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But bike lanes do nothing on 30mph and 20mph roads

Painted bike lanes make no difference to the speed and closeness with which drivers pass cyclists, according to a new study, but if roads don't have centre-line markings, drivers pass cyclists more slowly.

That's the conclusion of a new study by two academics from the Universities of Leeds and the West of England. They set out to find out how much difference road markings make to the amount of space drivers give cyclists when passing, and the speed at which they pass in 20mph and 30mph zones.

Stella C. Shackel of the Institute for Transport Studies at the University of Leeds, and John Parkin, Professor of Transport Engineering at the Centre for Transport and Society, University of the West of England published their findings in the paper Influence of road markings, lane widths and driver behaviour on proximity and speed of vehicles overtaking cyclists.

Using a bike equipped with an ultrasonic distance sensor, the authors measured the passing distance of vehicles, and side-facing cameras were used to measure passing speed. Recording each pass allowed the researchers to determine the type of vehicle and so differentiate between cars, light goods vehicles, heavy goods vehicles and so on.

One of the things they were keen to determine was the effect of centre-line markings. There is already considerable research into the effect of cycle lanes, but very little into how centre lines affect driver behaviour, even though they have been in use since 1914.

A related issue the researchers identify is that standard UK traffic lanes are 3.65m wide, which puts them in what the Dutch CROW road design guidelines call the 'critical' category for combined bike and motor vehicle use. In a 'tight' lane it is not possible for an overtaking manoeuvre to be made without encroaching into the oncoming traffic lane; ‘spacious’ lanes provide for adequate passing distance without having to cross the centre-line.

"A critical cross-section provides sufficient width for drivers to overtake, but in so doing they will leave inadequate distance to the cycle user they are passing," they write.

Adequate distance means leaving enough room that the rider isn't buffeted by the vehicle's slipstream, and also that they're not scared witless by the classic 'close pass'. The researchers talk of a bike's "kinematic envelope" which they say "is wider than its physical size, and a buffer zone beyond the kinematic envelope is needed for safety reasons and to limit the feelings of danger resulting from closely passing motor traffic moving at a different speed."

One researcher then rode round a circuit near Liverpool recording driver overtakes and taking notes on a dictaphone.

After analysing the data from several hundred passes, they concluded: "Cycle lanes have no beneficial effect on passing distances and speeds. Taking these measurements as proxies for expressions of the comfort of cycling, we might then suggest that alternatives to providing space for cycle traffic are required, such as greater degrees of separation from the carriageway."

That pretty much confirms the conclusion anyone who's ever used a painted bike lane has probably already formed, but this paper should be useful ammo for cycle campaigners trying to convince planners that paint really isn't enough.

On centre-lines, they write: "If lane widths are insufficiently wide, then the removal of the centre-line would assist as this has the effect of creating slower overtaking speeds. Removal of centre-line markings would therefore be a very cost-effective way of increasing the level of comfort for cycle users."

Academic measurements are all very well, but does that work in the real world? Cambridge is currently finding out. Mill Road, a shopping street to the south-east of the city, has recently been resurfaced, but its centre-lines have not been restored.

Incidentally, if anyone wants to build their own distance sensor to prove that someone really has passed too close, University of Bath researcher Ian Walker has publishd his design on his website.

Our official grumpy Northerner, John has been riding bikes for over 30 years since discovering as an uncoordinated teen that a sport could be fun if it didn't require you to catch a ball or get in the way of a hulking prop forward.

Road touring was followed by mountain biking and a career racing in the mud that was as brief as it was unsuccessful.

Somewhere along the line came the discovery that he could string a few words together, followed by the even more remarkable discovery that people were mug enough to pay for this rather than expecting him to do an honest day's work. He's pretty certain he's worked for even more bike publications than Mat Brett.

The inevitable 30-something MAMIL transition saw him shift to skinny tyres and these days he lives in Cambridge where the lack of hills is more than made up for by the headwinds.

21 comments

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Some Fella [890 posts] 2 years ago
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Painted cycle lanes are useless?
Ive also heard of a new academic study revealing that the Pope is, in fact, Catholic.

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carytb [90 posts] 2 years ago
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Anecdotally I would tend to believe the research on the central whitelines. A lot of drivers seem to try and not cross the central lines when overtaking irrespective of the width of the road.

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KiwiMike [1239 posts] 2 years ago
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EXCELLENT.

I shall use this very paper to petition Hampshire County Council to remove the lines on my town's roads.

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John Stevenson [255 posts] 2 years ago
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Some Fella

Yep, you know that, I know that, anyone who rides bike knows that. But town planners don't know that, because they don't ride bike, so the next time they propose paint as an acceptable solution to cycle safety, we can etch this paper on granite blocks and beat them with it till they see the error of their ways.

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mrmo [2093 posts] 2 years ago
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wear a helmet and hi viz, no head phones, don't ride on pavements and don't run red lights.

lines, irrelevant......
wouldn't want to make drivers think.

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jacknorell [974 posts] 2 years ago
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Basically, our current road design is just about the worst possible then. What else is new?

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durrin [29 posts] 2 years ago
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I've noticed this many times, in fact I was thinking it while riding on a non-centrelined Swedish country road just yesterday!

But the best roads, in terms of slow car-overtaking-bike, are the ones that are only about 1,5 lanes wide (without centre lines of course). On these roads, car drivers know/feel that they need to be careful, for their _own_ safety, so they are.

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Al__S [1082 posts] 2 years ago
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Mill Road is a bit nicer- though I've still been shouted at to "move over" because I wasn't gutter hugging. White van, quarter to midnight.

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alotronic [487 posts] 2 years ago
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But painted cycle lanes give councils the feeling that they have *done something*, and surely that is important?  4

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Paul_C [481 posts] 2 years ago
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I find solid white lines to be really scary places when cycling... as the idiots behind me try to overtake without crossing them... even when I've taken primary...

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bendertherobot [1275 posts] 2 years ago
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Interesting new roads in Cardiff (Cathays Terrace being one).

They've done two things. Remove the centre lines AND put in wide cycle lanes.

The theory is that if there's a cyclist in the lane they have priority and the other traffic is sharing one lane. If there's no oncoming traffic you stay out of the cycle lane. If there is traffic oncoming then they all have to judge each other, slow down, use the lane BEHIND the cyclist, then overtake when SAFE.

Sounds odd. Seems to work.

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doubledex [32 posts] 2 years ago
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Yes, yes and yes. We have all being saying this about centre lines for years. Have you ever noticed that when the roads are being resurfaced and there is no centre line for a while, motorists are much better at overtaking? Drivers have to THINK about what they are doing. This is worthy of a serious campaign. What would also be some welcome research would be to tease out why people dont cycle and when it comes to the 'too dangerous' answer, one of the reasons to assess would be 'cars drive too close'. As a cyclist for donkeys years, this is the number one issue for me - the absolute number one.

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jollygoodvelo [1540 posts] 2 years ago
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Road paint is quite expensive stuff. Surely someone could tell councils that they could save money by not using it?

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Simmo72 [617 posts] 2 years ago
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I am at a loss as to why there is this growing trend to paint a cycle path line on the road which isn't wide enough for a large vehicle to keep out of, then introduce a new pedestrian central reservation which means the car force themselves into your space. It is utter madness. All you can do is ride further out which then winds them up even more.

And yes, no central road lines make for safer overtaking.

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elrick [4 posts] 2 years ago
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Good piece of research which confirms my experience.

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HKCambridge [222 posts] 2 years ago
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Not just Mill Road! The centre line was also removed from Gilbert road in Cambridge around 2011 when the re-engineered the road. They put in 1.7m advisory cycle lanes at the same time.

Cycle lanes may not improve passing or safety, but I would argue that they do have value as queue-busting lanes. It's not something to campaign for, but they can be handy. When East road was re-surfaced a couple of years ago a last-minute email to the council got some new advisory lanes (don't need TRO) put in since they had to repaint everything anyway. Won't encourage any new 8-year olds to cycle on the road, but does help filtering when the traffic is at a standstill, and all paid for out of the maintenance budget.

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Paul_C [481 posts] 2 years ago
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Simmo72 wrote:

I am at a loss as to why there is this growing trend to paint a cycle path line on the road which isn't wide enough for a large vehicle to keep out of, then introduce a new pedestrian central reservation which means the car force themselves into your space. It is utter madness. All you can do is ride further out which then winds them up even more.

And yes, no central road lines make for safer overtaking.

these are quite probably the most frightening places on the road for cyclists, a cyclist died here back in September:

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Housecathst [537 posts] 2 years ago
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Paul_C wrote:
Simmo72 wrote:

I am at a loss as to why there is this growing trend to paint a cycle path line on the road which isn't wide enough for a large vehicle to keep out of, then introduce a new pedestrian central reservation which means the car force themselves into your space. It is utter madness. All you can do is ride further out which then winds them up even more.

And yes, no central road lines make for safer overtaking.

these are quite probably the most frightening places on the road for cyclists, a cyclist died here back in September:

Worse that that is the pinch point without a cycle lane, where the cyclist is expect to work as the "sleeping policeman" to the motor vehicles, in the vein hope the the motorists might keep to the speed limit.

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mrmo [2093 posts] 2 years ago
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Another fine example of GCC road design, this one, you may not see it though, the cycle path actually gets narrower as you approach the refuge!

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jasecd [417 posts] 2 years ago
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@mrmo

Fortunately we all know to take the primary when approaching such sections of road. It concerns me that inexperienced cyclists may not.

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Initialised [310 posts] 2 years ago
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Simple answer, minimum width left hand lane of 5m if not possible either make it one-way or light controlled (with cyclist bypass), drop the speed limit to 20mph, physically restrict access to wide vehicles using pop-up bollards (to allow emergency service access) or remove the centre lines.