There is a noticeable increase in the number of people cycling in Birmingham, and of course most of them opt for routes that don't involve mixing with motor vehicles. The canals make for a pleasant environment, and the resurfacing of the tow paths carried out using Cycling Ambition Grant money is an improvement over the previous mud bath, but the tow paths are too narrow for use as heavily used shared-use paths. Unfortunately we're stuck with them as they are, and worse still Birmingham City Council is building new shared-use paths that are too narrow. So for the foreseeable future people taking the sustainable option for getting about will have to very much work together if we are to avoid conflict.
When there are few people on a narrow path, it really doesn't matter on which side you walk, run, or cycle. But when the path is busy, having some people on the left, some on the right, and some in the middle just impedes progress. During the rush hour it is quite common to have one bike every thirty seconds on the Worcester and Birmingham canal tow path, so the following scenario is all too common:
If pedestrians walk or run on the right of a narrow shared-use path, then when there is oncoming traffic a cyclist on the same side cannot pass, so both cyclist and pedestrian come to a complete halt. On the other hand, If everyone keeps left, then a cyclist approaching from behind can slow to the speed of the pedestrian whilst oncoming traffic passes, keeping everyone moving. Once the oncoming traffic has passed, the cyclist can safely overtake.
It works equally well if everyone is on the right, but the tradition in the UK is to keep left. Thus the signs Birmingham City Council has erected on some shared-use paths (photo at top) ask people to keep left, and they do not differentiate between walkers, joggers, and cyclists. Whilst it is disconcerting to be a pedestrian when there is a cyclist following on behind, it is in the cyclist's own interest not to ride into you, because it will be equally painful for the cyclist. Additionally, the cyclist risks damaging their bike. There is always the option of standing to one side and letting the cyclist past if they are bothering you, and that is something many pedestrians opt to do.
Of course the reason why walkers and runners tend to stay on the right is because that is what we are all told to do when walking on the carriageway, but a narrow shared-use path is very different from the carriageway. Oncoming path users can easily see each other no matter which side of the path they are on, speeds are very much lower, and the faster path users are not isolated in a metal box.
Whilst the images show the most common scenario, it is hopefully clear that the cyclists just represent path users who are faster than the third person in the image. The same applies if the two cyclists are joggers, or the pedestrian is running. Some people can run faster than some people cycle (especially if the person on wheels is in fact propelling a wheelchair), so the cyclists could be runners and the pedestrian a slow cyclist or a wheelchair user. Whatever the combination, having everyone keep left keeps everyone moving, and makes using the path less irksome and risky.