Sunday 24 June 2018

Pushing e-bikes will not result in mass cycling

15-20 years ago the most common objections heard to the idea that better infrastructure was required to enable mass cycling came from people who promoted training of cyclists and vehicular cycling. It was claimed that if enough people could be trained to cycle amongst motor vehicles then no cycling infrastructure was required. Decades have passed and of course no such result was ever seen because the problems which faced people cycling had not been resolved. Meanwhile, those places which built better cycling infrastructure have seen improvements in cycling modal share. The calls for training and vehicular cycling have become much quieter in recent years, but similar calls are now being made for another related idea: That take-up of e-bikes will result in mass cycling despite conditions on the roads not having been improved. This idea has no more validity than the claims made 20 years ago.

If you take someone who is scared to cycle because of the danger of traffic and give them a bicycle they are unlikely to take up cycling just because they now have a bicycle. I pointed out years ago that "a shortage of bicycles was never the reason for the low cycling rate of London" but this applies worldwide. Millions of bicycles gather dust in sheds around the world because their owners don't find riding them on the local streets to be appealing at all.

If you take someone who is scared to cycle because of the danger of traffic and give them a bicycle with a motor, the reaction is very likely to be the same. The source of the fear has not been addressed by adding a motor to the bicycle so they'll still be unlikely to take up cycling.

Dutch parents let their children cycle right into city centres
because it is safe to do so on cycle-paths, not because they
have motorised bicycles.
Parents who are not happy to see their young children ride bicycles on roads filled with motor traffic will be no more enthusiastic about them doing the same thing with a motor on their bike.

Pensioners who are currently scared to cycle on busy roads won't suddenly gain enthusiasm because someone has given them a motorised bicycle.

People with disabilities who use hand cycles or other mobility devices but can't travel far with them because they do not feel safe on the streets are not suddenly going to feel safe to put themselves in front of motor vehicles because they have been given a motor.

Proponents of e-bikes often point to studies which often don't say what they think they say.

A Danish study:
There's a Danish study which is sometimes claimed to show an "11% increase" in cycling due to e-bikes but of course the reality isn't quite like that headline. The study involved 120 people from a city of 61000 who volunteered to be part of a study about the potential of e-bikes. 80 took part in the after study analysis. Of those, 45% claimed they cycled more after they were provided with an e-bike (55% said they cycled the same or less). The 11% increase in cycling which was observed was within the 80 people who chose to take part because they were already interested in e-bikes. That some people who thought they wanted an e-bike turned out really to want an e-bike should surprise no-one. What's more, it's important to note that because these people lived in Denmark they were already in a country which has relatively developed cycling infrastructure and a relatively high cycling modal share because of that infrastructure. They have somewhere safe to ride their e-bikes. This is not a result which has any relevance to a country which does not have cycling infrastructure.

An American study:
There is also an American survey which is popular amongst e-bike enthusiasts, the National Institute for Transportation and Communities North American Survey of Electric Bicycle Owners NITC-RR-1041. A popular website article claims that this survey proves that "e-bikes are getting more people out of their cars". This initially seemed more interesting than the Danish study because it's a study from a place which has little to no cycling infrastructure and great increases in cycling were claimed. If those findings could be translatable to other countries which lack infrastructure that would be very interesting indeed. But I've now read the report and unfortunately there are many problems which arise from it. I will go into these problems below:

Note that while some website headlines are dramatic they're quite loosely connected with the report itself which uses more reasonable language. I suggest that it's important to read the report itself to understand what the survey was and what the results mean. Methodology affects results. The authors are candid and honest about the scope of their survey. They do not claim that it is impartial and nor do they claim that the results can be extrapolated to the population at large. This survey was supported by e-bike manufacturers financially as well as with "input, feedback and efforts on the project to make sure it was successful." The people surveyed were all people who already own e-bikes and over 80% of respondents had owned their e-bike for less than two years when they responded to the survey. We can therefore expect new owners' delight with their new purchase to be reflected in the results.

This survey of 1800 people targeted a self-selected group of people who were found "through e-bike blogs and forums, multiple social media platforms, manufacturer and retailers’ e-mailing lists, and cards left on e-bikes throughout the Portland, OR, area" and as such we can expect many enthusiasts amongst the respondents. The authors don't try to deceive but acknowledge the limitations of their survey. They admit that respondents were not selected randomly and that findings might not be representative even of the whole population of e-bike owners, let alone the population at large.

None of this is a criticism. The report authors are quite clear about what they've done and by presenting their data as they have, they have given an insight into North American e-bike owners. I do, however, criticise some of the websites which have published dramatic headlines based on the survey and some of the people who have taken those headlines and made yet more dramatic claims because the results of this survey have been taken out of context.

It should be noted that most of the e-bikes used by respondents to this survey are too powerful to be recognised as e-bikes in most countries. Only 6% of respondents have e-bikes on which assistance is available only up to the 25 km/h which applies for an assisted bicycle in the EU. 94% of respondents have e-bikes which are more powerful than that. i.e. most of these e-bikes would be classified as "speed pedelecs" in Europe - number plates are required and riders must wear helmets. While only 6% of respondents have the slower EU legal e-bikes, a greater number (7%) have bikes on which the motors are so powerful and can push their riders at such speeds that in Europe they couldn't even be speed pedelecs, but would have to be registered as motorbikes. As such, this study's application to many countries is already limited as it mostly concerns itself mostly with a completely different class of vehicle to that which we would recognise as a legal assisted e-bike in Europe.

The limitations of self-reporting are also exposed. While more than half of respondents claim to be of "very good or excellent health", only a quarter of respondents say that they do even 30 minutes of moderate exercise per day, as recommended widely as a minimum required for good health. 3/4 of e-bike owners do not take 30 minutes of even moderate exercise a day and therefore also cannot be cycling for 30 minutes a day. The most common maximum speed of assistance is 20 mph, suggesting that the distance covered even by most of the respondents who actually do take 30 minutes of exercise per day will be somewhat less than 10 miles (16 km) while most respondents will cover somewhat less distance than this. This puts the report's claim of an "impressive decrease in vehicle miles traveled" in some doubt.

Leading question: Why didn't you cycle before you
had an e-bike ? Choose from one of these answers.
Though the most common reason why people do not cycle is the fear of motor traffic, the multiple choice question which asked about why people didn't cycle before they got an e-bike did not include that as a response. Instead, people were led to give other responses such as that distances were too long for cycling, that hills made cycling difficult or that it was difficult to carry things on a bike. Some respondents specified "other" and then wrote this themselves but it is very likely that this most important reason for not cycling was under-reported due to the design of this question.

The study goes some way to address this by including the following passage, but because it's not an answer to a question it doesn't appear in the hastily written summaries which have appeared on websites elsewhere: "Throughout open-ended responses, e-bike users often expressed insufficient bicycle infrastructure as a significant barrier to riding more (for both standard bicycles and e-bikes), as one participant states, “I don't always have safe infrastructure to get where I need to go. [If that is the case] Then I drive” (anonymous respondent). Some of these barriers to riding a standard bicycle cannot be solved by switching to an e-bike;"

Odd uses for e-bikes
The survey results include many surprising statements from e-bike riders about ways in which they benefit from their bikes which are in fact ways of compensating for poor social policy, poor town planning and poor road/cycle-path infrastructure. Here are some examples:

At least one respondent uses their e-bike to address a social safety issue: “I ride through several homeless camps on my eighteen mile trip. My e-bike gives me a sense of security knowing that I will have the energy/power to get out of the area if I feel threatened or fear for my safety.” This should have been addressed through a combination of a more humane social policy which addressed the issue of homelessness combined with better town planning.

Another says that an e-bike allows overcoming a different problem due to poor town planning: “I live in the suburbs now, so the same errands are much longer distances. An e-bike makes it possible for me to continue to use a bike instead of a car.” Local errands ought to be over local distances. Dutch suburbs are designed to include facilities and encourage cycling.

Some report using their e-bikes to take longer routes than they would otherwise because by doing so the rider can experience less vehicular traffic. i.e. they're compensating for the lack of good cycling infrastructure where they live. Cycling infrastructure should always enable taking the shortest possible route in safety.

Some respondents claim that being able to ride at high speed enhances safety alongside faster vehicles, again compensating for poor infrastructure. Being able to ride as part of the motor traffic is aligned closely with the failed vehicular cycling ideas (it's a strategy for surviving a hostile environment but not a way to create mass cycling). This claim is similar to a popular claim made by drivers of cars that being able to break the speed limit results in better safety, but there is little evidence to support that. Higher speeds are almost always linked to more danger, regardless of the vehicle so I am skeptical that this would work differently for e-bikes. Note that the Dutch experience is the reverse. Pensioners have taken up 25 km/h assisted cycles in quite large numbers to allow them to continue a lifetime of everyday cycling using the extensive country-wide grid of safe cycling infrastructure which they already used on a normal bike. Despite the safety of the infrastructure design and their relatively small increase in speed to a maximum of 25 km/h, the extra speed, weight and slight unpredictability of assisted bicycles has resulted in a surprisingly large increase of injuries and fatalities to older people due to a rise in single rider collisions.

Mopeds and motorbikes
Unsurprisingly, most of the respondents report conflict with motor vehicles. This is a problem for anyone riding a two wheeler in traffic, powered or not). Motorcyclists were using the term SMIDSY (Sorry Mate I Didn't See You) to refer to the incidents in which drivers claimed not to have seen a motorcycle some years before cyclists picked it up. Let's remember that the e-bikes in this US survey are much faster than those which are legal elsewhere.

There's nothing new about making ever faster powered bicycles. People have found ways to put engines and motors onto bicycles thereby transforming them into mopeds and motorcycles for more than a century. People who required something like a bicycle but with a motor attached have been able to legally buy and use those vehicles for more than a century.

Modern e-bikes which assist up to 25 km/h are a new and special case in that their speed has purposefully been made compatible with normal cyclists going about their everyday business and in that the assistance is always relative to force on the pedals. In the Netherlands, slightly faster mopeds are much less popular than bicycles (powered or not) and are commonly considered to be a nuisance to cyclists.

What has been seen in Europe is that people who in the past might have bought a moped are now likely to consider buying speed-pedelecs with speeds up to 45 km/h (comparable with the majority of the US e-bikes) which are classified in a similar way to mopeds, requiring a number plate and a helmet on the rider. A combination of these types of bikes and straight electrically powered mopeds without are replacing mopeds with petrol engines. Because they don't have the same noxious emissions, most people see this as an improvement.

The faster "e-bikes" in the USA are not e-bikes here. That's not pejorative and it's not just an opinion. The law in the EU and this country places limits on assisted bicycles and such high powered machines can't be e-bikes. As a result most of the bikes in the US study would need to be registered and have a number place in Europe, the rider would have to wear a helmet and they cannot be ridden everywhere that a normal bicycle (or 25 km/h e-bike) can be ridden.

In the Netherlands, mopeds are used to make about 1% of journeys and their riders suffer from much the same prejudice as do riders of bicycles in countries where cyclists are the 1%. However I have nothing against speed pedelecs, mopeds or motorbikes. To me they're just other alternative means of transport, all of which leap with remarkable ease over the very low bar of being "better than a car", so while I don't choose to ride any of these things myself, I'm not opposed to them. What's more, I live in a city whose main claim to fame is hosting motorcycle races. This would not have been an attractive location to move to if I particularly disliked motorized bicycles of any type.

E-bikes, 3D printers, metal detectors, smart watches ?
The US survey was carried out in 2017. Over 80% of the respondents reporting buying their e-bike in 2015 or later. i.e. most were recent converts to e-biking. Over 95% report being very satisfied or satisfied with what is for many a new purchase.

Any survey which asks people who recently bought any gadget whether or not they like that gadget and whether or not they use it is likely to report that the people who recently bought a gadget do like it and do use it. It really doesn't matter what the gadget is.

You could run the same survey with accessories for normal bikes, parts thought to enhance performance of normal bikes (e.g. lighter wheels), or even totally different products such as 3D printers or smart watches. This does not invalidate any of those devices, which some people make good use of, and it also does not make the e-bike less valid either.

We should recognise that new owners of pretty much any product tend to be enthusiastic about their new purchase. Regardless of what kind of bike they have bought, people will always report using a new bicycle more than their old bicycle.

Because most of the respondents are new purchasers we have to expect that to some extent respondents self-reported opinions will express this aspect of human nature.

What is the effect on modal share ?
Any claim of a huge shift in how people get around based on this survey has to be grounded in the actual mode share figures. The survey was carried out in the USA and Canada. Unfortunately, both of those countries have staggeringly low cycling modal shares, amongst the lowest in the world.

Before modern e-bikes became popular, fewer than 1% of trips were made by bike in the USA and Canada. After e-bikes became popular this remained under 1%.

Despite their very high population densities resulting in short average trip lengths in comparison with Dutch cities, American cities such as Los Angeles and New York have almost unbelievably low rates of cycling. If you're interested in cycling, there is nothing that the rest of the world really can learn from those places except what not to do.

E-bikes are not a magic bullet which can transform a low cycling nation
In the USA, 40% of all trips are under 2 miles in length but 90% of those short trips are made by car. There's a huge potential win there taking only the shortest distance into account.

The USA used to lead the world in cycling. This bicycle,
produced by an American manufacturer in 1904, is the
sort of practical bicycle used by most people before cars
took over the roads. Modern Dutch town bikes are the same.
E-bikes are simply not required to enable the short journeys which make up the majority in any nation to be made by bicycle. No kind of special bike is required over these distances Even the most basic type of everyday bicycle can cover the majority of most peoples' short trips. The distances are so short that they can be covered by almost anyone at all in almost no time at all, riding any bicycle and without breaking a sweat.

But that is not what happens in North America. Why ? There's no safe space for cycling so cycling even over short distances is neither pleasant nor safe, on any bicycle.

If you can't convince the population to use a bicycle to ride a significant proportion of low single digit distances then it's not going to be possible to convince them to do so over longer distance either.

What can we make of the survey overall ?
The US / Canadian survey has little to no relevance to the rest of the world for several reasons:

  • The USA is a particularly hostile country in which to cycle and peoples' motivations for using an e-bike included social and planning issues which hopefully do not apply elsewhere.
  • The survey was not designed to be representative of either the population as a whole or even of e-bike owners. Survey respondents were largely e-bike enthusiasts who selected themselves.
  • Leading questions in the survey resulted in answers which may not accurately reflect the views even of those who took the survey.
  • Any survey of people who have just bought any new product will tend to be positive (see 90% of online reviews of anything).
  • The definition of an e-bike is so broad that most respondents are using types of motorized vehicles which are legally in a different class in other countries.
  • The claims of large shifts are confined to the self-reported actions of the self-selected few who took the survey. They are not represented in the modal share figures of the countries in which the survey was based.
In short: Surveys of this form can mislead the reader into thinking there has been a transformation in cycling which in reality does not exist. I will note again that the authors of the report are quite open about their methodology so I can't criticise them for this. But because of the points above, this report says very little, if anything at all, which can be translated to any other place and certainly nothing which will assist with increasing cycling modal shares in other nations.

So how can we encourage vastly more cycling ?

The logical way to increase cycling is to look to where there has been real success and copy what led to that success. It makes little sense to try to emulate even the boldest claims made in a country where less than 1% of journeys are made by bike when there is a far better example to look at. In cycling, one country leads the rest of the world by a large margin and the Netherlands is that country.

Forty years ago, city scale experiments were performed in Dutch cities to find out what was required to create a genuine and long lasting increase in attractiveness of cycling and therefore a genuine and long lasting increase in cycling.

After a small upwards bump due to the 70s fuel crisis, cycling
continue to grow slowly in the Netherlands due to new cycling
infrastructure being built. In the UK and other countries, a
decline which had begun with the growth of cars merely
paused and then continued again after the oil crisis
The result was really not surprising - the successful experiment consisted of building a comprehensive grid of infrastructure which connected every home to every destination in the city. This enabled everyone to cycle and resulted in an increase in cycling across all demographics. The same thing was copied across the entire country of the Netherlands and while the efforts are not uniform and nor is the result, the entire country now has a high cycling modal share compared with any other country.

All that other countries need to do is copy the successful experiment, choosing from the most successful Dutch schemes. Once people are enabled to cycle, they will be able to choose a bicycle which suits them. Some will opt for assisted bicycles, some will opt for speed pedelecs, some will choose a normal human powered bicycle. That's all good. But no-one should be forced to believe they need to choose what is effectively a motorbike in order to keep up with other motor vehicles.

A few minutes after publishing this blog post, the video below came to my attention. It shows an older person with a mobility scooter accidentally riding through the door of a bakery in the centre of Assen yesterday. Many older people who can no longer cycle use mobility scooters to get around in this city. They make use of the many cycle-paths which provide direct and safe routes to the city centre from suburban areas. This incident occurred in a nearly car free street at the edge of an area where no cars are allowed. If this person had made the same mistake in a different place with a lot of motor traffic, or in this exact location 40 years ago, then accidentally riding out into the middle of a busy junction could have been catastrophic.

I've added this video because it illustrates part of what I wrote above about vulnerable people. Once we reach an age where controls on something as simple as a mobility scooter become confusing enough that accidents like this can happen, the last thing that is required is more speed so that decisions have to be made more quickly and more frequently. While it is a mobility scooter and not a bicycle in this video, mobility scooters are amongst the many types of vehicle commonly used on Dutch cycle-paths alongside bicycles and there is a relationship between this incident and how pensioners in the Netherlands have more frequent crashes when riding electrically assisted bicycles. A safer built environment cannot prevent mistakes, but it always helps everyone to be safe even if they make a mistake.

Tuesday 19 June 2018

Road works vs the Dutch cyclist - a rural main route between village and city

Road works always risk placing cyclists at a dangerous disadvantage, which can result in people opting for another form of transport. To prevent this, cycle-routes must always be maintained, as can be seen in this video.

There are many other examples of this principle being applied in many different situations.

Thursday 7 June 2018

Groningen. Somehow the new infrastructure is never quite good enough

We've run cycling infrastructure study tours in this area for well over a decade. The tours are based in Assen where we live with (for three day tours) a day in Groningen which is just 30 km to the North. People always want to see Groningen because Groningen famously has the higher cycling modal share of any city in the world. It's certainly worth seeing, but Groningen's high modal share is largely due to demographic factors (a huge student population). The cycling infrastructure in Groningen simply is not as developed as in Assen and on the study tours we've always used Groningen to illustrate problems that this causes.

I've covered a few times in the past how things didn't quite measure up in Groningen, and this is another of those blog posts, focusing this time on two newly built pieces of infrastructure which are not what they could have been.

A street which has been redesigned
For many years, one of the least pleasant roads to cycle along in Groningen has been Gedempte Zuiderdiep, especially in an Easterly direction. This road has a very strange layout, where the central "road" section is reserved for buses only while the part which looks like a cycle-path is actually for private cars as well.
Gedempte Zuiderdiep this afternoon. The car was going very slowly behind a cyclist, but this meant everyone had to go very slowly because "none shall pass".
Good drivers on Gedempte Zuiderdiep just get in the way. They catch up with a slow cyclist who they can't easily overtake and stay behind them, but this means the entire "cycle-path" is blocked so that everyone has to travel at the speed of the slowest cyclist. That's no way to make cycling convenient and attractive. Bad drivers toot and rev their engines and make close passes which is no way to make cycling safe and attractive.

The layout also places cyclists in the door zone of parked cars. It's simply not a good layout for anyone except bus drivers, who have the only smooth asphalt that any more of transport has: a lane all to themselves which they hardly use at all.

Now you might think that this obviously not very good design might be the subject of "a street which has been redesigned", but it's not. Instead, Groningen has instead copied this design elsewhere.

The newly rebuilt streets, A-Weg and Westerhaven, have a few changes, which are for the worst.

  • This time the car parking is on the opposite side of the cycle-path which does slightly reduce the likelihood of dooring but only at the expense of drivers having to look all the way through their cars (or vans which can't be seen through) to decide when to pull out, rather than only over their shoulder.
  • The surface is again tiled, but even though it's new it's already even more bumpy than the old layout in Gedempte Zuiderdiep.
  • There is no allowance for how actual bicycles go through corners. Ninety degree turns on the spot are required.
  • Pedestrian crossings have been eliminated

This street used to have a slightly too narrow, but smooth separate cycle-path. Recent re-work puts cyclists in this lane with cars.
The Google Streetview car caught an example of a driver going along slowly but a bit too close for comfort behind a cyclist, much as in my photo above. The gap to the left of the cyclist, especially with that forgiving kerb providing more space on the left, will lead to very tempting opportunities for a less cautious driver to overtake. In this photo you cab see how as you cycle over this bumpy service you have a very good view of the wonderfully smooth asphalt over on the left, which is reserved for buses only.
The surface is so bumpy that it doesn't even look flat in this photo. Though this is nearly new, it is already much worse to cycle over than the older example in Gedempte Zuiderdiep, and much worse than the old asphalt cycle-path which used to be here. Note that drivers are provided with forgiving kerbs to get into parking spaces but cyclists are not provided with the same luxury so that they can park easily outside shops.
Look at the details: Completed around September last year and it's already falling apart.
To turn into Westerhaven from A-Weg you have to make a left turn next to this incredibly sharp and tall rectangular kerb. This reduces the effective width of the turning to about half. You then get to cross a couple of lanes of bus only asphalt before again riding on a bumpy cobbled surface.
This is how the old Westerhaven looked. The asphalt cycle-path was of its time and a bit narrow, but it never had cars in it. It was in need of resurfacing and the better course of action would have been to widen at the same time to improve this already good design. Oh, and look at that pedestrian crossing. There are none of those in the new design.
Why has Groningen done this ? Why substitute cyclist (and pedestrian) unfriendly designs for old but serviceable designs which merely needed a slight upgrade. Does this city actually want people to cycle ?

The new fietssnelweg (high-speed cycling highway) which isn't quite good enough
We have many examples of very good cycle-paths in this area, but none of them were used as inspiration for the new fietssnelweg. Instead of a smooth surface, this new route (the first 3 km of a 30 km route) has 1500 permanently built in bumps along its length, and while at the moment they're not a total disaster, these bumps will only get worse with time. When there are many hundreds of very well designed cycle-paths in this area which have continuous and smooth concrete surfaces, why did Groningen instead choose a substandard method to construct the new flagship fietssnelweg cycle-route ?

This could have been so much better if a continuous concrete cycle-path had been created instead of using these separate sections with bumps in-between. Also that traffic light and then the speed bumps ? The routing seems sub-optimal.

As well as the substandard surface, courtesy of Easypath Nederland B.V (read more about it here), the new fietssnelweg also does not have optimal routing. The route which has been chosen requires cyclists to ride between house boats and the gardens which belong to those house boats. I don't think it will surprise anyone to learn that the residents are not especially happy. Would you let your child walk out of your door to play in the garden if they had to cross a motorway to get to that garden ?

Protests against the new fietssnelweg in October last year because residents of the house boats, unsurprisingly, feared the arrival of many high speed cyclists going along a path between their door and their garden, changing the character of what was a relatively quiet cycle-path. I've ridden along here a couple of times in the past but never really felt comfortable doing so because of the proximity of peoples' homes. The council apparently didn't foresee this conflict source
The 'solution' which Groningen seems to have come up with is to build speed bumps on the fietssnelweg to slow cyclists down, on a cycle-path whose whole reason to exist is to speed cyclists up. I saw one of these speed bumps under construction today:
I cycled along this path a couple of weeks ago. Today the path was blocked while cycle-path speed bumps were being constructed. I don't think this will address residents' issues. In my opinion the fietssnelweg would be better on this side of the canal rather than over there.
Did anyone think this through ? For many years I've used the existing good quality route on the other side of the canal to ride to Groningen. The straightness of the new concrete section shown in the video does save time over the relatively twisty route on the other side of the canal, but couldn't a straight path have been built on that side instead, or cyclists redirected to the other side before they reached the point where there would be conflict with the house boat residents ?

Those speed bumps in full. Not what a fietssnelweg ought to be made of

This first part of this fietssnelweg leading into Groningen and then within the city seems to have a lot of built-in problems for a flagship project.

And what happens at night time on the fietssnelweg ? There is lighting provided on the motorway for the convenience of drivers, but on the cycle-path we're completely on our own in darkness. This is really not a good example of prioritizing bikes.

Wednesday 6 June 2018

Concrete cycle-paths. Smooth, maintenance free and generally preferable to asphalt

A lot of the cycle-paths in this area are made of concrete rather than asphalt. When I first moved here  it seemed a slightly odd choice because concrete is a more expensive material. I was surprised that we were getting the premium product while drivers on roads alongside those cycle-paths had the "cut-price" asphalt (immaculately laid, mind you).

The advantages of concrete have become more clear with time and were reinforced by a representative of a company which builds cycle-paths who I met a few days ago at the opening of a new path in Assen. The main advantage is that once laid, concrete cycle-paths generally require no maintenance for 30 years (see example below). We've only lived here for 11 years, but while the city has been diligent about fixing problems which occur on the asphalt paths, sometimes before they're really problems at all, and in some cases three times while we've lived here, none of the concrete paths have required any work at all so far as I can tell. For this reason I'm inclined to believe 30 year claim (see example below). Another advantage is that relatively little preparation of the ground underneath the cycle-path is required, making these paths less labour-intensive to install than would otherwise be the case. Obviously the ground underneath should be flat, but that can be sand and a 20 cm thick layer of concrete is then enough to spread the load and withstand damage without the same multiple layers of support as asphalt paths require.

There are concrete cycle-paths in this area dating from when we moved to this area which still look exactly as they did when we first saw them except that the bright colour has faded a bit. Others which already looked faded when we first came to live here also remain perfectly smooth and pleasant to cycle over. Even when there are trees nearby, these paths appear to be so completely immune to the problem of root damage.

Cycle-path which is at least ten years old. Next to trees. Perfect.
A brand new cycle-path in Assen, to be covered in the next blog post
A cycle-path in Assen which is around ten years old - surface is still perfect
Another older path, next to trees. Perfect surface The gap was cut into the path after it was laid in order to allow for expansion. There is difference in height and you can't feel this as you cycle over it.
Even where paths are also used by occasional motor vehicles (this one is only a golf kart, but tractors are quite common on rural paths) they're very resilient.
There are many hundreds of kilometres of paths like this in this area now and they're all delight to ride on. This one is in a rural area for recreational use, hence less width than a busy urban path. Note also the unsurfaced road alongside for motor vehicles. This is how routes in the countryside are unravelled.
Paths like this in the countryside are extremely popular with all cyclists who like to ride a bit further and faster.
Rural but a main route alongside a fairly busy road. No damage here even at the entrance coming up where motorists have to drive across the concrete cycle-path.
By comparison, even with good asphalt cycle-paths, root damage is a constant threat. This path was resurfaced less than ten years ago but already has been marked for repair. The repair happened very soon after the photo was taken and before the path became unpleasant to use, but it simply wouldn't have been necessary with concrete which is more expensive in the first place, but cheaper in the long term.
How these paths are constructed
The good concrete cycle-paths are poured on site and made in one long continuous pieces, usually 300 m in length. Where they join after each 300 m, there are a few cm of slightly soft asphalt to fill the gap and allow for a little movement. Every 3-10 metres (this seems quite variable) the concrete is cut after it has cured to allow for some movement. The surface is textured so that it provides grip for your tyres even when icy.
The concrete is 20 cm thick
Ground preparation is nothing more than making a level surface and applying a layer of soft sand. You can also see in this photo where the path was cut every few metres. Note that the zoom lens makes the distance between cuts seem far less than in reality. Note that when the cycle-path was completed the vertical sides were covered up. The second photo from the top shows the same cycle-path a few weeks after it was completed. There is now no vertical drop at the side.
This textured surface provides grip for bicycle tyres in any weather.

An alternative type of concrete cycle-path
Recently, the first stretch of a new fietssnelweg (cycling motorway) came into use between Haren and Groningen. It's a boon for commuting cyclists because it provides a decently wide path taking a very direct route along the canal which avoids traffic lights and junctions so is faster than any other route over its 3.5 km length. However, while this is a concrete path it's not built to the same quality as those illustrated above so unfortunately the new "fietssnelweg" is actually a bit unpleasant to cycle over.

Instead of using the successful method of construction shown above, where a path kilometres in length is made of one piece of concrete poured on site, the Haren-Groningen path is made of two metre long pre-fabricated sections from a company called Easypath Nederland B.V. These pre-fabricated sections are designed to interlock. It is supposed to be stable over time. But even newly laid these paths are already a huge step backwards in comparison with continuous concrete paths, and while those are stable over decades we can only expect the bumps between these separate sections to get worse with time. I rode over the path when it first opened and it was already possible to see nearly a centimetre difference in height between successive concrete sections.

This new method of constructing paths presumably has some advantage or it would not have been used. Perhaps it is cheap. Hopefully no-one would pay extra for an obviously lower quality. But why should cyclists put up with a cheap solution ? If this is good enough then why is it not also used for cars ? Groningen is spending many millions to upgrade the motorway into the city which runs in parallel with this cycle-path. Why doesn't the "city of cyclists" provide the same quality of experience for cyclists as they provide for drivers (in this case miraculously smooth asphalt) ? I have fears that this path simply won't prove to be both durable and of high quality.

We're stuck with this section now. I hope not to see any more of this low quality construction for cyclists.

In the worst case the gaps between sections have almost a centimetre difference in height
The sections are four metres wide and two metres in length. Running over the gaps every two metres means that you will notice them quite often if some of them are less than perfect. It's certainly not unpleasant at the moment, but I'm concerned that it will get worse and then anything which rattles on your bicycle will rattle annoyingly.
There are 3.5 km of this and it does make a very efficient cycle-path. In any other country in the world, a direct cycle-path like this would be seen as a miracle - especially when this new high quality route is parallel with four other very good, safe and convenient routes into Groningen from the South within a few kms, all of which we've taken with study tour particpants in the past: a very pretty and pleasant countryside route on the other side of the canal (the pleasantness of which excuses this more direct route being tainted by motorway noise - we're given a choice), another route a bit further to the right of this photo which passes the airport and a third which isn't all that far away from the motorway on the left but which has a few too many traffic lights for my liking and finally another route even further to the left which I used to take to reach my work in the SE of Groningen.
This video shows a short part of the Groningen-Haren path:

Please also see an updated video showing the entire route, including all the faults with this path.

Good paths are good. Not all concrete is the same.
Note that the good examples above are of concrete paths which are laid in one piece, are wide, have thick concrete which is resistant to damage, they're textured for grip and they do not have vertical drops at the side of the path. All of these aspects are important. Cycle-paths should not be constructed out of separate tiles between which there is always a bump or with thin surface layers which are guaranteed to crack. They should not have vertical drops at the sides, should not be too narrow for people to ride side by side. Corner radii should be generous, care should be taken to keep cyclists out of the "door zone", sight lines need to be long so that collisions can be avoided and priority at junctions must be obvious so that all parties know what they should do. Please read other cycle-path blog posts for other details of good design.

Longevity - update April 2019
When I ride to the west from Assen I often use an excellent concrete cycle-path between Huis-ter-Heide and Veenhuizen. This cycle-path existed when we first came to live here and featured in one of my videos from 2008. Just a few days ago I realised that what I had thought was a manhole cover was actually a commemorative plate:
This commemorative plate was laid when the cycle-path between Huis-ter-Heide and Veenhuizen came into use on the 13th of December 1990.

It's nearly 30 years old but this cycle-path still has an almost completely perfect surface. The white lines are new. Everything else is original. In theory, a freshly laid asphalt cycle-path can offer a slightly lower rolling resistance. But an asphalt cycle-path degrades very quickly by comparison so that for much of its life it will offer an inferior surface to cyclists.

The surface is also perfect on the section which runs between trees. No tree root damage is detectable here.
The quality of such cycle-paths is impressive. Their life-span is also impressive. While concrete has a significant environmental impact, this must be weighed against the impact of repeatedly repairing and rebuilding paths built of lesser materials. This long lasting cycle-path was of course constructed with the continuous poured concrete method as described at the top of this blog, not the sectional method which creates irregularities even from new.

Update August 2019
The Assen-Groningen fast cycle route is continuing to be developed. This video shows a new section, this time surfaced with the good quality continuously laid concrete:

A few days later with Judy on another section of the same newly laid cycle-path. This is really excellent.