Reducing vehicle speeds will increase cycle safetyShareThis
This week has seen the Department for Transport (DfT) publish a literature review on how the UK’s road infrastructure influences cycling casualties. The DfT asked the Transport Research Laboratory (TRL) to undertake the review that looks at how cycle accidents happen and can be reduced.
Though problematic to draw definitive conclusions from the literature, one of the main findings from the review was that cycle safety could be increased by reducing motor vehicle speeds.
This reduction of speed of vehicles could be achieved by a variety of methods, including physical traffic calming; urban design that changes the appearance and pedestrian use of a street; and, possibly, the wider use of 20 mph speed limits, according to the report.
In order to reduce the total number of cycle casualties, interventions at junctions should be a relatively high priority for planners, particularly in urban areas, where the majority of multi-vehicle collisions involving cyclists take place. Here, TRL concluded that physical calming methods at such junctions were a “reliable” means of achieving such a reduction.
This could be achieved by side entry treatments, raised cycle track crossings and signalisation of large roundabouts, for all of which there is evidence of a casualty reduction benefit for cyclists, TRL stated.
The design of roundabouts was considered by TRL. In their opinion, larger and multi-lane roundabouts were a particularly risky junction type for cyclists given the speed that motorists drive through them. Traffic lighting roundabouts is a possible solution to reducing risk for cyclists though this approach is unlikely to appeal to local authorities concerned with traffic flow.
Continuing a cycle lane, particularly if it is emphasised by a coloured surface, through a junction appears also to reduce cycle casualties, although evidence suggests that this effect is only achieved when a single lane is so marked.
Interestingly, TRL concludes that cycle advanced stop lines (ASLs) at traffic light junctions show little safety benefit, though it admits there is little research in this area.
As we know cyclist injuries involving heavy goods vehicles (HGVs) at junctions often take place at low speed and here the report suggests that Trixi mirrors (mounted below signal heads to allow drivers of heavy vehicles to see cyclists at their nearside) could be of benefit. Trixi mirrors are currently being trialled by Transport for London but wider experimentation in the UK is recommended.
A number of infrastructure interventions that are not widely used in the UK have been implemented on the continent to increase cycle safety at junctions and have had a beneficial effect on reducing cycle casualties. Particular examples include cycle lane markings continued across junctions and cycle pre-signals. Again experimentation with these approaches is recommended by the TRL.
The issue of cycle lanes represented a major area of research focus for TRL and here the TRL states there was no evidence that a segregated network that exists in the likes of the Netherlands and Denmark would work here.
It did concede that segregated networks do ultimately reduce risks to cyclists from accidents or fatalities, though TRL suggested that where segregated networks intersect with highways there was always a high-risk of accidents. This was “sometimes of sufficient magnitude” to offset any safety benefits of removing cyclists from the shared space of the road.
Introducing a segregated network of cycling lanes would involve sustained investment over decades and a willingness to prioritise cycle traffic to achieve the kind of reductions in cycle casualties that is seen as significant. Both seem unlikely.
TRL concludes that as there is a notable lack of evidence on the amount of cycling activity in the UK and the exposure of cyclists to different forms of infrastructure. This issue represented a barrier to better understanding of how to reduce risk to cyclists.
The full TRL report can be found here.
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