Monday, 14 March 2011

B1049 Cottenham to Histon cycle path: a detailed analysis (part 2)

Note: The Cottenham-Histon cyclepath has now been upgraded and this post does not reflect its current state.

Part 2 - Histon boundary to the A14

[ continued from Part 1 - Cottenham to Histon boundary ]

The northern part of Histon has this shared use cycle path alongside a 40mph road. To a new or returning cyclist, this path would seem a much better option than being on the road.

In the photo's background, there is a white lorry parked across on the path. Of course nobody wants to inconvenience road traffic, but for the cyclist using this path, they have the difficulty of merging from a footpath, onto the road without priority. It is hard merging with 40mph traffic when you are only doing 10-20mph. If you were cycling on the road you would already have priority and the worry of overtaking is with the (safety protected) motor traffic.

Blocked cycle paths and lanes are very common.

Cycling requires real physical effort, and that is one reason why many people don't want to cycle. The path surface is not as smooth as the road, and has continuous dropped kerbs which act a little like speed bumps.

The result is that cycling is about 20% faster (or more efficient) on the road than the path. A headwind is bad enough, but the combination really saps speed.

It takes an average person 30-45 minutes to cycle from Cottenham to central Cambridge. That is a consistent time, unaffected by traffic queues and A14 crashes. The time and effort that journey takes can be significantly reduced by not using the cycle path.

This photo shows a very good reason for not using the shared use path.

Driveways often have obscured vision due to plants and bushes which means that car bonnets (and people) can pop out into the middle of your path.

If this cyclist had chosen to use the cycle path, they may have been involved in a nasty accident (for the cyclist).

At the junction of Cottenham Road and Glebe way there is a popular bus stop.

This brings you into close proximity with pedestrians which means you need to slow down again.

At Garden Walk, the pre-upgraded shared use cycle path comes to an end. This junction shows a classic problem with shared use paths.

If you cycle on the road, traffic at the side road or wanting to turn in has to give way and because you have priority - you simply cycle past this junction.

For the cyclist using the shared use path you lose priority and have to slow down or stop. A bigger problem is that it is not just the side road traffic you have to watch out for, in addition you have to watch for traffic turning into the side road.

Thats three different directions over a 270° range. Garden Walk is low traffic so risk is low but you still need to slow.

With the cycle path ended, you must join the 40mph road traffic.

At the extreme right of the photo you can see potholes. A cyclist can fall off if they hit those so need to go round them. That can be dangerous with traffic that overtakes too closely.

The newly put in on-road cycle lane - at its thinnest part it is 112cm wide.

Cambridge Cycle Campaign research says that recommended widths by many different bodies should be 2.0m wide for safety.

The cycle lane legitimises close passing which increases the risk of collision. Without the lanes, you got more room by overtaking vehicles.

The cones in place, artificially show how much room is left if a car was forced over by oncoming traffic.

In general, motorists do not want to cross a white line as it is a psychological barrier - if crossed, they are in a danger area where they could have a head on collision with oncoming traffic. As a result, vehicles will try to squeeze between a cyclist and any white line.

Correct positioning of the bicycle on the road can help control the room left by overtaking cars, but with this lane design that task is made more difficult as there is pressure to use the (too thin) cycle lane.

The upgrade has started and is doubling the shared use path width to 2.4m in most places. Pedestrians and cyclists will be able to pass each other much more easily.

The upgrade will encourage more cycling by young and timid cyclists which is a good thing. One unfortunate side effect will be the increased pressure for advanced and fast cyclists to use this path which will increase danger to those cyclists and pedestrians.

Nearer to the A14, Bridge Road's on-road cycle lanes have already been upgraded. The increased width is much safer in both directions.

The final part, I will mention is the A14 roundabout. To get over it, almost all cyclists use the shared use paths around the edge. The problem is the crossing of two slip roads.

The traffic on and joining the roundabout is traffic light controlled - cyclists do not have their own signal control. They will needs to cross each slip road in the gap between one traffic light going to red, and the other to green.

Most traffic does not indicate so it can be difficult to work out which vehicles will turn off the roundabout and is compounded by the speeds on this fast trunk road junction.

There are a lot of teenage students tring to get to college in this area. They probably take more risks than adults and are unable to read the road as they are not yet drivers.

Final comments

The dangers pointed out in these posts should not put you off cycling. One reason for posting them was to help point out the increased dangers so you can avoid them.

The danger from traffic is mostly perceived and your chances of being involved in an accident are very slim, especially if you get adult cycling training or read advanced cycling books like John Franklin's Cycle Craft.

The overall health benefits of cycling outweight any other risks.

All but the last photo were taken by me, and have been uploaded to the Photo Map on Cycle Streets.


  1. 2.4 m is ludicrously narrow for a bidirectional path to be used by pedestrians as well as just cyclists.

    The junction in your last photo was in place before we left Cambridge, and whether you rode on road or on the paths, conditions were already poor.

    It's crazy that this can happen with new development. There are no real excuses about space even on existing roads, but it's doubly ridiculous on new roads.

  2. I love those sites David, to me they seem quite achievable. However, I am totally flummoxed by the local councils approach to building cycle paths. It's a real mixed bag of success and failure. Lessons are learned but then cannot be made to stick.

    I am sure a lot of the problem is related to short term bugeting and funding. It means there is no time to fight the long battles that are needed to put some real infrastructure in place. We end up with a compromise instead.

    The best win recently has been the ten year campaign to make Gilbert Road safe for children travelling to school. It's not perfect, but for Cambridge, it is a bigger-than-ever step forward.

  3. Actually, campaigning in Gilbert Road went on for a lot longer than 10 years. It was part of my commuting route for a few years, and I was a part of that campaign for a while too (I'm second from left in this photo, which demonstrates quite well how there is plenty of space).

    I'm not actually very impressed with how it turned out.

    It was identified way back in 1999 that "people seemed to want more imaginative solutions to their traffic problems than just mandatory cycle lanes".

    But fast forward 12 years and what you have are merely advisory cycle lanes, slightly wider than before but still less than recommended minimum width.

    There's a street here in Assen called Groningerstraat which is almost exactly the same width as Gilbert Road, almost the same length, with the same number of traffic lights on its length, and much the same usage, including a secondary school part way along.

    What was done in Groningerstraat was very much more impressive. I've a number of blog posts showing different aspects of it. What's more, this was achieved without having to create conflict between cyclists and residents who wanted to park their cars on the road. They still have space to park there.

    Note also that the budget for Groningerstraat was almost exactly the same as that for Gilbert Road. One of the ever present mysteries is, of course, how British contractors manage to charge so much for so little.

    What's been done on Gilbert Road is just about the minimum improvement possible. It still falls below any reasonable standards. In part, I think we have to blame the way in which campaigning was done. Not nearly enough was asked for. Cycling campaigners are simply much too timid, too quick to compromise even before they've been asked to do so. As a result, it was easy for the council to do extremely little yet also appear to have done everything that campaigners wished for. The gratitude shown after the event completes the cycle. We can now forget about further improvements to what remains a less than thrilling example of infrastructure.

    Effective campaigning requires making a noise. In this case, it could have started by pointing out that Dutch children have so much better conditions for getting to their schools than British children do.

  4. Its a small world - I think I recognise that yellow helmet on the person to your right :-)

    I've read quite a number of your old postings. They really do puts things into perspective.

    Part of the problem with the few cycle path consultations I have seen is the way they are worded in favour of one of the proposals (they are not left online so I can't substantiate this). I am guilty of voting in favour of the cycle path that is being built. I remember at the time, when I was naive, that my thought process was 'no' but was thinking "does that mean I'll get no improvement". So I voted 'yes' and wrote down and talked over my observations such as the crossing of roads and loss of priority etc. I wish I had spotted the on-road Histon lanes - they are the worst part - supposed to be a dreadful 1.5 but is even worse being 1.2m at one point with a strange hatched area in the centre to bring the occasional driver closer than ever. I let my councillor know that I felt safer without them but it seems the process is for my comments to appear in a 'safety audit' for which I hold little hope.

    Your last paragraph re the children is especially thought provoking. The road that runs to Cottenham Primary School is waaay to busy with traffic on a school day. Kids on scooters just a couple of feet from 20mph cars.

  5. You're under that helmet ? Hi Jim !

    As for the bit about children, you've presumably seen the video of children going to one of our local primary schools. This is not an isolated example or an unusual day, but Dutch normalcy.

    It could be just the same in Britain, but not with the way things are going. Whether a cycle lane is 1.2, 1.5 or 1.7 m wide makes very little difference. Few people want their children using them alongside a lot of cars.

  6. Thank you for sharing the video of children cycling to school. What an absolute dream!

    PS, I am not Jim. I worked in the same place as him for the last three years and have had many an interesting discussion with him about cycling and transport in general.

  7. Hi
    D you know if there is going to be a solution to the A14 roundabout problem? I am afraid to cycle my cargo bike with my toddler into town as there is no way I can safely cross at the roundabout - and it is a pretty hefty piece of kit so while going via the guided busway and then back onto Histon Rd is safer, ultimately I just don't have the stamina!
    Oh, for a tunnel under the A14.....

  8. Hi DrBoo,

    I can certainly understand your difficulty. I have a tag-a-long and a 2xChild trailer and they do increase the effort somewhat.

    You might want to read about the update to the cycle path in general here:

    The latest plan is to put signal controlled lights to get across the slips roads that lead cars down onto the A14. These are the ones that most people have difficulty with.

    The other slips, that lead cars onto the roundabout will not have a push button but there will be a light for you synchronised to the car green phase for those on the roundabout.

    However, I do not know when that will be built.

    There is an alternative which I will do a more detailed post on. Have you tried, GB (when open again) past Orchard Park, then onto Northfield Avenue, Roxburgh Road, etc. it follows the striped blue route parallel to Histon Road:

    I wouldn't recommend it at school run time, but outside of those hours it is quiet. A little further and trickier to navigate but much more pleasant than Histon Road.