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Geometry is Killing us. Literally at one intersection.

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Geometry is Killing us. Literally at one intersection.

Old 01-12-18, 05:40 AM
  #26  
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Originally Posted by 79pmooney
I should point out that the crash in the scenario Joey is using as an example is different; it wll lead to a single vehicle crash. Cyclist will veer toward the right as he focuses all his attention to the right hoping to see that woman. This rightward veer will take him into the tree. Woman walks past unharmed.

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Old 01-12-18, 06:20 AM
  #27  
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This street view in the following article shows a yield. The Google satellite view shows a stop.

https://jalopnik.com/the-deadly-phen...-ed-1821999343

This rewording of the article makes the point more clear.

https://boingboing.net/2018/01/10/69-degrees.html

===================

It seems likely that the drivers wouldn't even be looking at the cross road in the purple and blue zones (maybe, even later). Even if there wasn't an obstruction (the A pillar), they might not be able to see a cyclist at those distances.

===================

Keep in mind that the idea is that there are three things that combined in this case to make the collisions more likely.

1- The approximate relative speeds of the to.

2- The angle (69') that would require the cyclist to look back a bit to be able to see the approaching car.

3- Where the A pillar happened to be (relative to the other things).


It appears the intersection now has a stop sign (and used to have a yield). We don't know when that change was made or what the status was when the collisions occurred.

We only know about the collisions with cyclists. We know nothing about whether there were other collisions there.

Last edited by njkayaker; 01-12-18 at 08:41 AM.
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Old 01-12-18, 07:13 AM
  #28  
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Originally Posted by njkayaker
This street view in the following article shows a yield. The Google satellite view shows a stop.
Interesting.

Google Street View, N/S Beaulieu shows stop sights, Date June 2017. Also two little bike symbols in front of the stop line.

https://www.google.com/maps/@50.8631...i6656?hl=en-US

Google Street View, E/W shows yield signs, Date May 2016. Did someone plant a sign directly in front of the yield sign? Also no bicycle symbols.
https://www.google.com/maps/@50.8631...i6656?hl=en-US

The first two accidents were in 2011 and 2012.
The third accident was in December 2016, between the two street images.

Presumably the first two accidents had the yield sign. We don't know what transpired between May 2016 and December 2016, but I presume the stop signs and bicycle symbols came after the third accident.

I don't think I've ever seen an intersection on a rural road without a stop sign, although occasionally one finds urban intersections with either yield signs, or no markings at all.

I think there may be too much temptation to hit rural yield signs at speed... and not really yield at all.

Even if one does a "rolling stop", one usually reduces speed for stops, thus no longer "constant velocity".
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Old 01-12-18, 07:43 AM
  #29  
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Originally Posted by CliffordK
Interesting.

Google Street View, N/S Beaulieu shows stop sights, Date June 2017. Also two little bike symbols in front of the stop line.

https://www.google.com/maps/@50.8631...i6656?hl=en-US
There's also a small hill and bushes in the angle that obscures visibility some.

It's also the sort of road where drivers are going to be focused straight ahead.

Originally Posted by CliffordK

Google Street View, E/W shows yield signs, Date May 2016. Did someone plant a sign directly in front of the yield sign? Also no bicycle symbols.
https://www.google.com/maps/@50.8631...i6656?hl=en-US
The sign (it's a width-limit sign) in front of the yield sign is great. That's on the opposite side from where the cars were approaching.

That sign was moved to the opposite side of the road.

=================

In both images, there are cyclists approaching from the West.

Last edited by njkayaker; 01-12-18 at 08:04 AM.
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Old 01-12-18, 08:14 AM
  #30  
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Originally Posted by JoeyBike

There is a scientific phenomenon where this occurs with a cyclist (the woman), a car (the man), and the front pillar post of the vehicle (the tree). Only instead of resulting in frustration it often ends in tragedy.
It's actually a different phenomenon. The tree case involves parallax. The pillar isn't fixed to the ground.
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Old 01-12-18, 08:21 AM
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Originally Posted by FBinNY
It's a shame that the article focused so much on the main pillar. Has it occurred to anyone here that bicycles don't have these pillars?
An interesting point is that, due to the acute angle, the car is approaching the cyclist slightly from behind.

(Anyway, in this case, there is a small hill and bushes that obscure the view.)

Originally Posted by FBinNY
The reality is that humans are not good at calculating the vectors involved and predicting the future positions of themselves and crossing objects. When the speeds and angles are right a crossing object will appear to stay in the same place (angle in the field of vision) and so it's very easy to underestimate it's speed (it's not moving at all, right?) and not be aware if the risk of collision.
All you have to note is that the bearing angle between you and the other vessel is not changing.

The entire point is the fact that the bearing angle isn't changing means collision is certain.

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Old 01-12-18, 09:15 AM
  #32  
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beautiful women have been stooping traffic for a long time & many leave us breathless
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Old 01-12-18, 12:00 PM
  #33  
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Originally Posted by njkayaker
An interesting point is that, due to the acute angle, the car is approaching the cyclist slightly from behind.

(Anyway, in this case, there is a small hill and bushes that obscure the view.)



All you have to note is that the bearing angle between you and the other vessel is not changing.

The entire point is the fact that the bearing angle isn't changing means collision is certain.
There's now a STOP sign at the intersection.

So now only people who do not slow down at all and blow through the stop sign (and their victims) will find themselves in a CBDR.

-mr. bill
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Old 01-12-18, 12:09 PM
  #34  
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Originally Posted by mr_bill
There's now a STOP sign at the intersection.
Yes, I was the one who pointed that out.

Originally Posted by mr_bill
So now only people who do not slow down at all and blow through the stop sign (and their victims) will find themselves in a CBDR.
The CBDR case is irrelevant to the older intersection with yield signs too. "Blowing through" a yield is the same mistake.

Heck, there was a hill and bushes blocking the view.

CBDR isn't that useful a concept for driving anyway.

Last edited by njkayaker; 01-12-18 at 12:22 PM.
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Old 01-12-18, 12:16 PM
  #35  
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Originally Posted by CliffordK
Oh, I can imagine the return of the bubble shaped Pacer.



Perhaps a little more work to reduce the pillars. There are quite a few cars with frameless windows on the doors, but still have the main pillars.

That is one thing I dislike about Mom's Prius, really bad rear visibility
IIRC the pillar thing is due to changes in vehicle crash resistance regulations.

it personally bugs me that most newer cars have much less visibility due to design and safety requirements than older cars. Part of the reason I am still driving a 97 bmw
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Old 01-12-18, 02:23 PM
  #36  
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Originally Posted by Ninety5rpm
Simple solution:

Heck, they wouldn't even implement the "change one road" solution... much less make a round-a-bout.



The fact is the local authorities don't give a hoot about injured or dead cyclists... any more than society at large.

To quote a comment offered by one of the readers of the site:
I agree that blind spots, CBDR, stop signs, give way signs, junction designs are part of the problem, here and at similar junctions. The real problem though is the way people who drive a vehicle and kill someone else are allowed to simply hang their head and say sorry, opps, slap my wrist, give me a fine, possibly even stop me driving for a wee while, maybe lock me up if I’ve very very naughty.
Maybe some properly scary punishments, like lifetime driving bans, jail terms similar to manslaughter?
As a society, we tend to give preferential treatment to motorists... unless drugs or alcohol are involved. This all comes from the "oops, it was an "accident" mentality. In the case of one dead victim mentioned in the OP link... there was plenty of evidence to indicate the driver never even slowed down, in spite of there being a "Give Way" zone. (cheap version of a stop sign... )

In fact the driver 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.
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Old 01-12-18, 02:28 PM
  #37  
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Thanks to Joey, for bringing this up... so other cyclists may think about it.

As a boater and boat racer, I have faced the CBRD situation quite a bit, and am quite familiar with it.
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Old 01-12-18, 02:41 PM
  #38  
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Originally Posted by genec
...

The fact is the local authorities don't give a hoot about injured or dead cyclists... any more than society at large.

To quote a comment offered by one of the readers of the site:


As a society, we tend to give preferential treatment to motorists... unless drugs or alcohol are involved. This all comes from the "oops, it was an "accident" mentality. In the case of one dead victim mentioned in the OP link... there was plenty of evidence to indicate the driver never even slowed down, in spite of there being a "Give Way" zone. (cheap version of a stop sign... )

In fact the driver 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.
If avoiding crashes is not enough motivation for them to drive more carefully, then obscure threats of remotely possible prison time are not going to make a difference (I say "remotely possible" because the odds that any one person will crash and kill someone is remotely low, therefore the having to suffer the consequences stemming from killing someone due to careless driving is only remotely possible for any one person).

Last edited by Ninety5rpm; 01-12-18 at 02:44 PM. Reason: improve wording
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Old 01-12-18, 04:08 PM
  #39  
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Originally Posted by genec
Heck, they wouldn't even implement the "change one road" solution... much less make a round-a-bout.

The fact is the local authorities don't give a hoot about injured or dead cyclists... any more than society at large.
They have, however, actually made some changes.

As mentioned above, sometime around the time of the third accident (second fatality), the yield signs were replaced with stop signs, and bike images were painted on the road.

Even if drivers roll through the stop signs, it is less likely that they'll be rolling through them at constant velocity without looking.

So, re-routing the roads may not have been necessary.

I find yield signs, and unmarked intersections rare in urban areas here in the USA. But, I don't think I've ever seen a yield sign in rural areas in the USA. And this very accident may well be the reason. Rolling stop or not, people are going faster through yield signs, and just don't pay as much attention.

Oh, perhaps there are unmarked street corners on gravel roads on forest service roads in the mountains. But even in that case, there often is a main street and a side street with pretty obvious precedence.

Hopefully the British will actually evaluate other intersections. Rather than adding costly, and potentially dangerous offset intersections, or millions of roundabouts, they should just replace all of the yield signs with stop signs. Also stop doing that silly putting a sign directly in front of a stop/yield sign (shared sign post instead?)
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Old 01-12-18, 04:58 PM
  #40  
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Originally Posted by Ninety5rpm
If avoiding crashes is not enough motivation for them to drive more carefully, then obscure threats of remotely possible prison time are not going to make a difference (I say "remotely possible" because the odds that any one person will crash and kill someone is remotely low, therefore the having to suffer the consequences stemming from killing someone due to careless driving is only remotely possible for any one person).
Perhaps you are right... This line of reasoning has been discussed here before... None the less, I would still prefer it (especially since as you say "the odds are so low...") if anyone who has managed to kill someone with their car... was never allowed to drive again.
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Old 01-12-18, 05:16 PM
  #41  
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Originally Posted by genec
Perhaps you are right... This line of reasoning has been discussed here before... None the less, I would still prefer it (especially since as you say "the odds are so low...") if anyone who has managed to kill someone with their car... was never allowed to drive again.
There's a justice consideration too. It's one thing if they were doing something blatantly wrong like DUI or texting. But if it's just the result of an honest mistake - humans are inherently fallible - we generally don't punish in our society. That's fundamental to who we are.
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Old 01-12-18, 06:06 PM
  #42  
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Originally Posted by Ninety5rpm
There's a justice consideration too. It's one thing if they were doing something blatantly wrong like DUI or texting. But if it's just the result of an honest mistake - humans are inherently fallible - we generally don't punish in our society. That's fundamental to who we are.
OK, part of that same old discussion... a damn lot of those "honest mistakes" are due to just not giving a damn and not paying attention while driving...

As you said, it doesn't happen often (only 30,000 - 40,000 deaths a year, right?)

So perhaps the threat of loss of driving privilege might just reduce the "honest mistakes" just a wee bit.

If you want to drive in Germany you need to be dedicated, which makes for better drivers. And better drivers means fewer accidents, fewer accidents means fewer deaths: Germany has far fewer motor vehicle-related fatalities (per 100,000 people) than the US.
Gee, so it isn't a human issue... so must be something else....

To get a license in Germany, you are required to take tons of driving lessons, including several where you're taken on the actual Autobahn and put into real, high-speed traffic. Drivers must receive basic first-aid training, and on top of that, you still have an incredibly difficult multiple choice exam and the road test.
To get a license in the US, you take a $300, 40 hour course, prove you can park, and pass a simple multiple choice test... is it any wonder US drivers are not "dedicated?"

Germany?s Autobahn vs US highways: COMPARED - Business Insider
https://en.wikipedia.org/wiki/List_o...ted_death_rate
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Old 01-12-18, 11:19 PM
  #43  
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Originally Posted by Ninety5rpm
There's a justice consideration too. It's one thing if they were doing something blatantly wrong like DUI or texting. But if it's just the result of an honest mistake - humans are inherently fallible - we generally don't punish in our society. That's fundamental to who we are.
As a general rule, there are four (more or less, depending on the state) culpable mental states; intentional, knowing, reckless and criminally negligent. Intentional is, by definition, not an accident. Within and beyond (even criminal negligence requires that the risk be "substantial and unjustifiable" and that "the failure to perceive it constitutes a gross deviation from the standard of care that an ordinary person would exercise under all the circumstances as viewed from the actor's standpoint") the other three lies an entire spectrum of mistakes, from "I sneezed and jerked the wheel" to "I placed my head far enough up my own rectum to keep my ears warm while driving at high speed."

Originally Posted by genec
OK, part of that same old discussion... a damn lot of those "honest mistakes" are due to just not giving a damn and not paying attention while driving...
Right. I personally think about 40% of the bad driving I see daily should be upgraded to the criminally negligent category and another 5% should be higher than that; it certainly would be if someone handled a gun with the attitude they demonstrate behind the wheel. The problem, IMO, is that as far as I can tell, the theoretical "ordinary person" has followed actual societal norms in becoming an unacceptably careless driver, so the standard devolves to permit a much lower standard of care.
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Old 01-13-18, 12:07 AM
  #44  
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Of course, the issue brought up in this topic are car designs with blind spots, and street designs with through yield signs that people aren't paying enough attention to.

One can complain all one wants about bad drivers, but part of the government's role is to look at factors that could contribute to accidents, and to use this knowledge to encourage better driving, and to modify streets to be safer.

It is likely that that little change from a yield to a stop in 2016/2017 will make a significant safety improvement at that intersection, with simply the cost of a new sign, and a bucket of paint. And, perhaps someone will also be paying enough attention to improving designs of other intersections too. Those yield signs are a cool idea, but I'm not sure they're safe, and probably of minimal actual benefit.
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Old 01-13-18, 11:07 AM
  #45  
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Originally Posted by genec
If you want to drive in Germany you need to be dedicated, which makes for better drivers. And better drivers means fewer accidents, fewer accidents means fewer deaths: Germany has far fewer motor vehicle-related fatalities (per 100,000 people) than the US.
Gee, so it isn't a human issue... so must be something else....
It looks like a large part of it number of miles driven per year:

83MM 3200 deaths 8437* mpy 38 deaths/MM
320MM 32479 deaths 13476 mpy 101 deaths/MM

* this figure is from 2002 (kinda old).

The roads are different too.

Originally Posted by genec
Thanks to Joey, for bringing this up... so other cyclists may think about it.

As a boater and boat racer, I have faced the CBRD situation quite a bit, and am quite familiar with it.

CBRD or the pillar visibility might have had nothing to do with this.

There's a hill and bushes obscuring the view and drivers are mostly going to be looking forward anyway.

Last edited by njkayaker; 01-13-18 at 11:11 AM.
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Old 01-13-18, 11:19 AM
  #46  
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Originally Posted by njkayaker


There's a hill and bushes obscuring the view and drivers are mostly going to be looking forward anyway.
The hill and bushes did not obscure the yield sign, nor cause the offending motorist to drive 37 mph through the intersection.
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Old 01-13-18, 11:30 AM
  #47  
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Originally Posted by genec
The hill and bushes did not obscure the yield sign, nor cause the offending motorist to drive 37 mph through the intersection.
Did you miss the sentence before the one you quoted?

No, the hill and bushes don't obscure the yield sign (never said they did).

I mentioned that the issue was the yield sign and I was the one who pointed out that it's now a stop sign.

I was talking about the CRBD stuff, which has nothing to do with the yield sign either.

CRBD doesn't seem to really come into play driving anyway.

Last edited by njkayaker; 01-13-18 at 11:42 AM.
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Old 01-13-18, 11:57 AM
  #48  
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Originally Posted by njkayaker
Did you miss the sentence before the one you quoted?

No, the hill and bushes don't obscure the yield sign (never said they did).

I mentioned that the issue was the yield sign and I was the one who pointed out that it's now a stop sign.

I was talking about the CRBD stuff, which has nothing to do with the yield sign either.

CRBD doesn't seem to really come into play driving anyway.
Uh, right... so as a cyclist you've never looked at a car closing in on an intersection and modified your speed to ensure that you were not there when they were?

Perhaps DRIVERS don't do this much, but then it has been long established that DRIVERS are often not great at their task.
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Old 01-13-18, 11:58 AM
  #49  
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Originally Posted by njkayaker

I was talking about the CRBD stuff, which has nothing to do with the yield sign either.
Your frustration is making you dyslexic.

It's CBDR

It might help if you spell it out for those not familiar with the term, which I've only seen in maritime applications.

It's Constant Bearing, Diminishing Range and is what the article was talking about, though compounded by the pillar.

In any case, CBDR works both ways, so we might consider it from the cyclist's perspective and apply it to avoid in being complicit in our own death.

Even if a driver can't see you hidden behind the roof pillar, you have no obstruction, and can clearly see him. CBDR applies, so if the car stays at the same angle in your field of vision, you are going to collide. Of course you know he has a stop sign and you have the right of way, but that doesn't mean you're safe unless he actually stops.

Given the speeds and distances, bicyclists don't have to slow before confirming that the car is preparing to stop. Unless he's planning to do a hard stop at the sign a driver will begin to slow in advance, which will cause his position to move back in your field of vision. Absent that cue, assume that you must make the adjustment to avoid a collision.

It's a fatal mistake to assume that the other guy will do what's needed to avoid a collision, even when you clearly have the right of way. Ultimately we have to accept responsibility for our own safety, for the simple reason that we have the most to lose.
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Old 01-13-18, 12:02 PM
  #50  
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Originally Posted by genec
Uh, right... so as a cyclist you've never looked at a car closing in on an intersection and modified your speed to ensure that you were not there when they were?
That's done at a much shorter distance than in the situation being discussed. That's able to be done without any notion of "bearing". You should already know that.
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