Painted cycle lanes may make roads more dangerous for bike riders

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geomannie
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Painted cycle lanes may make roads more dangerous for bike riders

Postby geomannie » 11 Apr 2019, 2:03pm

Abstract from https://www.sciencedirect.com/science/a ... 7518309990 published April 2019

Background: Understanding factors that influence the distance that drivers provide when passing cyclists is critical to reducing subjective risk and improving cycling participation. This study aimed to quantify passing distance and assess the impact of motor vehicle and road infrastructure characteristics on passing distance.

Methods: An on-road observational study was conducted in Victoria, Australia. Participants had a custom device installed on their bicycle and rode as per their usual cycling for one to two weeks. A hierarchical linear model was used to investigate the relationship between motor vehicle and infrastructure characteristics (location, presence of on-road marked bicycle lane and the presence of parked cars on the kerbside) and passing distance (defined as the lateral distance between the end of the bicycle handlebars and the passing motor vehicle).

Results: Sixty cyclists recorded 18,527 passing events over 422 trips. The median passing distance was 173 cm (Q1: 137 cm, Q3: 224 cm) and 1085 (5.9%) passing events were less than 100 cm. Relative to sedans, 4WDs had a reduced mean passing distance of 15 cm (Q1: 12 cm, Q3: 17 cm) and buses had a reduced mean passing distance of 28 cm (Q1: 16 cm, Q3: 40 cm). Relative to passing events that occurred on roads without a marked bicycle lane and without parked cars, passing events on roads with a bike lane with no parked cars had a reduced mean passing distance of 27 cm (Q1: 25 cm, Q3: 29 cm), and passing events on roads with a bike lane and parked cars had a mean lower passing distance of 40 cm (Q1: 37 cm, Q3: 43 cm).

Conclusions: One in every 17 passing events was a close (<100 cm) passing event. We identified that on-road bicycle lanes and parked cars reduced passing distance. These data can be used to inform the selection and design of cycling-related infrastructure and road use with the aim of improving safety for cyclists.

Are we really surprised by the main conclusion?
geomannie

the snail
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Re: Painted cycle lanes may make roads more dangerous for bike riders

Postby the snail » 11 Apr 2019, 2:51pm

Absolutely unsurprising conclusion, and that's before you take into account lanes that disappear without warning, shepherd you into the path of traffic or into the dooring zone. Surely the passing distances you quote are wrong though? I mean, I know 4x4s are a menace, but a mean passing distance of 15cm? :shock:

PaulaT
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Re: Painted cycle lanes may make roads more dangerous for bike riders

Postby PaulaT » 11 Apr 2019, 3:02pm

the snail wrote:Absolutely unsurprising conclusion, and that's before you take into account lanes that disappear without warning, shepherd you into the path of traffic or into the dooring zone. Surely the passing distances you quote are wrong though? I mean, I know 4x4s are a menace, but a mean passing distance of 15cm? :shock:


Reduced mean passing distance. So 4x4 drivers on average pass 15cm closer than other motorists.

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Re: Painted cycle lanes may make roads more dangerous for bike riders

Postby iandriver » 11 Apr 2019, 3:06pm

the snail wrote:Absolutely unsurprising conclusion, and that's before you take into account lanes that disappear without warning, shepherd you into the path of traffic or into the dooring zone. Surely the passing distances you quote are wrong though? I mean, I know 4x4s are a menace, but a mean passing distance of 15cm? :shock:


They seem to have quoted the reduced mean without giving the overall mean. So if mean for all vehicles was 150, the 4X4 would be 150 - 15 or something like that.

No great surprises here. I think they the tendency is to think the bike is in it's lane, my car is in it's lane, therefore there is no need to pull out and give more space. Add in drain covers and the rest, I've generally believed a lot of this paint is worse that useless for the afore mentioned reasons. Paint not equalling infrastructure will come as little surprise to most of us I think.
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gaz
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Re: Painted cycle lanes may make roads more dangerous for bike riders

Postby gaz » 11 Apr 2019, 4:46pm

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Wanlock Dod
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Re: Painted cycle lanes may make roads more dangerous for bike riders

Postby Wanlock Dod » 11 Apr 2019, 5:10pm

Indeed, as noted above, this principle has been known about for quite some years already. The current Scottish guidance (dated 2010) includes reference to the issue, although I am not actually aware of any instances where the installation of paint only cycle lanes has not ignored the guidelines.

Pete Owens
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Re: Painted cycle lanes may make roads more dangerous for bike riders

Postby Pete Owens » 11 Apr 2019, 5:48pm

If the Scottish guidelines genuinely took account of the evidence that cycle lanes make conditions worse then those guidelines would recommend the removal rather than the installation of cycle lanes.

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Re: Painted cycle lanes may make roads more dangerous for bike riders

Postby Bmblbzzz » 11 Apr 2019, 6:16pm

But is this due to the actual presence of the cycle lanes or their insufficient width? It strikes me that the same effect applies to one car overtaking another. On a single-carriageway 2-lane road (1 lane in each direction), a driver overtaking another car will go into the opposite lane. On a multilane road such as a motorway, they will stay in their current lane. As lanes on such roads are usually slightly narrower than on a single-carriageway major road, they're actually giving the overtaken vehicle slightly less space. In that case it's not normally a significant difference but it demonstrates the principle: where lanes are marked, it's assumed that something that's not in your lane may safely be overtaken. The white lines are taken to be sufficient protection. Similarly, overtaking a cyclist in a cycle lane, it's assumed that because the cyclist is in a separate lane, that's enough; actual distance is not too relevant. So if cycle lanes were wide enough, it wouldn't be a problem; but they'd probably have to be almost as wide as general traffic lanes.

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Wanlock Dod
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Re: Painted cycle lanes may make roads more dangerous for bike riders

Postby Wanlock Dod » 11 Apr 2019, 7:42pm

It is the width that is the issue, less than 2 m is indicated as not good, and less than 1.5 m (with a painted line) is advised against. Insufficient width is noted as not being an appropriate reason for marking narrow cycle lanes on a road (i.e. no cycle lane markings would be better). I suppose there is some scope for different interpretation of the guidelines, but not all that much.

It probably goes a long way towards explaining why infrastructure of this nature doesn’t seem to be especially good at increasing levels of cycling.

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Re: Painted cycle lanes may make roads more dangerous for bike riders

Postby Bmblbzzz » 11 Apr 2019, 8:14pm

I'm curious to know if there's any effect on passing distances from those lanes which are so substandard they're actually narrower than a bike's handlebars. I can't think of any examples currently but there were some in Bristol (eg Woodland Road) which were too narrow to get a bike in even with your wheels in the gutter.

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Lance Dopestrong
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Re: Painted cycle lanes may make roads more dangerous for bike riders

Postby Lance Dopestrong » 11 Apr 2019, 8:43pm

In a near y town the painted bike lane takes you neatly through the door zone for a load of car parking spaces. Nice.

I read somewhere - it may have been the CUK chipwrapper, but I don't recall - that the UK casualty rate for cyclists is lower for the road than for cycling infrastructure.
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Re: Painted cycle lanes may make roads more dangerous for bike riders

Postby drossall » 11 Apr 2019, 10:09pm

Bmblbzzz wrote:I'm curious to know if there's any effect on passing distances from those lanes which are so substandard they're actually narrower than a bike's handlebars.

I think the point is that, if there is no lane, drivers judge distance from the bike, and hopefully give decent clearance (not always, but that's a different issue.) If there's a lane, drivers aim simply to keep outside it. So, for a lane to be as safe as no lane (considering only overtaking clearance), there has to be space for the cyclist to be inside the lane by a safe passing distance (and therefore the vehicles).

Few lanes are that wide, so many/most lanes reduce clearance and therefore safety (again, considering only overtaking clearance, which in practice is not the only consideration). Narrow lanes fail miserably and can be quite dangerous, never mind the fact that they are encouraging cyclists to ride in the gutter.

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Re: Painted cycle lanes may make roads more dangerous for bike riders

Postby Bmblbzzz » 11 Apr 2019, 10:45pm

I agree with that as a general statement, but as I said, I was considering the special case (now thankfully rare, but common a decade or two ago) in which the bike it is not possible to cycle within the cycle lane. The bike is then a bit like a wide vehicle that occupies, say, one and a half lanes (obviously in many important respects it is different, but I'm thinking of the vehicle:lane width).

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Re: Painted cycle lanes may make roads more dangerous for bike riders

Postby Audax67 » 12 Apr 2019, 9:47am

When there are painted lanes I try to ride right on the line, since among other things they tend to be full of debris swept there by motor traffic. Other than that there are all the nasties usually associated with the gutter, e.g.

Image

(Actually, I think this one was just the Saverne city fathers (and mothers) expressing their opinion of cyclists.)

(BTW concerning the aforesaid city council, last year they held some kind of half-baked cultural jollification on the town square, and to make room for it they cut down all the shade trees and banished the snacks kiosk that has been there for the last 20+ years. What a bunch of [please insert rude word])
Have we got time for another cuppa?