Mount Pleasant to become pleasanter?

This article was published in 1998, in Newsletter 20.

Plans are being drawn up for changes to the junctions at both ends of Mount Pleasant – the part of the ring road between Castle Street and Madingley Road. At the top of Castle Street (known as Murkett’s Corner) our proposal to construct a central approach to the junction from Huntingdon Road, helping cyclists past left-turning traffic, has essentially been accepted for inclusion in what was originally a pedestrian crossing scheme there.

In fact the plans have been extended further still to include advanced stop lines (most without approach lanes) on other arms of the junction. So we have responded by firstly asking for approach lanes, but also to go the whole hog and provide advanced stops at every signal. In a recent reply, we got the usual ‘not enough room’ response to approach lanes, but a commitment to include an advanced stop line at the Mount Pleasant approach which will certainly help cyclists who want to go to Histon Road and Victoria Road.

Castle Row, part of a possible official route to Shire Hall
Image as described adjacent

In order to provide signalled pedestrian crossings without provoking gridlock, it will be necessary to ban turns from Castle Street to Mount Pleasant and vice versa. This will create an interesting impact on Shire Hall. For cyclists it is not too much of a problem, though. It would not be too hard to provide a cycle-bypass of that corner for left turns, and the County Council has agreed to consider this. When we looked at the area, we found that there is actually already a convenient way into Shire Hall from the Mount Pleasant area via the blocked-off Castle Row. In fact, having discovered this, I’ve been using it for my trips there recently. So we suggested signing this alternative, and again the County Council is considering it.

At the Madingley Road end (which is in fact Lady Margaret Road), traffic lights will be introduced soon, together with advanced stop lines. Apart from the accident record, it is very hard to turn right out of Lady Margaret Road during the day, so these lights should be a great help to cyclists.

However, once again we are seeing advanced stop lines proposed with no way to get to them. Half-width forward stop boxes were also proposed on some approaches here. This meant that no protection would be offered from the left-turning traffic stream out of Lady Margaret Road, for example.

Therefore we suggested ways for cyclists to be more effectively provided for at both these junctions. The County Council has responded favourably regarding the half-width stop boxes, but again not on approach lanes for cyclists.

Maintaining capacity

As always, the issue is one of road space. If two traffic lanes weren’t demanded, there would be plenty of room for approach lanes. But two or three traffic lanes are always demanded so that different directions can be moving at different times, and, in the County Council’s words, ‘maximising the amount of storage space for vehicles’. This is so that the capacity of the junction can be maintained.

While the ability to move the maximum number of vehicles through traffic lights in a given time has reduced in importance, motor vehicle capacity is still apparently the overriding criterion in the design of any junction. In this instance we were told:

replacing one of the traffic lanes would cause excessive delays at the junction. Recent counts have shown that this would mean displacing 927 vehicles (over a 12 hour period) from the outside lane, into the single approach lane. Also, there is very much an element of suppressed demand for the right turn into Madingley Road, as this manoeuvre is so difficult at present.

Does that mean that we can’t have an approach lane because the new junction might then not be catering for this suppressed demand? I hope not! The situation with approach lanes was summed up like this:

Experience has shown that in most cases, cyclists can still make their way to the front of a queue, without the help of an approach lane. Therefore, an advanced stop line will still be of some benefit.

We remain unconvinced. Nevertheless, the changes to these two junctions are good news, we think.

David Earl