| Topic: | Re:Re:Re:Re:Re:Re:Re:Increased casualties at Chiswick Lane | |
| Posted by: | Tom Pike | |
| Date/Time: | 27/11/24 11:27:00 |
| "most data on traffic movements involves a degree of estimate so you can't simply dismiss that which isn't telling the story you want it to." Francis, in this case we now have continuous camera counts along the High Road and King St, so it's very odd you choose to base you opinion on estimates made on a signal day's count in 2018! I'm not dismissing anything, it's you who are ignoring the most relevant data. Ironically, the Hammersmith Society previously lauded stopping up roads at the A4, saying the resulting "LTN" (their words!) allows an uninterrupted cycle route along the A4. Who would have thought that the eminently sensible solution of blocking the last two roads that take disproportionate amounts of traffic between the A4 and King St would now provoke such howling! "Basically you are telling us that there is no risk in the solution to a problem that you told us wasn't going to be a problem." Your memory, both long and short-term, appears to be failing you. As it turns out, those long posts I made in 2019 were spot on. I stated that data from the Netherlands on two-way cycling routes showed an increase in risk that must be mitigated by installing raised platforms and setback at the junctions. As I said at the time, it was critical that CS9, as it was labelled then, incorporated such mitigation. I hope it is your memory that is failing, or otherwise it looks like you're arguing in bad faith. Here's my post from 6/2/2019 to jog your memory. What we've seen on the High Road and King St is completely in line with the previous research I mention, Schepers et al. (2011), "Road factors and bicycle-motor vehicle crashes at unsignalised junctions" __________________________ Stephen, The risks are independently determined - the whole point of the paper's analysis is to separate out the factors. This enables the relative risk to be separately quantified, and then combined to estimate the overall risk. The combination is simply a multiplication of the risk factors. You are misunderstanding probability if you think an increased risk cannot be mitigated by another factor to reduce the overall risk. For example, my usual route to work might cross three roads of average risk. However, if I find a new route crossing just one road but with twice the average risk, I should swap to this new route. The relative risks are quantified in the paper as follows: Two-way track: 1.75 Cycletrack 2 -5 m back from road: 0.55 Raised cycle track: 0.49 Hence a two-way, raised track 2-5m from the road has an overall risk of 1.75 x 0.55 x 0.49 = 0.47, a reduced risk compared to single-track, unraised cycle route, less than 2 m from the main road. Of course a designer should try to use one-way tracks, but if that's not possible, it's better to install raised, set-back tracks than do nothing. Schepers shows that concentrating on just one factor, as you have done, does not lead to the safest design. In fact, if you want to ignore all but one safety factor, this paper also shows you've chosen the wrong one. A raised cycle path at intersections reduces the risk by a multiple 0.49 (0.32 to 0.77) while swapping a two-way for a one-way reduces the risk by 0.57(0.33 to 0.99). You should be concentrating your efforts on ensuring that all cyclepaths are raised at the intersections, as is indeed the case for CS9. You're not wrong that a two-way path increases risk, but you are quite wrong to make it the be-all and end-all of cycle path design, as this paper clearly shows. |