Understanding Cycle Lanes

[thirdcrank]

This seems as good a place as any to park this link as the cyclist casualty is dissatisfied with the police investigation of "his" crash where he is said to have sustained serious injuries. It's some time now since it was announced that the police would scale down the investigation of crashes to be able to concentrate on those where somebody was killed or seriously injured (KSI.) Merely from reading media reports eg that linked in the OP, I've gained the impression that "seriously injured" has come to mean what was known in my day as "potentially fatal." ie It looks as though there will be a fatal so we may as well be ready for an inquest.

While looking for something else, I found this:

Investigation of fatal and serious injury road collisions

The police are the lead agency for collision investigation, and have the primary duty to investigate and establish the circumstances that have led to road deaths and life changing injuries. ....

https://www.app.college.police.uk/app-c ... ad-deaths/

[Stevek76]

A fair question, and one that could be asked of any cycle lane, particularly as they approach junctions, where they tend to become left filter lanes.

How is this problem handled in The Netherlands?

By making it not exist.

The cycle lanes would be physically separated and have clear priority and continuation over the side roads, typically via a raised table and coloured with red asphalt. There is actually a raised table at this junction but it's not particularly steep and only covers the footways. The general geometry of the junction would also be set up to keep turning speeds low. There's also a good chance that the side road in question would be filtered to through motor traffic and so the volume using it would also be lower.

[Mike Sales]

By making it not exist.

The cycle lanes would be physically separated and have clear priority and continuation over the side roads, typically via a raised table and coloured with red asphalt. There is actually a raised table at this junction but it's not particularly steep and only covers the footways. The general geometry of the junction would also be set up to keep turning speeds low. There's also a good chance that the side road in question would be filtered to through motor traffic and so the volume using it would also be lower.

But that would inconvenience drivers!
I often notice how, in this country, even small side roads are given long radius entries so that vehicles don't have to slow down as much.

[Pete Owens]

By making it not exist.

The cycle lanes would be physically separated

That does not make the problem go away it makes it much much worse.

The problem in this case is caused by the cyclist arriving on the scene from an unexpected position.
Riding on side paths cyclists are coming from directions that are more unexpected. It is exactly this sort of collision that side paths are knoiwn to excaserpate - making crashes three times more likely riding with the flow of traffic and a whopping ten times more likely when those paths are two-directional.

Knowing about the inherently dangerous nature of the concept you can do all sort of things to attempt to mitigate it -(bending it towards the carriageway, bending it away from the carriageway, merging it with the carriageway, painting it red, putting it on a speed bump, making cyclists give way, making cyclists dismount, pulacing barriers on the approach and so on). The measure that does make a significant difference is to ensure that the path is single direction with the traffic flow - reducing the increased crash risk to a factor of 3 rathar than 10.

However, the only way to make the problem not exist is to not route side paths across at-grade junctions. Given the basic geometry you have only 3 options.
1. Grade separation (suitable for high speed rural roads with few junctions)
2. Close the junction to motor traffic
3. Keep cyclists on the carriageway

[mjr]

The cycle lanes would be physically separated

That does not make the problem go away it makes it much much worse.

The problem in this case is caused by the cyclist arriving on the scene from an unexpected position.

That is a circular argument: we cannot have enough cycleways because motorists do not expect them because we do not have enough cycleways...

Riding on side paths cyclists are coming from directions that are more unexpected. It is exactly this sort of collision that side paths are knoiwn to excaserpate - making crashes three times more likely riding with the flow of traffic and a whopping ten times more likely when those paths are two-directional.

Still flogging that 1980s research dead horse, three and a bit decades later.

However, the only way to make the problem not exist is to not route side paths across at-grade junctions. Given the basic geometry you have only 3 options.
1. Grade separation (suitable for high speed rural roads with few junctions)
2. Close the junction to motor traffic
3. Keep cyclists on the carriageway

Of course, grade sep (assuming the motorists get the gradients) and closing junctions to motors are far better than any solution that has motorists crossing paths of cyclists, but keeping cyclists on the carriageway does not remove the problem. It is worse than having a decent cycleway crossing the side road! A cyclist on the carriageway must cross four conflict points when passing the side road on the left. A cyclist on a decent cycleway only need cross two, as clearly explained by this figure from the current Cycling Infrastructure Design handbook LTN 1/20: