Main Area and Open Discussion > Living Room

bicycling suddenly a British speciality?!

<< < (8/9) > >>

tomos:
I would even consider using such a bike here in Paraguay. Traffic can be very problematic here and a commute that lasts 20 minutes without traffic can easily take a1 to 1.5 hour with traffic.

With such a bike traffic wouldn't be any problem anymore, I would get (more) exercise than I do now
-Shades (January 10, 2018, 09:31 AM)
--- End quote ---

I commuted (by bike) for ~10 years largely in and around Dublin city centre. Traffic was particularly bad at the time -- and exhaust fumes too, so I got the best mask/filters I could get at the time. Filters though cannot filter diesel exhaust fumes (dont know if true but I've heard that the molecules are too small). I grew to hate diesel exhaust fumes with a passion, and still do to this day.

IainB:
I originally saw the "Angles mortes" video in an earlier version, some years ago. "Angles mortes", which translates (literally) to "Deadly angles", is referred to by the term "Blind spots" in English.
I thought I had already posted about this video on the DC Forum, but, on searching, I could not seem to find it.
So, here it is. It is an excellent video, taken over a year, with bike cameras mounted fore and aft. It demonstrates quite clearly the dangers of cycling in Paris, where road/driving laws and rules to protect cyclists are apparently ineffective as they seem to be routinely ignored by motorised road vehicle users. Maybe they are infeasible/unenforceable laws/rules - I don't know.

"Blind spots"


In Auckland (NZ) where I live, they are extending "bike lanes" throughout the city and alongside (but separate to) some stretches of motorway. They are implementing it with what seems to be a pretty costly set of changes to the existing roading system, which, as a ratepayer, I can't see being cost-justified. However, if it helps to reduce bike accidents/deaths, then I would think it will have been worth it.
One of the stated intentions is apparently to try to encourage the use of bicycles and correspondingly reduce car use, but only time will tell whether that eventuates.

What reminded me to post a comment about this in the first place was that I was reading today an interesting article about "a type of road junction that causes cyclists to be killed". Specifically, it is Ipley Cross - a crossroads junction in Hampshire, UK.
The post is: Collision Course: Why This Type Of Road Junction Will Keep Killing Cyclists, and I have copied it in the spoiler below (it's quite a long article).
(Copied below sans embedded hyperlinks/images.)
SpoilerCollision Course: Why This Type Of Road Junction Will Keep Killing Cyclists
by Bez
January 7, 2018

Ipley Cross is a largely unremarkable place, an open plain where two roads cross: Beaulieu Road running north-to-south and Dibden Bottom running roughly east-to-west.

Yet it is a place of notoriety. For good reason.

Two Deaths And A Lucky Escape
In August 2011 a 15 year old boy was cycling along Beaulieu Road when he was struck from his left by a driver who failed to see him and failed to give way at the junction. The boy was sent flying, but somehow escaped with only a broken collarbone.

In May 2012 a second, almost identical incident occurred. Mark Brummell was cycling along Beaulieu Road when he was struck from his left by Stephen Chard, who failed to see Brummell and failed to give way at the junction. Brummell was killed.

In December 2016 a third, almost identical incident occurred. Kieran Dix was cycling along Beaulieu Road when he was struck from his left by Viral Parekh, who failed to see Dix and failed to give way at the junction. Dix, too, was fatally injured.

Chard was charged with causing death by careless driving and pleaded guilty; Parekh was charged with causing death by dangerous driving and pleaded guilty to causing death by careless driving, but was found not guilty of the more serious offence by a jury despite having driven through the junction’s “give way” line at 37mph without slowing.

Two questions present themselves.

Firstly, why it that the same collision keeps occurring at this junction? And secondly, why is such a standard of driving considered only to be “careless” rather than “dangerous”?

As we shall see, the answers to both are closely related.

By understanding one of the most likely causes for “failure to see” collisions at this junction, not only can we answer those questions but we can offer surprisingly straightforward solutions.

The Existing Layout
Ipley crossroads has a very simple layout: two straight sections of road cross at an angle of 69 degrees, with the north-south road (Beaulieu Road) having priority.


The innocuous, yet dangerous Ipley crossroads
Sight lines are good, although the rightward view from the easterly approach is affected somewhat by a gentle slope which rises to the northeast of the junction.

So, if it’s so easy to see, why is it apparently so easy to fail to see?

Hidden In Plain View
Far and away the most plausible answer is a phenomenon known as “constant bearing, decreasing range”, or CBDR. Originally noted by sailors, it is the phenomenon whereby two vessels, or vehicles, moving at steady speeds in straight lines towards a collision will maintain the same bearing.

If you’re a dab hand with basic trigonometry, you can probably figure the principles out for yourself, but if not then of course Wikipedia has an explanation.

CBDR is required knowledge in maritime and aviation, where ships and aircraft travel significant distances with constant speed and bearing, but it is rarely taught in the context of highways, where motion is generally less constant. But it is nonetheless important where two straight routes cross: not just two roads, but also where roads and railways cross at unsignalled level crossings (a design which is rarely if ever found in the UK but which is not uncommon in parts of the US).

Sailors and pilots are taught to detect ships and planes at a constant bearing and to take avoiding action. When it comes to drivers, however, things are very different, because almost all motor vehicles have a design flaw which means not only that a CBDR condition precedes a collision, but that unless (as we shall see) the driver does one of two things, the same condition means that the driver will never even see the phenomenon occurring.

That design flaw is the front ‘A’ pillar, at the edge of the windscreen.

The Pillar Shadow
Take a look at this plan view of a Vauxhall Zafira (as driven by Viral Parekh). When the driver looks towards the horizon, the front pillar will obscure some of the view. The red ellipse represents an approximate cross section at that point, with the shaded area beyond it being obscured as a result.


The driver’s blind spot in a Vauxhall Zafira.
Once you extrapolate that obscured area, the extent of its effect is obvious. Here’s the same set of lines drawn on the Zafira, scaled up and overlaid on Ipley Cross.


A projection of the driver’s blind spot.
At the position shown, approximately 100m from the junction at Ipley Cross, the pillar obscures roughly 12m of Beaulieu road. That’s six bicycle lengths: enough to hide not just a cyclist but a small group of riders.

Of course, as the driver approaches that junction, that obscured section of road moves towards the junction with them. As does the cyclist.

Parekh’s car had a black box type device, which (contrary to his statements to police) recorded his approach to the junction at a steady speed of 37mph. At this speed it would have taken six seconds to cover the 100m to the collision, and the following image shows the approximate areas obscured by the Zafira’s pillar at six points in time representing each incremental second leading up to impact, with the red area showing the pillar shadow one second prior to impact.


The obscured section of road becomes smaller as the driver nears the intersection.
Although the obscured section of road becomes smaller as the driver approaches, it remains large enough to completely obscure a bicycle until less than a second prior to impact: too late for either party to react.

The light blue line in the following diagram represents the approximate length of a bicycle and fits comfortably within the pillar shadow at one second before impact.


The light blue line represents the cyclist.
Naturally, as per the conditions of a collision course being signalled by a constant bearing, for any speed of the approaching car there is a speed at which a cyclist will remain obscured by the front pillar almost until the point of impact. The angles of the triangles define a ratio of speeds, and with this geometry that ratio is a little over 3:1.

So, in the case of a vehicle moving at 37mph westwards along Dibden Bottom, the CBDR speed southbound along Beaulieu Road is roughly 13.5mph. A very plausible speed for a cyclist.

But such a degree of coincidence is actually not required.

Due to the width of the pillar and the extent shadow it casts, which is much larger than a bicycle until impact is inevitable, true CBDR is not even necessary: it would be perfectly possible for a cyclist to be moving at around 17.5mph and then hit the brakes two seconds prior to impact, without ever appearing in the driver’s view.

There’s a whole range of steady speeds at which someone could approach this junction from the north and remain obscured to a driver approaching at a steady speed from the east (and, likewise, also from the south and east respectively).

Crucially, for any likely speed of an approaching car, any speed in that range is a perfectly feasible speed for a cyclist.

But there’s one more thing about Ipley Cross that makes it especially dangerous.

Critical Angles
Keen triangle enthusiasts may have started thinking about this already, but there are of course three angles to consider here.

The first is the angle between the two approach paths, which is a constant value defined by the road. At Ipley Cross this is 69 degrees.

The second is the angle between the driver’s line of travel and the line from their eyes to the front pillar. This will vary depending on the vehicle and the driver, but the approximations above put the angle at around 17 degrees to the centre of the pillar.

The third is the angle between the cyclist’s line of travel and the line from their eyes to the vehicle which will hit them.

At this location, with this vehicle, it is 94 degrees.

A car which is on a collision course at Ipley Cross with a cyclist who is obscured from the driver’s view by the front pillar will approach the cyclist from behind.

Ipley Cross is constructed in such a way that not only is it possible for a careless driver to drive straight into a cyclist without seeing them until a fraction of a second before impact, but under the exact same circumstances it is also possible for that cyclist not to see the car that hits them until the same moment.

If anyone were to take a highway engineer to a wide open space and ask them to design a junction which would readily enable two road users to collide with neither of them ever seeing each other, I doubt any would be able to manage it.

Yet this is precisely what exists.

The exact numbers, of course, depend on the driver’s height and seating position, the geometry of their vehicle, and—if you wanted to apply this to other locations—the angle at which the roads meet. The 3:1 speed ratio will vary slightly according to all these factors, and it will not always be the case that the deadly vehicle will be so hard for its victim to see, but the angle between a driver’s line of travel and the line between their eyes and the pillar will always be such that it is the slower road user who is at risk of not being seen.

The point is this: given the design of almost every motor vehicle on the road, the crossing of two straight roads can make for a perfect storm when combined with typical speeds of drivers and cyclists. Ipley Cross represents possibly the most perfect of such storms.

These collisions are, therefore, inevitable—aren’t they?

Of course not.

Human Error: The Eternal Excuse
“None of us are perfect drivers,” remarked Parekh’s defence barrister, attributing the whole affair to “human error”.

The human error in this case, and the other cases, may have been for the drivers to have maintained a constant speed (as we know Parekh did) without having physically moved their head either side of the pillar to rigorously scan the area ahead and to their right.

There are two very simple solutions to the very real risk of a driver-vs-cyclist CBDR collision.

Firstly, by slowing down significantly, any vehicle approaching from the right at a constant speed will move out of the obscured area and into view at the right of the windscreen.

And secondly, significant movement of the head will bring previously obscured sections of road into view.

It’s quite plausible that these simple strategies—either of them—could have prevented two fatalities at this one junction.

One of those strategies can, however, be easily enforced.

A Simple Solution
In 2015, nearly three years after the death of Mark Brummell, a local resident sent a pencil sketch to councillor David Harrison, which he passed on to Hampshire County Council.

It was a simple plan of Ipley Cross, with one modification: the western approach now had a short kink at its meeting with Beaulieu Road, making the junction offset.


Before, and a potential after.
With this design, no longer would it be reasonably possible for any driver to simply blow through the junction. Drivers would have to come almost to a stop.

This design would, very simply, force the slowing down that eliminates the problem of CBDR.

The image above is, of course, a mock-up. The junction was never altered.

Two years after that simple sketch was handed to the authority responsible for the junction, Kieran Dix was dead.

Is This Not Dangerous?
And, lest we forget: what of the criminal proceedings against Parekh? Why is it not deemed “dangerous” to approach this junction at 37mph without slowing?

We must note that there are two parts to the definition of dangerous driving. Firstly the standard of driving must be “far below what would be expected of a competent and careful driver”, and secondly it must be “obvious to a competent and careful driver that driving in that way would be dangerous”.

People are often drawn to the term “far below”, which offers only a vague difference from “below” as used in the definition of careless driving, but generally the problematic clause is more likely the latter: it simply doesn’t matter how dangerous the driving is if it’s not obvious that it’s dangerous.

If we don’t teach people that to approach a junction at a constant speed is inherently dangerous, and if we don’t offer a basic explanation as to why, then it is surely not obvious to most people.

“Human error” may be real, but so are techniques to mitigate or eliminate its effects—and driver training is poor when it comes to equipping people with those techniques, let alone habituating them. (And let alone reviewing knowledge of those techniques every few years.)

It would appear from media reports that Parekh’s defence was simply that he did not see Dix; the implied logic being that since he saw no other vehicles he felt no compulsion to slow down. The jury’s acquittal equally implies that they agree with this logic: it was not obvious to them that failing to see another vehicle is anything other than unavoidable.

Yet, once the nature of a collision course is explained, the need to slow down becomes obvious.

The truly contemptible human error is not in a single person carelessly failing to see. It is in our failure to continually improve the training and licensing system so as to render the need to slow down obvious; it is in our incessant support of a system which cries “human error” as an excuse to do nothing, rather than as a stimulus to understand that error in order to create a solution.

Constant Bearing, Reducing Distance
So we can easily answer both of our original questions: why the same collision keeps occurring at this junction, and why driving straight through it at a steady 37mph is not deemed “dangerous” by law.

The question we still can’t answer is that of why, when clear solutions to both problems exist, no-one ever does anything about it.

We remain on the same bearing, heading for the next collision.

Copied from: » Collision Course: Why This Type Of Road Junction Will Keep Killing Cyclists - <http://singletrackworld.com/2018/01/collision-course-why-this-type-of-road-junction-will-keep-killing-cyclists/>
==============================================

What I find interesting about this is:

* (a) that the explanation offered as being "Far and away the most plausible answer..." - i.e.. as to why that is a "killer junction" - is not proven, but is an argument hypothetically based on two concepts:

* The conventional nautical navigation concept of CBDR ("Constant Bearing, Decreasing Range”);
* The concept of the "Pillar Shadow" blind spot - being the potential forward-view blind spot radiating out from the driver's side (i.e., the RHS in this case) windscreen/door-pillar.
* (b) that the only solution put forward would seem to be relatively unsatisfactory - i.e., it would seem to be potentially relatively expensive and a constipated re-arrangement of the junction, turning it into a technically inefficient (operationally costly) sort of permanent dog's-leg diversion. I'd call that "a workaround."
* (c) that there is some past research in psychological perception that could be relevant in explaining why these accidents will continue to happen at this and other junctions.
* (d) that there are already well-understood, tried-and-tested solutions that have been devised in the UK, to this and similar road-safety problems.
So, lets look at (c) and (d):
(c) that there is some past research in psychological perception that could be relevant in explaining why these accidents will continue to happen at this and other junctions.

* Some years back, I read about an intriguing piece of psychological research that had car insurers interested. The research had identified the probable cause of why accidents at T-junctions happen, where the drivers involved would write on their insurance claim forms "I just didn't see the other car/motorbike.", or "The other driver must have been driving like a bat out of hell, because he wasn't there when I looked!" - OWTTE.


* The researchers had established by experiment that the human brain seems to have an instinctively automatic, accurate and fast response to any movement within the field of view. Sensory electrodes applied to subjects' heads showed this to be the case, and furthermore showed that any movement in an otherwise stationary field of view would immediately fire up the brain in a basic survival mode response. We are, it seems, very good at detecting movement, without even thinking about it. Then the researchers wondered why this was, and why the survival responses occurred. They postulated that this was probably a primitive developed survival instinct, when, as hunter-gatherers, we would need to be constantly scanning for sign of threats - movement from potential/concealed predators in the environment (plains or forest) we were walking through. Those who spotted the movement were more likely to have survived than those who did not.


* So the researchers wondered why this unerringly accurate survival instinct did not fire up at those strange T-junction accidents where the threat was simply apparently not perceived. After some experimentation, they figured out that, at a T-junction where the top bar of the T is the main road, the driver of a car is glancing to his right and/or left, looking through the right/left side windows. At each glance, the brain takes the frame of the window as a frame of reference for the field of view through that window, and any movement in that frame relative to the frame itself is immediately sensed/observed.


* Further experimentation showed that the brain does not perceive a moving object where that object appeared to be stationary within the frame - which is pretty much exactly the condition of CBDR ("Constant Bearing, Decreasing Range”). Only that which moves within the frame is perceived by the brain (as a threat), and non-threats (the rest) are ignored. Thus explaining the "I just didn't see the other car/motorbike." statements - they are likely to be absolutely true statements.


* Thus it would probably be incorrect to say that this illustrates "driver error" or "human error", since everything in the brain is perceptually doing exactly what it should. What it probably does illustrate though is that we were not designed to drive cars, as we have inbuilt "driving blind spots" in our sensory perception that were necessitated for our survival in the natural environment. Which is why we now know that we should take extra care as we approach a junction, as we may be literally blind, unable to perceive some of the action around us in the artificial environment.

(d) that there are already well-understood, tried-and-tested solutions that have been devised in the UK, to this and similar road-safety problems.

* Some of the most interesting, forward-thinking and sometimes non-intuitive solutions were realised and deployed in the roading infrastructure redevelopment in the building of the Milton Keynes new city (UK). The MK boundary set by the planners encompassed several villages, towns (the largest being Bletchley) and large spaces of open agricultural land, portions of which were targeted for development as new "villages" and light industry zones - which latter were separated from the habitation areas. Several existing major arterial roads and railway routes passed through the designated MK city area.


* Most of the roads had artificial landscaped embankments as protection where they passed nearby habitation areas. This contained the noise, disturbance and combustion engine fumes. The main arterial "A" roads were left unimpeded, with traffic lights where necessary at congested points or near Bletchley and other existing (older) established habitation communities. Many of the minor "B" roads were implemented as a network and a means to communicate efficiently between different communities and industrial zones within the MK area. These roads rarely had a traffic lights or ordinary stop/give way lines, since the planners had elected to put a roundabout at most junctions and let the traffic flows sort themselves out. The roundabouts worked so well that eventually many of the traffic lights and ordinary junctions had their traffic lights and lines removed and little dummy roundabout put there instead. This was done experimentally at first, and then done as a matter of course because the experiment was so incredibly successful. Other cities in the UK quickly learned from this, and they too began to replace traffic lights and ordinary junctions with these mini-roundabouts. Not only did the roundabouts improve the traffic flows, but also the accident rates at those junctions tended to decline significantly, even as traffic flows (the number of vehicles during different periods of the day) increased. In large part, this could have been attributed to the elimination of the opportunity for the CBDR frame perception blind spot to manifest itself (which was not known about at that time), because all drivers had to slow to the roundabout and only needed to look right to see and give way if a vehicle was approaching from that direction.

IainB:
@Shades:
"That video is old news." That's correct. I wasn't suggesting that it was recent news. I was referring to the old comment -IainB (2016-04-26, 17:35:34)
The video says it was "Published on 24 May 2016".
I was merely being appreciative of the technology: "Pretty impressive and well-concealed technology." It looks very civilised and not like a kludgy aftermarket add-on.
That quote I linked to also included this:
...Kiwi cyclist who has an electric motor assist on his bike, and he said his Auckland commute could take up to 1½ hrs each way, by car, but only 30mins by this bike - and he arrived fresh and not in need of a shower as he would have usually done if he had cycled on pedal power alone. ...
-IainB (April 26, 2016, 05:35 PM)
--- End quote ---
What he sees as benefits are in my view a real plus, but traffic commutes put me off.
The things I don't like about traffic are traffic exhaust pollutants and noise. They can't be good for one. Especially the diesel fume particles and carbon monoxide, so I tend to avoid long commutes in traffic for that reason.
Hearing protectors of various types are easily available. I have recently been looking at facemask filters to help there, but have not come across any that I would see as necessarily being of much comprehensive use.

"Still, the idea and execution is excellent.". Absolutely, and I would like it for myself please (but not at any cost) and for most/all of the reasons/benefits that you suggest for yourself, though I would use it for my Trek SL1000 road bike - if I could - as that bike really does suit my peculiar needs and I want to keep it and not have to get another bike.

tomos:
"Blind spots"
https://www.youtube.com/watch?v=gAethD1Io_Y
-IainB (January 10, 2018, 01:24 PM)
--- End quote ---

A lot shown in that Paris video seemed to be more along the lines of 'who cares about cyclists'.

NY not as bad as Paris, but they have bike fun there too --
Casey Neistat's Bike Lanes video:

IainB:
^^ That's soo cynical, fining the cyclists. It's presumably all about the ticketing revenue targets that are set for the police officers to "achieve".
However, in the chaotic Paris and NY traffic scenes, it really would seem that bike lanes are arguably a joke, and one might well be better off not cycling.
Road traffic and bikes simply do not mix well, and (from a risk perspective) the cyclists will always come off worst - being physically vulnerable, and not paying any road tax for any special services.

Navigation

[0] Message Index

[#] Next page

[*] Previous page