Bollards have a bad reputation. They are considered dangerous for cycling and indeed many people get injured when they hit one, but bollards also have a very good side. They can regulate the traffic volumes in areas inside and outside the cities. This prevents rat running and increases the safety for walking and cycling. It also improves an area’s liveability, even more so when automatic retractable bollards are used.
With out of the ground rising bollards the city can be divided. This leads to areas that only residents or people with a business in that certain area will enter. Eliminating through traffic is a very good measure to improve the living environment of a residential area. It can also make a shopping area more attractive to people. Almost all bollards can be lowered in some way (usually with a key) to let emergency services pass the bollard when that is necessary.
When bollards are automatically retractable that can be done in a very easy way. That makes those bollards very suitable to filter traffic. Most often to let buses pass, but also to let residents or other permit holders pass the bollard easily and quickly. Through traffic will not be permitted to lower the bollards and that means only a fraction of the traffic volume remains. Every time the bollard is lowered only one motor vehicle can pass. The bollards will then go up whether there is another vehicle trying to pass or not. This can lead to dramatic consequences but more on that later in this post.
Filtering traffic with bollards is not unique to The Netherlands (even in the UK there are some streets that have a so-called filtered permeability) but the scale of how often you find such bollards in The Netherlands may be exceptional compared to the rest of the world.
An especially ingenious form of diverter is the diagonal traffic diverter on a four-arm junction. Effectively this creates two loops. Motor traffic can only turn from one street to one of the side-streets. Driving straight-on or turning in the opposite side-street is made impossible, because of the line of bollards which is placed diagonally across the junction. And even that is not typically Dutch. There is an example in Portland (Oregon, USA).
These loops help create an area that is divided into compartments. We know this policy of ‘compartmentalisation’ from Groningen, where it was retrofitted in the 1970s, and Houten, where it was in the original town’s design from around the same time. Many cities and towns in The Netherlands have since adopted that successful policy. Combined with a speed limit of 30km/h, it creates neighbourhoods which are traffic calmed so well, that other – more expensive – measures to improve walking and cycling become unnecessary.
Filtered permeability is not restricted to the built-up area. Bollards can also be used to regulate traffic in the countryside. This can mean that smaller roads do not have to get separate cycling infrastructure, simply because the volume of motor traffic is so low. Especially when the speed limits are also kept low (usually 60km/h outside the built-up area), mixing cycling and motor traffic is not too dangerous.
You can achieve low volumes by only admitting residents, but there are other solutions too. A bollard near ʼs-Hertogenbosch can only be lowered once in every 45 seconds. That is not too long if you are the only vehicle waiting, a normal traffic light could require such waiting times, but if there are 4 or 5 vehicles waiting ahead of you in the morning or evening rush hour, it could become very annoying. The waiting times must be so long that taking the slightly longer main road becomes favourable over this shortcut on a small country road. So in the end only people who really have to be on the country road are using it.
As said in the introduction bollards do have disadvantages. Many people cycling hit them and a lot of injuries are reported caused by bollards. Motor vehicles hit the bollards as well. That causes high repair costs especially when retracting bollards are crashed into and damaged. There are lots of videos on YouTube of people severely damaging their vehicle when they are ‘launched’ by a rising bollard.
In my hometown of ʼs-Hertogenbosch, where the first automatic bollard – in the shape of a pyramid – was placed in 1994, the system with a dozen or so pyramids costs 250.000 Euro per year. On average vehicles crash into one of the bollards once a month leading to these high costs. Even when some of the pyramids were replaced with normal bollards, which are more resilient against crashes, the costs were still high. So ʼs-Hertogenbosch will do a trial to get rid of the automatic bollards. From 1 January 2016 all retracting bollards will be lowered and kept that way. If the trial is a success (meaning unauthorised vehicles will not go past them) it would save the city 100,000 euro per year just on maintenance costs. The residents were not too happy when this trial was announced. They fear motor vehicles driving around in circles again, which would effectively be the end of the traffic calmed area. But since it is a one year trial they did agree to it. It might just work. When The Netherlands tried to do something against parking on the sidewalks, practically the whole country was littered with bollards on those sidewalks in the 1980s. You no longer see them everywhere. After a generation of drivers got used to not being able to park on the sidewalks they didn’t even do it on sidewalks without bollards. They had been educated. Slowly the bollards were removed everywhere. Let’s hope a similar process may have happened with regard to respecting areas that are closed to general motor traffic as well.
If not, there is another way to prevent unauthorised vehicles from entering an area. Leeuwarden uses it in a street that is for buses only. It replaced retracting bollards with a camera. This camerea with license plate detection takes care of fines sent to every driver illegally entering the bus only street. That is a viable alternative to the often damaged and thus expensive retracting bollards, or is it? You can debate how effective the camera is. In one year Leeuwarden detected 5,732 vehicles entering illegally, about 1 per hour during the day. They all got a 140 euro fine, but the whole idea was that you didn’t want them in the area in the first place.
video with this week’s post: how to prevent rat running
Other alternatives – that do work – are narrow bridges and tunnels with only one lane for motor traffic. That lane can only be used in alternating directions, regulated by a signal. This leads to waiting times similar to that bollard that retracts only once every 45 seconds, which does scare away through motor traffic.
In short, bollards can be good to filter motor traffic and they can improve the conditions in an area, but they have down sides and they are not the only solution. So the Dutch keep experimenting with new and different techniques to keep their country livable.