larger car lift with a greater weight capacity is necessary...

Koen said...

A sixth feature could be the integrated speed bump at the point of the central reservation, something that is seen quite often in the Netherlands.