Wednesday, November 30, 2011

UK Report Studies Infrastructure and Cycling Safety

Britain's Transportation Department just released a report which brings together all the existing data on cycliing infrastructure in the UK. It also says that it will take decades of sustained investment to achieve a functional urban cycle network across the country and a willingness to prioritise cycle traffic. The report also warns that piecemeal implementation of cycling infrastructure "is unlikely to be satisfactory".

Slowing down traffic, particularly at intersections, is identified as having the biggest likely impact on reducing cycling casualties with vehicle collisions, and also points out that this would also reduce casualties for all road users. Suggested methods of achieving this include physical traffic calming, redesigning urban streets in both their appearance and the way they are designed to be used by pedestrians and the wider use of 20mph speed limits.


However it is what the report has to say about other aspects of Britain's cycling infrastructure that will give food for thought to all sides in the debate on how best to provide the right environment for cycling in Britain and around the world. According to the report's authors there is little evidence for the safety benefits of cycle lanes, or advanced stop lines; and while segregated cycle lanes can offer greater safety to cyclists the points at which they connect with the road network can be so dangerous that they negate the safety benefit of segregation.
  • ASL - limited data, but limited evidence of benefit particularly associated with junctions. Notwithstanding this lack of evidence, ASLs may provide a priority for cyclists and might be applicable where there are heavy flows of right-turning cyclists.
  • Cycle lanes - There is little evidence in the UK that marked cycle lanes provide a safety benefit, although they may achieve other objectives. This lack of evident benefit may, however, represent a lack of quality and continuity in implementation. There is also extremely limited experimentation with, and no reported studies of, kerbed cycle lanes in the UK.
  • Segregated Cycle lanes – Providing segregated networks may reduce risk to cyclists in general, although evidence suggests that the points at which segregated networks intersect with highways can be relatively high-risk, sometimes of sufficient magnitude to offset any safety benefits of removing cyclists from the carriageway. However may be applicable particularly in rural settings.
Measures suggested as effective for improving safety at junctions include cycle pre-signals, continuing cycling lanes across junctions, raised cycle lanes at intersections, installing traffic signals at major roundabouts, and changing the design of roundabouts to slow traffic and to change the turning geometry to a sharper angle as on European roundabouts (thus eliminating the driver's blindspot). All of these measures have says the report had a measureable effect on improving safety for cyclists in other European countries most notably the Netherlands.

Interestingly while the report can seemingly find evidence for the safety benefits for cycle lanes in other European countries it finds little evidence for their effectiveness in Britain -  as the report notes "a lack of quality" may be a factor in that. Perhaps Britain's best know network of urban cycle lanes London's Barclays Cycle Superhighways is currently the focus of much criticism with poor implementation and the failure to heed safety advice.

The report also has interesting things to say about the design and implementation of both traffic calming measures and cycling infrastructure. While the authors say that traffic calming in general is beneficial to cyclists, they also advise road designers to be aware that features such as road narrowing and speed bumps have the potential for creating additional conflict between cyclists and other road users. Those designing infrastructure for cyclists also need to ensure that it meets cyclists needs otherwise warns the report it risks making a problem worse not better.

The report can be downloaded from here on the Department for Transport website.

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