Where do local engineers get their designs for new cycle crossings?

This article was published in 2001, in Newsletter 35.

Problems with the modified entrance to Capital Park

When a significant amount of effort goes into redesigning a junction, and engineers have thought about cyclists, it is with some hesitation that one criticises a new layout. However, in the case of the new entrance to the Capital Park development (on the site of the old Fulbourn Hospital), there can be no doubt that the new design presents significant dangers for pedestrians and cyclists. The changes to this ‘T’ junction have included widening the side road from two to three lanes, insetting the cycle crossing two car lengths down the side road, and adding a flat-top road hump and a central reservation for cyclists and pedestrians. While I was crossing this new junction recently, I felt I was in significantly more danger than before and I began to wonder where the engineers obtained their design guidelines.

Image as described adjacent
Drivers on Cambridge Road are unable to see cyclists until the last moment

The main problems introduced by this new layout include:

  • Drivers’ poor view of cyclists using the crossing. The sharp bend in the cycle path as it approaches the crossing on both sides means that drivers on Cambridge Road are unable to see cyclists until the last moment.
  • Cyclists’ poor view of vehicles on the fast Cambridge Road. The insetting of the cycle crossing into the junction and built-up hedgerows do not allow sufficient view of traffic generally, and in particular whether it is indicating to turn into the Capital Park site. This is especially dangerous for parents with trailer bikes or trailers who must cross the junction in one go due to the extremely narrow central reservation. The main road has a 40 mph limit, but many vehicles are travelling in excess of this due to the nearby 60 mph zone.
  • Extremely narrow central reservation. Markings indicate that cyclists must stop and give way at the central reservation. However, this reservation has a tapered design that gives it a minimum width of 1.25 m. This is significantly shorter than an adult bicycle. Where did the engineers get their guidelines for this width? According to the ‘Cycling by Design’ document (see below) such reservations should be 2 m wide (absolute minimum 1.8 m).
  • Lack of dashed lines or other cycle-friendly road markings at the crossing. Most cycle crossings of this type have large dotted lines or a red surface to alert drivers to be cautious.
  • Narrow entrance and exit lanes from path. Cyclists must turn 90� as they exit or enter the path and, despite this, the path is no wider than normal. If you meet another person/cyclist coming the other way, it is extremely difficult to exit quickly if a car turns into the side road.

Image as described adjacent
Central refuge rather shorter than a bicycle. This is just 550 mm measured inside the Give Way lines

Image as described adjacent
The side road has been widened to three lanes

How can this junction be made safer?

This depends upon how busy the junction becomes when the new developments are fully open. However, considering the speed of traffic on Cambridge Road and the fact that this shared use cycle/pedestrian path forms one of the major cycling routes between Fulbourn and Netherhall School, some changes must be made:

Image as described adjacent
The shared-use path needs to be wider here, to allow for the sharp turn for the raised crossing
  • The crossing must be moved further to the mouth of the entrance. There should be no more than one car’s length in front of the crossing.
  • The cycle path should be widened at its approaches, and hedgerows or other obstacles removed to improve intervisibility. Clearly no-one involved in the installation of this crossing has tested the path since one bush has not even been pruned to the edge of the path and currently hits you in the face as you approach.
  • Dashed lines and red paint to the crossing should be added, with care taken that these are visible to drivers in low cars due to the raised level of the crossing. These measures will also encourage drivers not to enter the crossing until their exit is clear.
  • Ideally, the cycle crossing should have priority. The only way that cyclists can currently get priority to cross this junction is to use the road and I anticipate that the changes to the junction will encourage more cyclists to do so. However, one possibility is to design the junction so that drivers tend to, or are required to, give way to cyclists/pedestrians already on the crossing, as for zebra crossings.
  • A wider central reservation. Cyclists can only cross safely if the central reservation is wide enough to accommodate them. Guidelines suggest a width of 2 m (1.8 m minimum: see below)
  • Larger signs to alert drivers. Two small signs, one indicating a hump, the other of a blue cycle/pedestrian sign, are all that currently alert drivers to the dangers of persons crossing. These of course need to be positioned high.
  • Widen the path at its approach to the crossing. It seems unreasonable that the road junction has been significantly widened at the ‘T’ junction and yet the equivalent ‘T’s for cyclists have not. Are they trying to actively discriminate and force cyclists onto the road or into their cars?

Given the amount of time, effort and cost put into the modifications to this junction, the cycle-unfriendly outcome is surprising. You may wonder whether guidelines exist for different types of cycle crossings. The document Cycle-Friendly Infrastructure , a joint publication of cycle organisations and the Department of Transport, clearly emphasises that ‘intervisibility’ is an important issue in the design of any off-carriageway crossing. Another detailed document, Cycling by Design (at http://www.scotland.gov.uk, which fully endorses the UK National Cycling Strategy) describes a variety of styles of crossing including advice for engineers. The Cycling by Design document provides guidelines for visibility, widths and approach styles of cycle crossings. The type of crossing installed at the new junction to Capital Park cannot be found in either document and appears to disregard several recommendations at raised crossings. These include narrowing the mouth of the junction to less than 6 m and a central reservation width of 2 m (1.8 m minimum). Drawings of the recommended approaches to the crossing indicate that the cycle path should bend gradually to meet the road, rather than turn at the sharp angles used at the new junction.

Martyn Smith