Thursday, 8 August 2019

Long term review: My Pashley PDQ touring recumbent. 20 years on the Ship of Theseus.

Long term review: 20 years ago I bought a Pashley PDQ recumbent bicycle for touring. I still have it and still use it.
Pashley PDQ recumbent bicycle. Compact, simple in design, reliable. Still a good buy second hand in my opinion.
Cycling need not be an expensive activity. Good quality bicycles last a long time. If we're careful to buy decent quality machines and we maintain them with some care then we can end up with the apparent luxury of a "fleet" of several bikes suitable for different purposes without that being expensive.

Recumbent cycling
I've been cycling for nearly 50 years, and for the last half of that time I've ridden recumbent bicycles for at least some of my journeys. My interest in recumbent bikes initially came about due to an injury: At the time I rode a narrow-tyred racing type bicycle with dropped handlebars and I worked as a software engineer so I had vibration in my hands on the way to and from work and then spent my working day was behind a computer with keyboard and mouse. Over several years this resulted in a carpal tunnel injury. I initially was interested in a recumbent as a way of relieving the pressure on my wrists while allowing me to continue to cycle. My first recumbent was a home made tricycle which was comfortable and fun to ride, but it was also heavy and slow. Nevertheless, it sufficed for my 16 km round trip to work and the new bike combined with a change in how I typed it resulted in more or less full recovery from my injury. But I now wanted to keep that comfort and also gain a bit of speed.

Next I bought a used Speed Ross bike. This was more like a racing bicycle to ride, being light and fast. Unfortunately it was also a bit fragile. It was fun, but not entirely trustworthy. For touring I really needed something else. The Pashley PDQ had several attractive features: two same-sized wheels (that means fewer spares to carry), a very comfortable seat, it was particularly compact, and it could take a lot of luggage. It was never the fastest of recumbents, but it also wasn't slow. It's certainly quicker than a conventional upright bike ridden in an position un-aerodynamic enough to give such a good view of where we're going.

Anyway, my PDQ was bought at some time in mid 1999 from D-Tek in the East of England, near where we lived at the time. Mine was an ex-demo machine so I got a small discount on the then new price. I paid something like 800 pounds for the bike, which works out as 40 pounds per year so far.

Blurry photo from my old commute - rapidly catching up with
a gaggle of teenagers on the way to school
I actually don't know how many kilometres the bike has been ridden in total because it outlasted a few different cheap bike computers before I fitted a reliable bike computer. I unfortunately didn't keep a record of the distances I'd covered. The total now is probably not far off 100000 km. When we lived in the UK I used the PDQ as a daily commuting bike for several years. It was also used for holidays, weekly rides with friends, occasional Audax rides, and for touring rides such as Land's End to John O'Groats, to visit relatives (Judy's parents lived 100 miles away and if Judy had gone to visit in the week I'd ride up to meet them at the weekend).

We sold most of our bikes before emigrating so when we first came to the Netherlands but I kept this one and initially had just the PDQ and my town bike so the PDQ continued to be used for all the longer recreational rides as well as a 60 km per day commute, to collect stock and to visit people in other parts of the country. I work from home now and the bike has competition for the longer rides, so the PDQ's usage has dropped to just over 2000 km a year but for our first few years in the Netherlands it was doing a lot more than that.

The PDQ's origins go back a long way. It was originally an American design, the Counterpoint Presto, until that company went bust and the design was sold to the British company Pashley. Pashley produced it with some modifications until 2003. All PDQs are now second hand and all are a minimum of 16 years old, but unless they've been treated very harshly there is probably plenty of life in them yet.

Photos of the PDQ in action
The PDQ has accompanied me on many adventures and holidays as well as on many mundane commutes and other utilitarian rides.
My PDQ when it was nearly new on a short cycle-camping trip in Lincolnshire, UK in 2000 I used to wear a helmet back then. These days I wear a cycling cap in summer or something warmer in winter.

2006 - Old Warden aerodrome. That's a Pietenpol Air Camper in the background. What makes this an interesting aircraft is that it's one of several designs created using a car engine (in this case Ford Model A) which goes faster, and therefore achieves better efficiency, than the car which donated the engine. People often assume that flying is automatically less efficient than land bound transport but that isn't true. The problem with flying isn't that it's a particularly inefficient means of transport but, just as with driving, that it has grown in popularity so much that it now threatens our survival.
A country lane somewhere between Cambridge and London
Shap Fell
This artificial hill, the highest point in Drenthe, was built for cyclists to ride over.
Judy and I on holiday

Our bikes relax while we have refreshments
On a ferry in Friesland. Lots of bikes and unfortunately also one car.
A cold foggy day in Drenthe
Bringing home bicycle racks from one of our suppliers
A group ride in the North of Groningen.
In the past the Fietsvierdaagse included 100 km routes so I've ridden some of those with the PDQ, but unfortunately they now only organise shorter distances. I've also ridden the PDQ on the 160 km Haren-Haren "classic" ride a couple of times.
Details of the bike
I apologise in advance for the dirt on the bike when I took these close-up photos. While I make sure that the bike is in good mechanical order, polishing it just takes time out from riding.

Due to the usage that this bike has had I've worn out many tyres, chains, cassettes and chainrings. The latter are made to last by replacing the chain whenever it has "stretched". This is made easier with a chain wear checking tool.

The frame, the seat, the handlebars and the luggage rack are all original, but I've rebuilt both the front and rear wheels (twice), the brakes, bell, gear shifter, cranks, chainwheel have all been replaced as they wore out or were broken.

There have been occasional incidents as well: A truck driving into me when I was on the way to work in Cambridge was the reason for one of the rear wheel rebuilds. caused me to have to rebuild the rear wheel.

The bike came with a Sachs 3x7 hub to provide a wider range of gearing but I found the hub gear part of this wasn't reliable. After rebuilding it three times with new bearings, the axle broke and so I replaced it with this standard Shimano hub which has been perfectly reliable. For the last eleven years I've had seven gears in total, which is enough for most purposes. I measure the chain length regularly and change the chain if it is worn as this saves the cost of also replacing the cassette and front chainring. I find that the SRAM PC850 chain is a good choice for a long life while not breaking the bank. There is some evidence of damaged paint to be seen. Some rust appeared on the rear triangle ten years ago and I resprayed the back end of the bike.

The handlebars: Original Tektro brake levers, which still work perfectly, reliable Sigma computer, the Busch und Muller mirror which I attached after two weeks of ownership still works perfectly - swapped from right to left after emigration. Replacement gear shifter and grips.

The original Tektro brakes were awful. They seemed impossible to adjust so that they worked reliably over any period of time. After a couple of years  I replaced them with a set of Shimano V-brakes which have been perfect. The brake blocks have of course been changed several times. Also the rims when they wore through due to braking.

The original seat rails broke after a few months. This was a production fault which Pashley were quick to set right: the faulty ones were replaced by a new design with a bit of triangulation under the rear support. 20 years later, the replacement seat rails are still fine. The seat looks worn but it's not broken and it's still a very comfortable bicycle to ride.

The bike was supplied with low quality tyres which punctured easily. I wore out a few more sets of tyres before settling on what I have now, the ever reliable and good performing Schwalbe Marathon tyres. I chose the relatively wide 47-406 size because these offer a nice smooth ride with a low rolling resistance while still fitting easily into the frame and forks. I use good quality dynamo lighting on the bike as it's always there ready for use when needed, never has a flat battery, and with this good quality headlight there is plenty of bright in a useful pattern.

When I bought the bike I wasn't at all convinced that this rubber suspension part would last. But it did. 20 years later it still works perfectly. Note that the bolt visible underneath was replaced. The originals worked loose and stripped the thread in the frame so I drilled them out, cut a thread and replaced them with a slightly larger size, installed with thread lock. Problem solved.

The idler, a skateboard wheel with grooves cut out on a lathe, was another part which I expected to fail early. However 20 years later it's still working perfectly. If it fails then I'll use a pair of standard idler wheels to replace it. The metal part around the idler can come loose and contact the chain. You can see where this has happened in the past. It's not a big issue - just tighten up the nut at the centre of the idler, taking care that washers are fitted sufficient to allow the wheel to rotate freely.

One of the most disappointing things about the PDQ as sold was the 46 tooth chainring on the front of the bike. In order to cycle at any speed it was necessary to use the step up hub gear which was less efficient. I quickly replaced the 46 tooth chainring with a 52, then a 53 and eventually settled on a larger than average 60 tooth chainring. This would be a very high gear to push if the bike had a 28" rear wheel, but with my setup it is about equivalent to a 46 tooth chainring on a bike with a larger rear wheel. Therefore I now have a sensible range of gearing without either a hub gear or a front derailleur.
It was a fine bike when I first bought it and it's still a fine bike now. Bicycles designed in a simple way, with no reliance on electrical parts or anything complex or unusual to go wrong, last a very long time. This is one of those bikes. Probably one of the best things I ever bought: it was an absolute bargain. 100000 km. 800 pounds. Just maybe I've spent twice that amount again on parts over 20 years. It still works out that this bicycle has cost me about 3 cents per km. I suspect that it costs more to walk even with cheap shoes...

Recumbent bicycles are excellent machines for touring. The PDQ has served me well, but there are also lots of other models out there which work extremely well. My wife rides a Sinner Spirit. Nazca, Optima and several other manufacturer's machines are also great. Pick one and give it a go. Second hand prices make it possible to try a bike with the likelihood that you'll lose very little if you don't like it and sell it on. A new bike also doesn't cost much if you ride it lots. Cycle touring need not be an expensive activity.

Friday, 7 June 2019

This Week in 1992. A thirty year old time capsule demonstrates both the problems due to cars and the lack of progress that we've made in addressing them.

This TV programme was transmitted in the UK in 1992. That's 27 years ago. I'm fairly sure that I watched the programme as I would certainly have been interested in this subject at that time. None of the the problems shown in this nearly 30 year old video have really been resolved. Many of the proposed solutions remain the same but they've not been implemented. It's another story of missing opportunities resulting in the problems only getting worse:

Points of interest:
  • Cambridge, like most cities, had a problem with car traffic in the city centre. They "solved" this by banning not only cars but also bicycles from some central streets. The bicycle ban was the reason why many of us who took part in protest cycle rides around that time. It was also the catalyst for the formation of the Cambridge Cycling Campaign. The bicycle ban has still not been overturned on the city centre streets so cyclists are still forced to make their journeys on less direct roads which were made more unsafe by heavier traffic due to the cars routed around the central streets.
  • When the video was made, there were already 23 million cars in the UK. A doubling was predicted to occur within 30 years. The last date for which Wikipedia has data is 2016 and by then there were 38.9 million cars on the UK's roads. i.e. up to 2016 the rate of increase was actually somewhat ahead of the prediction in the film (23*2*24/30 = 36.8).
  • Climate change effects due to cars are covered. Because the number of cars has doubled this is  twice the problem now that it was then.
  • Electric cars are suggested as a solution though the presenter points out that they could of course never solve the problem of congestion and that the emissions are mostly just pushed to power stations. We now know that total emissions of electric cars are comparable with those of IC engine cars. But even if that were not the case, adding a tiny number of them to a near doubling of the total fleet (all of which were sold as "green") they would have had no effect next to the near doubling of total emissions due to the growth in use of IC engine vehicles. This is why total emissions have also almost doubled.
  • Local pollution due to cars is seen as a problem. Many cars still ran on leaded fuel when the film was made and few had catalytic converters. These two changes to cars resulted in genuine reductions to health problems due to local exhaust emissions. However, particulate pollution always came in large part from the tyres and brakes. A doubling of the number of cars will have resulted in a doubling of this type of local pollution.
  • A traffic jam near Amsterdam. This is from a recent TV
    program about trying to solve the problem of traffic jams.
    Cars remain a huge problem in the Netherlands.
  • Amsterdam had supposedly "virtually banned" cars, with a policy of reducing car parking spaces which has echoes 27 years later as much the same thing is being done now, again to much fanfare elsewhere. I try to resist hype on the this blog. The Netherlands genuinely has taken some steps to make life without a car easier. It's possible to cycle without many interactions with cars. However much more money is spent on improving conditions for driving and very little has been done to arrest the popularity of cars. Dutch commutes are the longest on average in Europe and many people find themselves pushed into car ownership to get to work. What's more, many Dutch employers pay their employees a tax free compensation per km travelled which with an economical car can make commuting so far as possible by car profitable. As a result, Dutch car ownership has grown at a very similar rate to the UK. The Netherlands had 373 cars per thousand people in 1992 while the UK had 360 per thousand. This has now grown to 556 per 1000 in the Netherlands (2015) vs. 579 per 1000 in the UK (2016). Similar growth can be seen in all countries across the world.
  • Business owners in all countries where restrictions on cars are proposed have always worried that their customers will disappear if motor traffic is reduced. It is never actually a problem. Through traffic makes streets look busy, but drivers anxious to get to somewhere else rarely stop to browse around shops while traffic jams can make it impossible for customers to reach their shops. Motor traffic free city centre streets make for a far better shopping experience. The Dutch hotel manager who fears that Amsterdam will "become a kind of Disneyland" where "most economic activity will have disappeared" can now reflect back on years of growth in tourism in Amsterdam since that time, resulting in a problem which is quite the opposite of his prediction.
  • Luud Schimmelpennink demonstrates a velomobile in Amsterdam. Velomobiles are genuinely zero emission 365 day per year vehicles which maximise the potential of human power. They fit well both into human scale cities and make the option of cycling into a viable proposition over longer distances in all weather. Unfortunately, this genuinely innovative transport mode still receives no government support anywhere, not in the Netherlands where they remain a small minority mode even though we have more velomobiles and more manufacturers of them than any other country. Schimmelpennink is better known for other innovations such as his involvement in the famous white bicycle scheme of Amsterdam and the WitKar shared electric car system from the 1970s.
  • Professor John Whitelegg is still saying sensible things about transport.
  • Finally, the last man interviewed laments that it takes him up to two hours to drive five miles in London and he wonders why he has a car. Five miles, 7.5 km, is an ideal cycle commuting distance and even at a relaxed pace this distance can be covered in half an hour by bicycle. But sadly the majority of London remains an unpleasant place to ride a bicycle even now, so many people find themselves as reluctant drivers because for them this is the least bad option.
Progress ? What progress ?
This video shows how not addressing the problems of the present simply results in them becoming larger problems in the future. If we don't learn from the problems of the past then we will repeat them. And repeat them. And repeat them.

The problems due to cars have become larger in the last thirty years, not smaller.

While it's very nice indeed to see positive developments, it's important not to pat ourselves on the back too hard when the overall direction isn't actually what we wish it was.

More examples
See also how the same problems were seen in the UK forty and fifty years ago and in New Zealand fifty years ago, but they weren't addressed then either. The Dutch provided a video blueprint 30 years ago, which was ignored everywhere else, but of course even these policies didn't prevent greatly increased car usage in the Netherlands.

Monday, 13 May 2019

The first cycle campaigning youtube videos are in danger because of The Orchard Music and Youtube's broken copyright infringement detection

Judy and I went touring in the Netherlands in 2002 and brought
back many photos, but the even more primitive camera which
I had then couldn't record video at all.
YouTube was founded in 2005 and grew quite rapidly. At the end of 2006 it was bought out by Google and YouTube has remained under Google's ownership since that time. I started using YouTube quite early on, making what I think were the first videos of cycling infrastructure on YouTube which were created for the purpose of campaigning for better infrastructure elsewhere.

I had taken still photos and VHS video back to the UK several years before, but it was difficult to arrange to show videos to people and people couldn't see that still photos were not just of isolated spots so it was difficult to explain why what was pictured was important to a large audience. I realised that YouTube potentially offered a way of reaching that larger audience.

The four videos below were created in early to mid 2006 and are amongst a few dozen which I uploaded on the day in November 2006 when I created my YouTube account. Because the camera which I had at the time was primitive, the picture quality is poor (320x200 10 fps) and there is no sound. Much of what is shown is dated and doesn't serve as the best example but even these old cycle-paths still look like some kind of science fiction to people in many other countries where there has still not been much progress in cycling infrastructure.

This video shows the quality of a cycle-path which leads between a village and a city. See more blog posts and videos of rural cycling infrastructure.

Meerhoven was then a new housing development on the west of Eindhoven. I followed the cycling infrastructure all the way from the centre of Eindhoven, through Meerhoven, to the airport 8 km away. I made several more videos showing other parts of the guided bus system beacuse I thought was of interest at the time because Cambridge was planning a far less sophisticated guided bus which finally opened in 2011. You can see the other videos a web page about it which I created in 2006.

Cycling infrastructure in and around railway stations has long been excellent in the Netherlands. These are routes used by cyclists in Eindhoven to get to and from the railway station in 2006. Since this time I have written about many newer Dutch railway stations and in on of my recent blog posts you can see how Dutch cities continue to improve the experience for cyclists near railway stations.

When I started visiting the Netherlands, one of the first things that jumped out at me was the freedom of Dutch children. I have now written many pieces about how Dutch children cycle to school.

These old videos don't get many views these days. I'm quite happy about that because you can now find many many better videos of cycling infrastructure on my blog, e.g. at the links above under each of these videos, and on my youtube channel. But these videos are still available to watch. To me they're interesting primarily as historical artifacts. I'm fairly sure I was the first to use youtube for this purpose. Unfortunately, all my early cycling infrastructure videos are now under threat:

The Orchard Music and what appear to be fraudulent claims of copyright infringement
One of the things that changed with YouTube since 2006 is that uploaded videos are now checked for copyright infringement. This is intended to ensure that artists (or their agents) are paid for their work. It also earns money for YouTube / Google. I'm not arguing for or against this in this blog post. What I am concerned about is the overreaching claims of copyright infringement which are being made on behalf of companies which cannot be contacted and which do not reply to emails.

One of the many copyright infringement claim emails from today,
claiming that this silent video includes copyrighted music.
I regularly receive copyright infringement notices for videos which are entirely my own work, including silent videos like those above. Claims are made that the video includes copyrighted music. Obviously these silent videos don't include music, but because a claim is made against them the company involved then is allowed to run advertising on my videos in order to generate income.

In particular, an organisation called The Orchard Music makes many claims. I also received one claim from SourceAudio Holdings today. There have been other companies in the past. The Orchard Music is by far the biggest offender.

Ten incorrect claims today
How many incorrect claims do I receive ? At the time of writing this today (21:00) I have had to react to no less than ten copyright infringement claims by The Orchard Music, all of which were made against silent videos. My email inbox looks like this as a result. Almost nothing to see except notices of copyright infringement ("auteursrechtclaim ingediend") and my objections to those claims ("Je geschil is ingediend"):
My email inbox today. It consists almost entirely of "copyright infringement" claims by The Orchard Music against some of my earliest youtube videos, all of which are silent. By the time I finished writing this blog post I had received three more claims of copyright infringement just today. These claims are all against silent videos. There is no sound at all on these videos and therefore no chance at all of any of them including any content which The Orchard Music could possibly claim as their own. This is becoming ridiculous.
The problem with receiving ten copyright notices a day is that it takes a considerable amount of time to fight each one. There is no automatic way of doing this. I have to click on the link in the email and then go through several pages on clicking boxes and typing in a claim that actually I own these videos before being asked to "sign" with my name and click several more times to confirm that I know that I could be punished for making an incorrect claim. It's not only demeaning but it also takes a lot of time. Not to react would be to allow the use of my work, however old it may be, to earn money for other people. In particular, The Orchard Music. To react costs at least five minutes per complaint, more if I add in the time lost due to being distracted from whatever useful work I was doing. Merely objecting about these incorrect claims took an hour of my time yesterday. I can't continue to put so much time into trying to avoid being ripped off.

This has been going on for over a year and it has cost me hundreds of hours to deal with the  No-one at Youtube or Google or The Orchard Music reacts to my emails or tweets about this problem. I'm getting really very fed up indeed with constantly having to defend my ownership of my own work. Even if these videos are old and not particularly interesting any more, they're still mine and not theirs.

Other problems with YouTube and Google
In 2008 YouTube added an "annotations" feature. This allows text to be added to videos so that title screens and textual explanations were displayed above the video itself. It was also possible to make videos automatically pause using this feature. It worked well and I used it on many of my early videos. Unfortunately, youtube never supported annotations properly on mobile platforms and earlier this year the support also went away suddenly on the web browser as well with the result that many hundreds of hours of work that I had put into using this feature was discarded. Because youtube not only threw away this feature but also threw away the annotations themselves which I had spent many hundreds of hours to create (they provided no way of downloading the information) there is now unfortunately no way to view those early videos with annotations as they were intended to be viewed.

Google has also seemingly become unable to stop spam comments on blogpost. These days the majority of comments received are spam which tries to advertise some worthless product or other. This wastes almost as much of my time as dealing with the copyright claims on youtube.

Overall it does not seem that Google has much respect for the people who use their products. The big companies are the customers now.

Youtube: What do you want me to do ? Should I delete these old videos ? Can I trust you in future ? Should I never upload anything to your service again ? If I take your offer of "replacing" the "copyrighted music" with your cheesy non-copyright music, something which I really do not want to do, would that even stop this problem from occurring again in the future ? I have used copyright free music in the past and received copyright complaints on those videos as well !

Readers: Should I move to Vimeo ? Do readers have experience of Vimeo ? Is it better than Youtube at protecting the rights of the people who make videos ? Does it allow others to claim ownership ?

Update 6th June 2019
After a few days of silence I today received 12 emails after one another from YouTube about the disputed videos:

In all but one case, The Orchard Music decided to give up their claim to own the "music" behind my silent videos. But in once case, a private video of us riding a roller coaster many years ago, they claim they own the music that they claim exists on the silent sound track of this video. This means that The Orchard Music, who have made repeated false claims against my videos, now have my home address and content details because the only way of making an appeal is to give them this information through YouTube.

On the 8th of June the copyright claims started rolling in yet again, with The Orchard Music again trying to claim copyright infringement for the silent Crazy Mouse video. YouTube stinks.

Saturday, 30 March 2019

The Discovery Of Heaven

It was a lovely day yesterday and the cycle-paths of Drenthe were calling so I decided to make the journey to the Dwingelderveld to eat my lunch next to the somewhat famous radio telescope. Why there in particular ? I'm currently reading Harry Mulisch's "De Ontdekking van de Hemel" ("The Discovery of Heaven"). The author stayed in the area of the radio telescope during the time when he wrote the novel and the telescope features in the book as well as in the film adaption of "The Discovery of Heaven".

This was cycling for no reason other than it was pleasant to cycle so I looked at the map and roughly picked out a reasonably scenic 70 km round trip including the aforementioned planned stop for an extended lunch...

On the way out I stopped at a village bakery to buy some of their delicious, sourdough bread for my lunch.

Continuing onward, a reminder of the continuous progress being made. This country road isn't very busy, but it is used by some heavy vehicles and this cycle-path, which I followed for about 6 km before turning in a different direction, is a big improvement.

Cycle-paths which provide safe and direct routes make cycling accessible to everyone.

"For your and our safety, 60 km/h". A reminder that some places are yet to be improved.

The many cycle-paths through forests are a highlight of cycling in Drenthe

Sometimes cycle-paths through woods need bridges over areas of wet land.

The most beautiful cycle-path in the province, according to the local paper.

The destination

I made sandwiches with the bread I bought earlier and read a couple of chapters of the book.

A popular spot for hungry cyclists.

Europe's radio telescopes are linked to a centre near here, one of the many excellent things funded by the EU. The EU also contributed funds to build some of the cycle-paths along which I rode to arrive here.

On the way home, a reminder of what keeps us safe from the danger of large vehicles. It's not that Dutch drivers are especially skilled or careful, it's not that large vehicles don't exist here (for example, larger trucks are allowed here than in the UK), or that they're not allowed in to the same places as cyclists. We are safe because we rarely interact with those vehicles because both cycle-paths and the road junctions are designed to eliminate conflict and city centres exclude through traffic.

Also on the way home, the man in a fluorescent jacket is directing traffic in one direction at a time past the cherry picker. Cyclists were not hindered. Road works need not inconvenience cyclists
I returned home about three hours after I left, having had a good bit of exercise and a very tasty lunch. A very enjoyable extended lunch-break, re-discovering a little bit of heaven here on earth, using nothing more than my muscles and one of the most efficient means of transport to do so.

Monday, 25 March 2019

How bidirectional cycle-paths improve cycling safety and efficiency

Imagine if sidewalks (pavements in the UK) for pedestrians were unidirectional. If you wanted to visit your neighbour who lived on the right side of your home then you could walk there directly, but to come back home again in a legal manner you'd be expected to cross the road, walk until you were opposite your home and then cross back again. Does that make sense ? Of course not. The inconvenience of expecting people to cross the road simply to walk in the opposite direction is absurd. All sidewalks are therefore bidirectional.

Bidirectional cycle-paths, well implemented, provide cyclists with a similar level of utility as do bidirectional sidewalks. Instead of having to cross a road to travel a short distance in the "wrong" direction, cyclists can stay on the same side of a road. This makes short journeys significantly faster. It also improves their safety because they don't have to cross the road twice. Crossing the road is a significant risk: I noted in a previous blog that the most dangerous locations for cyclists in many Dutch cities are often simple uncontrolled crossings (at least where more dangerous examples of infrastructure have been eliminated)

Directness of routes is important for cycling to succeed. The more efficient that we can make cycling, the more journeys there are for which people will find it a convenient mode of transport. Bidirectional cycle-paths allow for this convenience.

It is, of course, possible to create a poor version of almost anything. That includes bidirectional cycle-paths. Where they are criticised, look for other issues. For example, poor junction design which may create conflict or make cyclists less visible to drivers.

Here are some examples of where bidirectional cycle-paths make sense. Click on the links in the descriptions of the photos to see more examples:

In a city centre
In the city centre, where a cycle-path replaced a busy road, only a bidirectional cycle-path makes sense

In the countryside

Cycle-paths through recreational areas are almost always bidirectional. There would be no sense in making them otherwise. 

Alongside a busy road
This bidirectional cycle-path is alongside a busy road through an industrial area which has four lanes of motor traffic, a central reservation and destinations on both sides. It is not desirable to require people to cross the road than is absolutely necessary. Bidirectional cycling is possible on both sides of the road.
in residential areas
This bidirectional cycle-path is in a residential suburb. In this case there is a canal on the other side of the road so it would make no sense at all to require cyclists to cross the road in order to ride next to the canal instead of next to the homes which are destinations for cyclists.
Brand new infrastructure linking a residential area to the centre of the city. There is a road behind the bushes on the right, but after the road there is nothing but the railway track. Here also it makes sense for cyclists to ride on one side of the road in both directions.

Where all destinations are on one side of the road
All destinations along this road, including shops and cafes, are on this side of road while on the other side of the road there is a canal. It would make no sense here to make cyclists cross in order to ride towards the camera. On the other side of the canal there is a bidirectional bicycle road which does not offer a through route to drivers. Note also how the road junction design reduces the danger of collision with motor vehicles. The turning radius is small and the black "cannonballs" prevent drivers from cutting the corner.
Roundabout design
One of several features which defines the safest urban roundabout design for cyclists is a design which allows safe use of bidirectional cycle-paths. These also increase convenience by allowing so few crossings to be made as possible (you are never required to ride across three arms of a roundabout to turn across traffic).

Traffic light design
Simultaneous Green traffic light junction. Cyclists can go in all directions at once when the lights are green for bikes. All motor vehicles are held behind red lights and all possibility of conflict with them is removed. A very useful design for use with bidirectional cycle-paths. Also note the width of the cycle-path, which can cope with large flows of cyclists. Also see a different traffic light design which feeds into a bidirectional cycle-path without conflict.

Through tunnels
Cycle-paths through tunnels are nearly always bidirectional. Otherwise we would require two tunnels. Tunnels are generally preferable to bridges for cyclists.

Bicycle roads
This bicycle road is on the other side of the canal from the last photo. Bicycle roads are of course always bidirectional for cyclists, though they are sometimes one-way for drivers.
Where a bicycle road ends and cycle traffic is led onto a cycle-path it would be absurd to use anything other than a bidirectional cycle-path such as is shown here. In this case there are some recreational destinations on the right of the road, but the vast majority of destinations (homes and shops) are on the left, and are served well by this cycle-path. 
Adequate width for tidal flow or at junctions between cycle-paths
Just short of four metres wide, this cycle-path copes well with considerable cycling volumes, especially tidal traffic at school times (the low building behind the cyclists to the right is a secondary school). Behind the camera there is a busy road junction.

Junctions between cycle-paths require even more width. At this point, the cycle-path exceeds six metres in width. The bridges cross a canal.
We sometimes hear blanket criticism of the idea of bidirectional cycle-paths, but it is not justified. In many cases they improve both safety and convenience for cyclists. To a first approximation a bidirectional cycle-path is always more useful than a single-direction path for the simple reason that cyclists can use it in both directions.