Cycling in Melbourne Australia
Raised separators for bike lanes
Some interesting work done by SKM for VicRoads and written about on BVs website.
http://www.bv.com.au/change-the-world/41862/
It was a study of placing raised yellow separators between bike lane and left-most traffic lane and its effect on the passing distance chosen by motorists.
I'd urge people to have a read of at least the 2page SKM summary, the 60 page report if they have the time.
My observations:
- they talk a lot about the number of cars driving over the line inti bike lanes; I couldn't care less who drives in a bike lane when its empty
- lots of talk about cyclists "perceiving these as safer". There's a big difference between perception and reality. I guess the perception gets people riding, the reality stops them getting hurt.
- nothing done to address the fact that these will hold even more debris in the bike lane where it won't get pushed to the side by traffic.
- not much done to address the hazard that the raised lumps will cause when ridden over (ot into), especially when wet
- recommendations that these only be used where bike lanes are big and wide (and probably wouldn't need them anyway).
http://www.bv.com.au/change-the-world/41862/
It was a study of placing raised yellow separators between bike lane and left-most traffic lane and its effect on the passing distance chosen by motorists.
I'd urge people to have a read of at least the 2page SKM summary, the 60 page report if they have the time.
My observations:
- they talk a lot about the number of cars driving over the line inti bike lanes; I couldn't care less who drives in a bike lane when its empty
- lots of talk about cyclists "perceiving these as safer". There's a big difference between perception and reality. I guess the perception gets people riding, the reality stops them getting hurt.
- nothing done to address the fact that these will hold even more debris in the bike lane where it won't get pushed to the side by traffic.
- not much done to address the hazard that the raised lumps will cause when ridden over (ot into), especially when wet
- recommendations that these only be used where bike lanes are big and wide (and probably wouldn't need them anyway).
Replies to This Discussion
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Permalink Reply by Treadly and Me on -
From a quick look (exec summary and a flip through the charts), a few observations:
The separator increased the average distance of motor vehicles from the kerb by around 20 mm.
That's 2cm=bugger all at 50-60km/h. And we're going to use 35cm of bike lane space to accommodate this divider for an average 2cm extra clearance? Doesn't seem like a good trade-off to me.
It seems that the consultants didn't think the tram style dividers were the best option for bike lanes:
Other types of vertical separator may be preferable to the treatment used in the trial. See Figure 19 for a close-up view of the separator used in this trial. It is recommended that further research be undertaken to evaluate alternative cross sections that do not have the short vertical face and are narrower.
The tramline separators have a 10mm high vertical lip and a smooth edge, both of which could cause a sudden, unexpected change of wheel direction if struck unexpectedly. You can guess which way the unbalanced cyclist will fall…
Their recommendation to test a sinusoidal bump matches my view that such a separator would be both effective and much safer—if lane separators are required at all. And I note that SKM put a number of restrictions on where this sort of treatment should be used, making it not widely applicable.
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Permalink Reply by Adrian Tritschler on -
Agreed, but what worries me is that in practice the "number of restrictions" may end up being forgotten about while the barriers get put in place because to be seen to be doing something is *good* regardless of whether it is good or not.
Manufacturing limitations may well end up making any "smooth" divider still have lumps that can catch a tyre, regardless, these things are damn slippery when wet or oily regardless of what shape they are.
Unfortunately, BV and VicRoads both seem to obsess about infrastructure
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Permalink Reply by Treadly and Me on
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Yeah, as I've been known to say before, getting some infrastructure work done is an easy thing for BV to point at and say "look what we're doing for you!" Whether it's really the most effective thing that could be done is another matter.
By its very nature, invisible infrastructure is, well, invisible (at least when it comes to keeping score of "bike-specific" stuff):
‘Invisible infrastructure’ is a term created to describe all those sustainable transport policies, practices and physical measures which contribute to a cyclefriendly environment but which are not cycle-specific in their execution. It is suggested that if all of these elements were to be introduced successfully it is in theory possible for a highway authority to achieve all of its cycling objectives without the need for cycle-specific measures, i.e. visible infrastructure, other than signing and trip-end facilities.
In other words, invisible infrastructure ain't going to win a body like BV any popularity contests.
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Permalink Reply by Cory on -
Pg 34 has this.
"5.2 Cycling across the trial separator
The separator cross-section has the geometry shown in Figure 19. Cyclist trials indicated that
crossing the separator at relatively acute angles (down to around 10º) was straightforward and
posed no significant risks or difficulties to the cyclist (movement 4). This is reassuring given the
need to make this manoeuvre to avoid cars or objects that may block the lane from time to time.
The cyclists, many of whom only very rarely ride a bicycle, had little problem mounting the
separator and either crossing or returning to the bicycle lane (movement 3). Concern was raised
over the ability to safely manoeuvre the bicycle over the separator from a narrow lane width; with
cyclists balancing the need to stay out of the gutter (and preferably the rough section of the lane)
and approach the separator at as wide an angle as possible. A cyclist interviewed at Burnley Street
did not realise that the separators were mountable. "
My knee-jerk was to dismiss it. However, now I'm not so sure. On high-traffic, 80km/h arterials, they may serve a purpose... especially near intersections? It raises the cost of more lanes significantly. For the CBD and roads which accommodate it, my preference is 'shared lanes' or 'Bike boulevards'.
I'm always torn by this - the perception of what's required, to get ppl onto a bike, is sometimes different to what is actually needed.
Still - education about sharing the road should be VicRoads and BV's first priority - no matter what. (I agree, they obsess about infrastructure).
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Permalink Reply by Doddsy on -
"Still - education about sharing the road should be VicRoads and BV's first priority - no matter what. (I agree, they obsess about infrastructure)."
Check that.... Education is what is we need. Enough of this anti speeding, look left look right look bike garbage. We need to actually be telling people how to drive and how to position there cars on the road. People need to be reminded of the driving basics (eg. Don't drive in the gutter.)
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Permalink Reply by AlexZ on -
Only skimmed the doco briefly, but initial thoughts: ONLY on wide lanes.
On narrow lanes::
1/. Entirely removes the ability to ride the 10cm or so width of divider. Many narrow lanes are precisely the width of an open car door, and I refuse to ride within the lane, instead often riding the strip to ensure I don't get doored. If such a divider is placed, I would be forced to ride on the road side of the strip on these narrow paths. Riding inside the strip, swerving an opening door would not be fun onto such a strip.
2/. What are they like in the wet. Probably slippery? So cutting across them to enter or exit lane would probably require tram track-like angles of attack, not viable from a narrow lane...
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