Safe junctions and crossings

Tooting Broadway, one of London’s most dangerous junctions.
  • Most deaths and serious injuries on roads happen at junctions and crossings and where crossing provisions are inadequate.
  • Safe junctions and crossings are direct, quick and convenient.
  • When designing crossings, engineers must consider people walking as much as motor traffic moving.

People are at greatest risk when crossing provisions are non-existent or poor, or when they have to wait too long to cross. This prompts people to cross before a green man appears or to cross where it is unsafe.

The emphasis of good design, therefore, should be on improving the experience of people walking and cycling, for example by:

  • putting pedestrian crossings on “desire lines” (people don’t like to go out of their way to reach a crossing);
  • ensuring crossings are in a single stage so people are not left stranded in the carriageway;
  • minimising the waiting time for people walking and cycling (recent studies have shown that reducing wait times improves conditions for pedestrians significantly); and
  • giving people enough time to cross (the current walking speeds required by the DfT are too high for many people on foot)
  • changing the default on crossings (where traffic volumes are lower) to the green man which changes to allow vehicles to proceed only when they approach the crossing. This is being trialled by TfL in a number of locations and could have huge benefits for safety in the evenings and at night when traffic volumes are lower (but speeds are higher).

London Living Streets’ Good Design Principles for junctions and crossings are available here.

Walking as a performance metric

This sounds simple, but achieving this has not been easy given traffic engineers have historically focussed on keeping traffic moving, not people walking.

But there are signs that highways authorities are beginning to rethink things. TfL, which has responsibility for all London’s traffic signals, is the first highway authority in the UK to measure ‘pedestrian time saved’ alongside other performance metrics in its annual timing reviews of signal junctions and crossings.  More in its Walking Action Plan.

This has meant that the vast majority of crossings it has reviewed now run a cycle time of less than one minute. This means that if a pedestrian were to arrive when their red signal came on, they would wait 40 seconds or less to cross. 

London Living Streets volunteers recently initiated a study to examine the impact of TfL’s timing reviews. The Wait Time Reduction Programme examined what factors would improve users’ experience on crossings and improve safety. In particular it focussed on the impact of a reduction in wait times on users’ experiences. Sure enough, people told the researchers that they wanted more time and easier crossings. See that research here and shorter wait times in practice on the video.

Other innovations that improve the pedestrian experience and ultimately their safety include pedestrian countdown technology, which lets people know how long they have to cross the road.

A more expensive solution, for areas where high pedestrian volumes are experienced for short times, is Pedestrian SCOOT (Split Cycle Offset Optimisation Technique). This uses detectors to count the number of people waiting to cross in order to provide more green pedestrian signal time when it is busier. This is in place at more than 20 locations across London.

TfL are also starting to experiment with ‘Green man’ authority, a radical technique where traffic signals give a green signal for pedestrians continuously, only changing when vehicular traffic is detected. 

USEFUL MATERIAL

The impact of wait time reduction on the pedestrian user experience at signalised crossings in London, M F Grahn.

London Living Streets’ Good Design Principles for Junctions and Crossings.