Pete Owens wrote:
mjr wrote:Are those factors still the oft-cited ones from the debatable 30 year old Lund data that is rather hard to obtain? The headline figures draw no distinctions for cycleway types, junction layouts and so on and are used to wrap it all up into one answer which is "clear, simple and wrong."
The fact that cycle paths increase the danger at junctions has been well established for much longer than that - it is the reason why use of cycle paths was never made compulsory in this country in the '30s despite the best efforts of the motor lobby, unlike the rather more authoritarian regimes on the continent. It is not just one study. Indeed, most of the research has been conducted by believers in segregation who were surprised by the supposedly counter intuitive results. The effect is not marginal - we are talking about an order of magnitude here which is far more clear cut than most road safety interventions. And it does distinguish between junction layouts in that bi-directional tracks are identified as particularly dangerous.
It? It? Again, I think this seems to be describing primarily the Lund research, plus distinguishing track direction isn't really distinguishing junction layouts - relatively, bidirectional tracks are more dangerous and so we should prefer unidirectional in general, unlike most of what's being built in London - but that doesn't tell us anything about particular junction layouts. It falls into the oft-repeated trap of lumping crossroads in with forks and so on, then ignoring those differences, so it gives only generalities.
I've read quite a bit of research on this and it doesn't seem clear at all. In some cases, what seems clear at first glance is much less certain once you get to the bottom of it, like the notorious "11.3 times more dangerous" headline. In other cases, such as Jensen of Trafitek's work, an absolute fall seems to be presented as an increase mainly because it isn't as large a fall as predicted!
"An order of magnitude" is a cute way of saying it's still only a multiplier on a very small number (because cycling is generally safe). If done carefully, I suspect the benefits of increasing ridership and reduction of conflict from higher-top-speed vehicles behind would outweigh any reduction in safety from junctions - and in many cases, especially off quasi-motorways, the right tools to use will be things other than protected spaces.
There are undoubtedly design features that may mitigate this to a minor extent but that is tinkering at the edges of the problem and certainly quibbling about whether the path is shared with pedestrians or not makes no difference whatsoever.
And yet, no study I'm aware of has found that shared cycle/footways are as safe and as popular as dedicated cycleways.
I agree that there is inevitable conflict where carriageways and cycleways would cross at junctions, but it should be easier to manage,
The fact that the conflict is inevitable this means it is not possible to manage - it is a fundamental feature of the geometrical arrangement. If you arrange for a stream of left turning vehicles to approach a junction to the right of a stream of vehicles heading straight on then expext collisions at the junction.
Don't be silly! Traffic conflicts are managed all the time: priority markings, traffic signals, grade-separation and plenty more. At some point, a cycle in the stream will have had to join the stream and in a busy system, they will have had to overcome a conflict to get there - if we should expect collisions at any junction with conflicting movements, we'd just be moving the collision to where they join the stream, or where faster vehicles reach their back wheel.
so in a well-managed junction, the tipper truck driver would have had the truck crunching on bollards or similar, rather than a person.
This is getting silly. If you place a line of bollards across the mouth of a junction then it ceases to be a junction.
And in this case, there was a left-turning cycle and a left-turning truck: there was conflict only because the road design put them into the same lane (Edit: and I realise the rider may have made an ill-judged attempt to override our current default solution to such conflict: wait in line). It is, as you say, silly, but that's where the century of thinking that every rider should defend their own space on roads dominated by ever-larger motor vehicles has left us. It's a very silly approach indeed and I want it to change as soon as possible, looking at such junctions and how we can learn from history instead of endlessly repeating it.