Sustainable Safety in action

The N470 is a main road that runs east from the Dutch city of Delft, connecting it with the city of Zoetermeer. It is 12 kilometres long between the junctions with the A13 motorway (bypassing Delft) and the A12 motorway (which runs between The Hague and Utrecht).

From Google Maps

From Google Maps

As can be seen from the map above, it is, effectively, a bypass of the town of Pijnacker, bending south around it. Before this road was opened in 2007, a large proportion of the motor traffic running between Delft and Zoetermeer would have passed through the town. Now all that motor traffic is far away from human beings. This applies both at the large large scale – the way the road is built away from urban areas – and also at the scale of the road itself, where, as well shall see in this post, human beings are kept completely separated from it.

This modern road has been built according to the principles of Sustainable Safety, or Duurzaam Veiling – the Dutch approach to road safety. This programme was only developed in the mid 1990s, so it is relatively recent, but it completely underpins the way roads and streets in the Netherlands, both old and new, are designed and built to maximise the safety of human beings. The N470 is an excellent example of these principles in action, and this post will look at them in turn.

Functionality

Perhaps one of the most important principles of Sustainable Safety, ‘Functionality’ means that every road and street in the Netherlands should have a single function – mono-functionality – and that every region should classify their roads and streets accordingly, either as a

  • Through road – for fast traffic, travelling longer distances, in large volumes. Motorways, trunk roads, bypasses, and so on. Roads humans won’t ‘engage with’, by design.
  • Access road – the ‘end destination’ for journeys – places where people live, work, shop, relax, and so on.
  • Distributor road – the roads that connect up the through roads and access roads.

Quite clearly the N470 falls into the ‘through road’ category. It is a road for transporting people from A to B; it is most definitely not a road that people will be exposed to in any form. There are only three junctions between the outskirts of Delft and Zoetermeer, all  turbo roundabouts around Pijnacker, which human beings cannot go anywhere near. It is effectively hermetically sealed away from the environment it is travelling through – walking and cycling are entirely separated, via underpasses, and even other roads are again grade-separated.

Here the N470 goes into an underpass to avoid any connection with a rural access road. From Streetview

Here the N470 goes into an underpass to avoid any connection with a rural access road at ground level. From Streetview.

Homogeneity

This principle applies to the mass, speed and direction of road users. Heavy objects should not share space with light ones; fast objects should not share space with slow ones; and objects should be travelling in the same direction. Differences in mass, speed and direction should be minimised as much as possible.

We can see these principles clearly in operation in the design of the N470 road. Perhaps the most obvious application of homogeneity is that light objects – human beings – are completely designed out of this road. They go nowhere near it. In fact the photograph below is about the closest you can get.

screen-shot-2016-11-02-at-08-43-48

The three junctions on this stretch of road – two at the end, and one in the middle – are all turbo roundabouts, and all have total separation between human beings and motor traffic.

The roundabout at the Delft end of the N470 has signs explicitly banning walking and cycling from the roundabout – but really nobody would choose to negotiate the roundabout at surface level on foot, because of a fast, convenient cycle road to the side, that bypasses it completely.

screen-shot-2016-11-02-at-08-43-13

The roundabout in the middle is another turbo roundabout, again negotiated by an underpass – or, perhaps more specifically, where the road has been built up on an embankment with a bridge.

screen-shot-2016-11-02-at-08-44-11

And the final roundabout at the Zoetermeer end is exactly the same, with two underpasses allowing people to negotiate the arms of the the roundabout, complete with noise barriers. As with the previous example the roads and roundabout have been built up high so that cycling remains at ground level, at the same level as buildings in the neighbourhood. These are bridges, more than underpasses.

screen-shot-2016-11-07-at-00-47-38

I did manage to scramble up the bank here to take a photo of the roundabout – narrow lanes with hard physical dividers, combined with heavy, fast traffic, means that this is not somewhere you would want to be on a bike.

screen-shot-2016-11-07-at-00-49-48Especially when you can bypass it, completely oblivious to the traffic overhead.

screen-shot-2016-11-07-at-00-50-50

But of course Sustainable Safety applies to all users of the road network, not just people cycling. The road is designed in a way to keep motorists safe too.

screen-shot-2016-11-07-at-00-57-49Perhaps most notable is the median between the two lanes, that prevents any attempts at overtaking. The speed limit on this road is 80kph (about 50mph) and that applies uniformly to all vehicles, from HGVs right down to small cars. Quite sensibly, if everyone is travelling at the same speed, there can be no justification for overtaking, and the design prevents people from even attempting to do so.

A couple of years ago the DfT raised the speed limit for HGVs on single carriageway roads from 40mph to 50mph, partially on the grounds that it would (allegedly) reduce the temptation on the part of some drivers to indulge in dangerous overtakes. But the Netherlands has solved this problem at a stroke by equalising the limit for all users at 80kph, and by simply banning overtaking altogether on this category of road (and physically preventing overtaking in new road design).

All Dutch roads of this type have a continuous solid line, forbidding overtaking, and an equalised 80kph speed limit

All Dutch roads of this type have a continuous solid line, forbidding overtaking, even if a median is not present – along with an equalised 80kph speed limit.

Overtaking presents an unacceptably high level of danger – it involves vehicles occupying the same space but travelling in completely the opposite direction, at great speed. The opposite of homogeneity! It is much safer to ban it, and to simply design it out of these roads altogether. On the N470 all vehicles are travelling in the same direction at all times, and at approximately the same speed. Overtaking conflicts have been removed, as have any turning conflicts, with no motor vehicles crossing the paths of other motor vehicles – because there are no junctions.

Another implication of the principle of homogeneity is that mopeds (which aren’t capable of travelling at 80kph in any case) are banned from these roads, and instead placed on the cycle path, alongside people walking, cycling and jogging. This makes sense according to the principle of homogeneity – their mass and speed is much closer to that of pedestrians and cyclists than it is to the vehicles on the road.

screen-shot-2016-11-02-at-08-44-18

Forgivingness

Another principle of Sustainable Safety is ‘forgivingness’, which implies pretty much what you would expect from the title. Essentially, mistakes by road users should not result in death or serious injury. Road and street design should account for the fact that human beings are fallible, and will inevitably make mistakes.

We see this principle reflected in a number of aspects of the design of the N470 road. The road lanes themselves are narrow, to help ensure that people do not exceed the 80kph limit, but there are large overrun areas on either side of the road, composed of a concrete mesh.

screen-shot-2016-11-02-at-08-43-52

Probably not very enjoyable to drive over, but if you do drift off the road, you won’t die.

Naturally, forgivingness also applies to people cycling. It lies behind the systematic removal of bollards from Dutch cycle paths, where at all possible. Bollards are not good things to crash into, and can cause serious injury and death. It is definitely preferable to have the occasional driver venturing (either mistakenly or deliberately) onto a cycle path than it is to have a permanent hazard on it, 24 hours a day, seven days a week. It also means that kerbs and other elements of cycling infrastructure should allow mistakes to happen, without serious consequences.

New cycle infrastructure in the city of Delft, with a forgiving, essentially crash-proof kerb

New cycle infrastructure in the city of Delft, with a forgiving, essentially crash-proof, kerb

And, of course, at a higher level, the fact that there aren’t any human beings outside of motor vehicles on the N470 road, or even near it, means that cycling is very safe. The fact that Britain persists with accommodating cycling on busy 60 or even 70mph roads is extraordinary by objective comparison – the consequences of errors and mistakes when you have such enormous differences in mass and speed in the same space will be deadly.

Trucks travelling at 80kph on the right; a father with children in a cargo bike, far to the left. These two should not be combined, for very obvious reasons

Trucks travelling at 80kph on the right; a father with children in a cargo bike, far to the left. These two should not be combined, for very obvious reasons

Predictability

A better way of expressing ‘predictability’ would be ‘instantly recognisable road design’. The users of a road or a street should understand how they are expected to behave, from the appearance of that road or street. The design should be unambiguous. For instance, if you want motor vehicle users to travel at 20mph, the road or street should look like that, and it should make the majority of users travel at no more than that speed.

From the photographs in this post you won’t need me to tell you that the appearance of the N470 will obviously inform its users that it is a through road! There are no junctions; no interactions with non-motorised users; a median; and a design that suggests a speed of 50mph or so. As already mentioned, the design of the N470 should make users travel at or around this speed – the speed limit should be self-enforcing. Design should lead behaviour – we should not expect people to do unnatural things.

Conclusion

In a nutshell, Sustainable Safety is really about a strategic separation of fast, heavy objects from slower moving, lighter ones, across an entire country, both along roads like the N470, passing through rural areas, but also in urban areas. It is universal.

It is noteworthy that there are multiple cycle routes between Delft and Zoetermeer, all of them completely separate from the road network. Some parts of these are shown below. These cycle routes pass through the places where people actually live and work, while the motor traffic is shielded away from human beings. All these routes are more direct than the N470, or alternative driving routes on the motorways.

The cycle route in and out of Delft

One of the cycle routes between Zoetermeer and Delft – this one the closest to the N470, as it passes through a Delft suburb. The path runs directly through, and is connected to, this residential area, providing quick and easy access to housing, and on into the city centre.

Another route between Delft and Zoetermeer, as it passes under the A12 motorway.

Another route between Delft and Zoetermeer, further to the north, as it passes under the A13 motorway. This is an access road for motor traffic for the properties along it, but it becomes cycle-only as it goes under the motorway. Note the noise barrier. This is a peaceful, safe neighbourhood, with a cycle route running through it.

And another route between Delft and Zoetermeer - this one an access road (connecting to a small number of properties) that only permits driving in one direction.

And another route between Delft and Zoetermeer – this one an access road (connecting to a small number of properties) that only permits driving in one direction.

So despite the name, Sustainable Safety is not just about safety, but also about creating more attractive and more pleasant places for people to live, work, shop, and relax. People can still drive, of course, and with great ease, but their journeys will be separated to the greatest possible extent from human beings. It is a bold and ambitious project, but one that, despite only being a few decades old, has had dramatic and impressive consequences. We should be paying close attention.

 

You can read more about Sustainable Safety in a number of places –

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20 Responses to Sustainable Safety in action

  1. Correction. This is a distributor road. You can tell by the dashed white line on the outer edges, the fact that there are roundabouts at all and the lack of a raised metal or concrete guardrail along the centre of the roadway. There is also no autowegen or motorway sign. You also said that the speed limit is 80 km/h, that is not supposed to happen with through roads.

    Through roads have grade separated junctions, a full raised divide with a guardrail between the two directions, a hard shoulder and a speed limit between 100 and 130 km/h, only in exceptional situations is it ever reduced.

  2. Andre Engels says:

    Your statement that there is only one junction between the two motorways is incorrect. There is one in Delft, three near Pijnacker and five in Zoetermeer. Furthermore, four of the Zoetermeer ones are ‘normal’ junctions (the map did not show whether they had traffic lights), the other ones, apart from the Turbo roundabout you mention, seem to be normal roundabouts.

  3. Andy Stow says:

    I’m curious whether there is a speed minimum on a road like this, and whether any slower vehicles would use it. For example, could a farm tractor use the road, and if so would cars and motorcycles be expected not to overtake even if it were going 25 km/h?

  4. Bmblbzzz says:

    The Netherlands does seem to be a great proponent of the concept of roads as places in themselves. Not in the sense of ‘place-making’ or ‘shared spaces’ but roads like motorways which, instead of taking you from one place to another, function in some ways as a destination in their own right.

    Which leads me on to wondering about services and rest areas on these roads. Do the Dutch like to have many, frequent but simple and free to use, rest areas – really separated lay-bys with picnic tables and maybe a burger van – like the French and to an extent the Germans, or do they have infrequent but more substantial service areas, like the British? Or something else?

    • Jitensha Oni says:

      A good question. It’s a small country – about the size of Wales, though Wales would be a bigger if flattened out! Anyway, when we lived there, we tended to use the through N and A roads/motorways to get somewhere that wasn’t flat, as did many of our Dutch neighbours. Stopping for a picnic on the A12 etc wasn’t really a consideration (unlike some stops in the UK). Beautiful though Dutch land- and skyscapes are, you wouldn’t want to appreciate them from a main road, since there were so many other options. Service areas tended to be ‘functional’. Mark’s analysis is very focused on a through route (I agree with his designation despite the actual detailed design) – if you wanted to cycle for a nice trip (or even for speed) from Delft to Zoetermeer this would not be the route you would take.

      Therefore, to expand the point, for me, what Mark is showing is that even where the actual route is a bit meh, in the Netherlands, you’ll get the same attention to Sustainable Safety detail as if it were, for example, here:

      https://goo.gl/maps/XC8RBeUHbtv

      • Bmblbzzz says:

        I don’t think the landscape is a factor. Service areas, lay-bys, ‘aires de rest’ (spelling could be dodgy there) are primarily for drivers to have a break (and in the larger ones, to buy fuel etc).

    • Verfmeer says:

      The Netherlands is small enough that you can usually drive from one end to the other without needing a rest. It also lies at a corner of the European continent. This means that there is very little international through-traffic if you compare it to Germany or France. Traffic from Belgium to Germany usually only uses the A76(E314) and the A67(E34). Even from Brugge to Oldenburg you use the A67, driving in the Netherlands for only 77km: https://goo.gl/maps/irUeVmQwvMn. Since fuel is cheaper in Belgium and Germany there is no reason for big rest areas like there are in Luxembourg either, so from a car poin of view we only need a few rest areas.

      The point is different for cargo trucks though. The port of Rotterdam is the biggest port of Europe, and around 30% of its containers leave or arrive at the port via the road. We also produce lots of fruit, vegtables and flowers, which need to arrive fresh at their destination, making it impossible to transport them with trains or ships. European law demands that truck drivers take regular breaks. Since there are so many of them, we need a lot of parking room for them. This is made worse by German labor laws that forbid truck driving on sundays and holidays. At those days the rest areas overflow with trucks and they often park on the hard shoulder as well.

      This cargo problem is something nobody expected 30 years ago, when many rest areas were closed. Especially the unmanned ones, without fuel station or restaurant, were often only used by drug dealers, prostitutes and criminals. Several times the bodies of murder victims were found at such rest areas. The remaining rest areas usually contain of a fuel station, truck parking, small car parking (for toilet visits and technical checks). A few also have a hotel-restaurant.

      The fall of iron curtain and the growth of the end of border controls caused the amount of trucks to explode, and increased the demand for truck parking space. A new private company is building truck stops near exits on the A1 and A37, creating more parking space. The one at the A37 is now in use, but I don’t know exactly how well it’s doing.

      But to come back to your question. In the 10 years I’m driving I’ve only used a Dutch rest area a few times. One time for checking my cargo (I was driving a van) and few more times for toilet visit or dinner.

      • CyclinginEdmontonfromtheEyesofaTeen says:

        Looks like the Europeans are underusing their capacity of railway lines for cargo movement. You have some canals, especially in the Netherlands, and some good navigable rivers like the Danube from Switzerland to the Ukraine or Rhine, but most rivers are not intended for transport. Especially with the increased capacity that the electronic automatic control of trains offers, it’s surprising that you transport most cargo by truck.

  5. Pingback: Sustainable Safety in action

  6. Katrina says:

    I’d agree that sustainable safety would not be achieved if overtaking still exists. I mean, I myself am a victim of overtaking and it’s certainly not a pleasant experience. It’s safe to completely ban it to ensure the safety of all travelers.

  7. Mike says:

    Thank you for your comprehensive and fascinating article. I shall store away some of the main points for my next conversation with our County Councillor. In fact I’ll ask him to read it.

  8. yorksranter says:

    How does this differ from the now discredited Traffic in Towns concept, which was all about segregating cars and pedestrians?

    Also, I recognise some of the design from a suboptimal experience I had the other day. I was trying to walk from Den Haag-Ypenburg station to a hotel about a kilometre away. Leading away from the station was a nice Dutch footpath/cycleway separated from a distributor road by landscaping. On the other side of the road, the pavement ended, presumably where it transitioned from an access to a distributor.

    But my destination was on the other side of the road! And presumably because it lay in the cars-only zone, there was no way to get across other than running across something like your 3rd photo.

    • Yes, it is essentially derived at root from Buchanan’s ideas. Day-to-day human activity does not mix well with motor traffic, and it is far better to keep the two separated as much as is possible.

      If you had problems crossing a particular road, that is obviously a design failure, not a problem with the concept itself.

      • Mark Williams says:

        The UK highway `industry’ interpretation of the very same report is do as much as possible to simply discourage the day-to-day human activity—`guard’ rails and staggered crossings if you can’t altogether avoid having footways, `all-purpose’ MOATs which virtually nobody would want to use without a motor vehicle, don’t facilitate cycling because it will have died out by the 21st century, etc. I doubt anyone has ever managed to persuade them that this is anything other than current state-of-the-art thinking, let alone discredited.

  9. Pingback: Principles of Sustainable Safety in the Netherlands | Vision Zero UK

  10. This elaborate mode how to handle the flood of motor traffic reminds me of the special Dutch skills of dealing with water masses as their country in parts is located beneath sea level.

    I am Holsteiner and live in Hamburg. In Hamburg and on our Holstein westcoast the Dutch are very famous for their skills handling the always present flood. In further times Dutch were hired with special benefits in order to fix parts of the coastlines. For example Friedrichstadt in Holstein, where the rivers Treene and Eider meets the Northsea, looks like a little Dutch town, with Dutch townhouses and ‘grachten’.

  11. CyclinginEdmontonfromtheEyesofaTeen says:

    I know that many rural roads in my area are 8-9, usually 9, metres wide, and it would be from a Dutch perspective, easy to show how it could be a better design. For access roads, narrow to between 3 and 6 metres and if it exceeds 4.5 metres, add in dashed lines on either side as required, and divide the remaining space equally in half and use it as a clear zone and plant trees on either side of the road 1.5-2.5 metres back, works well.

    And the same width is also used for many roads that should be distributor roads as well. On 8 metre wide roads, use .4 metres to create that edge strip with a dashed line and rumble strip, use 3.1 metres for each traffic lane, and rip up the central 1 metre or use a double solid painted median with a rumble strip in the middle and post the speed limit to 80 km/h, although on undivided roads you should set it to 70. On 9 metre wide roads, just rip up more of the asphalt in the middle to create a wider median.

    Even primarily highways could work. 10 metre wide roads are normal for 100 km/h rural main roads, so 3.25 metre wide lanes, 1 metre wide shoulders, 1.5 metres of space in the middle as a painted or grass buffer (the latter as a result of ripping up the asphalt), and string up some high tension cable barriers (and close off intersections appropriately) and boom, you’ve got a sustainably safe through road. For 13 metre wide roads (3 metre shoulders and 3.5-3.7 metre wide lanes), then simply use a third lane that alternates and is used as the passing lane and narrow the median area to 1.25 metres. It’s quite simple really.

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