Helmet Head

In order to stop engaging in discussions about "using DLLP to avoid inadvertent drift collisions" in every thread in which it seems relevant, I would like to devote this one thread to that topic, and stop engaging in this debate in other threads.

I will start by presenting the theory (a "hypothesis" in scientific terms). This includes some definitions of terms that I use, the premises the theory is based on, the reason, conclusions, and some FAQs. I hope this helps.

Definitions

• ruralish - any non-urban road with long stretches of no intersections.
• DLLP - Dynamic Lateral Lane Positioning - a cycling methodology that emphasizes use of lateral lane positioning for improving the cyclist's sightlines to potential hazards, conspicuity and predictability.
• look back - A clear and obvious look back over your shoulder for longer than "just a glance".
• merge - moving laterally in a safe and predictable fashion... for a bicyclist that means only after looking over the shoulder on the side on which he plans to move in order to verify it is clear and safe to make the move.
• weaving - to move back and forth between two lateral positions with a period of less than 10 seconds.
• fog line - a stripe at the edge of the road that vehicle drivers are not supposed to cross.
• shoulder - any paved portion of the road to the right of the fog line.
• bike lane - a shoulder that is designated by signs and/or markings to be a "bike lane".

Premises (to determine the validity of the argument, these are assumed to be true; to determine the soundness of the argument, it must be valid and these premises must be accepted to be true):

1. In a "ruralish" (non urban) environment on a quiet low traffic open highway with good sight lines, a potential obstacle up ahead in a motorist's intended path in his lane is much more likely to be relevant to that motorist than is the same object up ahead in the shoulder or bike lane.
2. We are much more likely to notice things which are relevant to us in some way.
   Source: https://www.visualexpert.com/Resource...blindness.html
3. If you're more likely to be noticed, you're less likely to be overlooked.
4. A contributing factor in the type of inadvertent drift collisions cited in the bike lane deaths thread is the motorist overlooking the presence of the cyclist
5. Another factor in those inadvertent collisions is the motorist choosing to attend to a distraction that he probably would not choose to attend to, or would not choose to attend to as long, if he had noticed and was aware of the cyclist up ahead.
6. The inadvertent drift collisions occur when the distracted motorist drifts into the shoulder or bike lane while attending to a distraction.
7. On long straight stretches of road, motorists who are following someone else relatively closely (i.e., gap to vehicle in front of them is less than 5 seconds) are much less likely to choose to take their eyes off the road for a long enough time to drift significantly out of their path than are motorists who have an relatively empty road (intended path is clear from vehicle to point that they won't reach for at least 5 seconds) in front of them; the longer the gap, the more likely they are to take their eyes off the road to attend to a distraction for a long enough time to significantly drift out of their path.
8. There is no legal requirement for cyclists to "keep to the right" when same direction traffic is not present.
9. On most ruralish narrow roads with no shoulders, it is safe to cycle there even though doing so requires every approaching motorist to notice the cyclist in order to not hit him.

Reasoning:

1. Per A, a cyclist up ahead in a motorist's intended path in his lane is much more likely to be relevant to that motorist than is the same cyclist riding up ahead in the shoulder or bike lane.
2. Per B, the cyclist that is more relevant is more likely to be noticed by the approaching motorist.
3. Per C, the cyclist that is more likely to be noticed is less likely to be overlooked.
4. Per D, E and F, the cyclist who is less likely to be overlooked is less likely going to be inadvertently drifted into.

Conclusion
Per the above reasoning, it's safer to be up ahead in the motorist's lane than up ahead in the shoulder or bike lane: you're more likely to be noticed, and therefore less likely to be inadvertently drifted into.

Therefore, what I often do when there is no same-direction traffic is merge left into the main traffic lane, and stay there until I notice with my mirror faster traffic approaching from behind. When they are about 10 seconds back, I do a right shoulder check and move back into the shoulder or bike lane.

FAQ

1. Why would you want to weave back and forth in and out of the lane like that? It's not weaving. The technique normally involves maintaining a given lateral position for at least 10 seconds, almost always much longer, before moving back to the other position.
2. If you're in the shoulder or bike lane being passed by cars, and then there's a gap, what is the minimum that gap has to be in order to move back into the traffic lane? I will rarely move back into the traffic lane unless I can see that the gap to the next vehicle approaching from behind is at least 20 seconds. If it's less than that, I might move out to the right tire track for a few seconds, then move back, just to increase the chances of them seeing me, demonstrating look backs and clear arm signalling for each merge.
3. Would you do this without a mirror? Only on quiet slow roads. On roads with fast traffic (35+ mph speed limits), I would not do it without a mirror.
4. How does a shoulder that is safe for cycling while being passed by motorists become less safe when same-direction faster traffic is not present?. During the gaps in same-direction traffic, the next motorist to be approaching is more apt to paying less attention to the road (see Premise G above), and, therefore, more likely to take his eyes off the road long enough to drift into the shoulder or bike lane. That's why it's less safe to be in the shoulder during gaps in same-direction traffic.
5. It seems like a lot of work. Is it? You say "work", I say "paying attention", and that's a good thing. In a shoulder or bike lane it's all too easy to lapse into a mindless wandering of thoughts where we can become as oblivious to traffic as some of the overtaking motorists are to our presence. That's not good. Staying engaged in DLLP helps keep the cyclist alert and paying attention to what is going on around him. That's good. It's good to notice in your mirror that there is no same-direction traffic and to move out into the main traffic lane, and to pay attention with your mirror (a microsecond glance every 3-5 seconds all it normally takes) to note when traffic is approaching from behind, and to move out of the way when you've been out there long enough in their path for them to have been very unlikely to still not have noticed you.
6. If a driver is not paying attention, how is he going to notice you regardless of where you are riding? Drivers periodically and frequently, if not constantly, pay attention to their intended path, or they would be driving off the road all the time. The point of this technique is to do be out their in their intended path long enough so that it would be virtually impossible for them to notice you, because that would mean they were not paying attention to their intended path for so long, there is no way they could stay on the road.
7. But this technique is supposedly about avoiding "inadvertent drift", which is exactly that - drivers not paying attention to the road so long that they can't stay on the road. It's a timing thing. What you want to do is try to get their attention when they're still so far back (more than 20 seconds), that if they're already not paying attention at that point, they'll drift off the road and crash long before they reach you. Odds are, that that's not going to happen, and one of their periodic/frequent checks on the road ahead is when we're counting on being noticed. If, instead, during one of those checks, we're in the shoulder, then we're much less likely to be noticed. That's the point of this technique: to be in the space where the motorist is paying attention when he's paying attention..
8. But since some motorists are not expecting to see a cyclist in the road up ahead, aren't we prone to inattentional blindness when we're in the road? First, the expectations for cyclists in the road is probably not any signficantly different on the narrow roads, yet they don't seem to hit cyclists on those roads because of inattentional blindness. Second, the technique involves moving aside into the shoulder to be considerate and to accomodate their easier passing of us. In the highly unlikely event that they haven't noticed us despite us being in their path, it doesn't matter, because we're moving out of their path anyway (as opposed to what we do on narrow roads - stay in their path). Finally, the likelihood of the motorist not seeing the cyclist in his path, combined with the low likelihood of the DLLP cyclist not noticing the approaching motorist in his mirror, and so staying in his path and not moving aside, becomes an extremely unlikely event. See the bike lane deaths thread for examples of much more common (and therefore more likely) events.
9. The difference in angle of vision between a cyclist up ahead in the shoulder and a cyclist up ahead in the traffic lane, when the motorist is 20 seconds back, is so light, how can one cyclist be more noticable than the other? The argument has nothing to do with angles (which has to do with sensory conspicuity) and everything to do with relevance, a key aspect of cognitive conspicuity. That's not to say that relevance is required to be noticed, just that relevance makes something much more likely to be noticed (see Premise B). What makes a cyclist up ahead relevant to motorist is not whether he can see him (because we're assuming he can see the cyclist), but where the cyclist is relative to where the motorist is going (or at least thinks he's going). It is normal and natural for the subconscious mind to assume that a cyclist in the bike lane or shoulder is going to continue riding in the shoulder, and that the motorist will not enter the shoulder, and, therefore, the cyclist is not relevant to the motorist.
10. Are you suggesting the primary reason one should move left is to improve conspicuity? - Robert Hurst No. See explanation in Post #66.

Changes
I reserve the right to update the presentation of this theory in this OP, but will always note edits here in this section, and, when signficant and appropriate, will make a post about the change.

• Added FAQ #5, #6, #7, #8, #9
• 10/1/06: FAQ #10; revised description of what "Premises" are from must be taken on faith to must be assumed to be true.
• 10/2/06: Updated premises description again.
• 10/4/06: Added sightlines to DLLP definition.

Bekologist

is this the new thread about using the "PEEK-A-BOO" trademarked weaving techniques?

Bekologist

i think it is very hardly relevant unless you are so paranoid, and fail to use adequate absolute conspicuity devices.

Helmet Head

(this is from another thread, a discussion on this topic)

The fact that the reason cyclists ride in the the path of all same-direction faster motorists on narrow roads with no shoulders is "out of necessity" is irrelevant to the point that despite doing it, and regardless of why they do it, it is safe. If riding in the path of fast approaching motorists is safe on narrow roads where they can't and so don't ever get out of the way, why would it be unsafe on roads where they can and almost always would get out of the way? The reason they would get out of the way, be the way, is not for safety purposes, but to be considerate. Why be in the way for no reason?

SSP

We're talking about why you would insist upon moving your bike into the roadway (with all the requisite "signals" and "look backs"), when it's much easier to ride a straight, predictable line on a wide shoulder or BL.

Yes...we all ride in the travel lane when necessary. But that's not relevant to your theory of DLLP...you're asserting that it's safer than the alternative. But other than your theory and your Wall of Words(tm), you've not convinced me (nor, apparently, anyone else) that it enhances cycling safety.

Brian Ratliff

HH: Why did the argument restart? We were all discussing precisely your premises which others did not agree with. We were also adding to the premise list things that we thought were relevent but not included in your theory - and changes the outcome of your logical progression. I still think you are still just looking for justification from the forum. I hear blogs are good for that. But forums... no, here, you tend to get raw opinions. Which you seem not to like so much.

So, is this a discussion of effectiveness of "DLLP," a discussion of your list premises which might be flawed and are almost certainly incomplete, or are you simply looking to install a Wikipage onto the Bike Forums?

Aw well, for the record, if someone wants to know some of my arguments regarding this topic, I'll refer you back to the Logging trucks, one bike, and a twelve foot shoulder. thread. Search for my name. I'm not going to repeat my words just to satisfy an ego. Other arguments are scattered in other various threads.

vrkelley

Yes this is PAB-101...you in the right place, my friend. Now start weaving

Helmet Head

Well, the main reason to merge left into the main traffic lane out of the shoulder or bike lane is always to make yourself more conspicuous to potential cross traffic, including to improve your sight lines to them. On these "ruralish" roads, there are fewer intersections and so the threat from cross traffic is lower, but it's still there. If you're out in the traffic lane, you'll see the intersections sooner, and your angle will be better to see someone pulling out sooner, and for them to see you sooner (not to mention them being more likely to notice you because you're riding where they're more likely to be paying attention, rather than in the shoulder where they're less likely to be paying attention).

Of course, the argument to use a more conspicuous position in the main traffic lane to reduce the likelihood of falling victim to inadvertent drift is presented in the OP of this thread.

And one of the FAQs touches on the advantage of using this technique to stay more alert.

After reviewing this more detailed presentation of the argument, including reading the FAQs, I would be interesting in knowing why you don't find it persuasive.

Helmet Head

To present it more completely and because there were too many separate discussions going on.


We were? Now here, see, you can specify exactly which premise you disagree with by letter, and explain why.

That makes no sense. Either the logic follows from the specified premises, or it doesn't. If it doesn't, adding additional premises are not required to show that. If it does, then adding additional premises can't change that.

I'm looking for explanations as to why my argument is or is not persuasive. I could care less about "justification from this forum".

It's a presentation of an argument. I'm requesting comments. If you don't accept one or more of the premises, I want to know why. If you think the reasoning and conclusions don't follow from the premises, I want to know why. This is original thinking, so it definitely does not belong in Wikipedia. If this is not appropriate for this forum, I don't know what is.

I believe I already addressed all of your arguments, and you did not respond to my comments. If not, then I inadvertently missed something. Let me know.

SSP

Because:

1) I don't believe it materially increases my conspicuity or relevance.

2) Because of that, I don't belive that it would materially increase my safety.

3) By your own admission, it's limited to a very small proportion of roadways (i.e., "ruralish" roads with very low traffic volumes, fairly low speeds, and wide shoulders).

4) It's more work on my part (much more signalling and head turning when I could just be pedalling along in a comfy WOL/BL lane enjoying my ride).

5) I think it's better to ride in a straight line, instead of weaving in and out of the primary travel lane.

6) I'm not infallible...weaving in and out of the traffic lane just doesn't seem to be a very smart proposition.

7) AFAIK, you are the lone voice in cycling advocacy who is advancing this technique. Until and unless you can convince a significant body of authorities to embrace your theory, I'll remain skeptical that it's anything more than one man's obsession.

Brian Ratliff

HH - for the sake of completeness then: repost all the counter argument threads from myself, John, Bek, sbhikes, and all the others. Or at least summarize them (edit: on second thought, I don't trust your summaries; you've spun them before. Exact quotes please). Then go down point by point and respond to all of our exact arguments. If your intent is truly to get feedback, you need to post all other arguments and your response to those arguments.

Fact is though, you spent far more time whining that everyone was "misreading" you, and you spent precious little time addressing true arguments or coming up with novel arguments supporting your "theory." You were the one who shifted threads. It is up to you to do the labor. You frequently complain how long you spend responding to a comment. Well, certainly all of us have spent time as well; I, for one, am loath to repeat it just because you have it in your mind to change venues.

Oh, and please use direct quotes from throughout all the 472 posts to the previous thread; no paraphrasing, since you frequently complain about people paraphrasing yourself. Otherwise, this is just a dodge, pure and simple. Just a tactic to put this, once again, on center stage, simply hoping you get less resistance because people are tired of arguing with you and making your argument appear more persuasive by dint of people simply getting tired.

What a dodge...

Helmet Head

Brian, show me one post from you or John in that thread that addresses this argument to which I did not respond, and you're on.

By the way, I spent a lot of time reading what John wrote, and explained at length why most of it was completely irrelevant to this argument. And about half of that thread was eaten up by John coming up with one lame excuse after another for not accepting the truth of the one statement I quoted from the inattentional blindness article (see Premise B above). Page after page I explained fully why each excuse was so lame. He never stuck to a single excuse. He kept conjuring new ones. The last one was completely pathetic (he was assuming a different meaning from the one Green was using), and that's where it ended. Why bring all the garbage into this thread.

While both of you made very interesting comments, none of them addressed this argument that I did not refute. Plus, some of what was learned in that thread, and the 2 or 3 others where this was discussed recently, have been incorporated into this presentation of the complete argument. That's what I want addressed. Am I missing anything here? That's what I want to know. If you don't want to help, fine.

Helmet Head

Well, since the odds of falling victim to inadvertent drift are so low, you're right. But I believe there is a significant benefit with respect to reducing risk with cross traffic. But even for inadvertent drift, seriously, I am alarmed at how many serious/experienced cyclist lives seem to be taken by this type of collision. See the bike lane deaths thread.

Actually, most arterials in San Diego fall into this category during most times of the day. I can't speak for your area.

Did you see FAQ #5?

Did you see FAQ #1?

I know it doesn't seem "very smart", or whatever, that's why I presented the argument in this OP.

Fair enough. But I have to start somewhere, and this is where. That's why I'm trying to understand what exactly about my argument is not compelling. Thanks for your input.

Cyclaholic

*bolding of 'faith' is mine.

A faith based belief is neither a hypothesis nor a theory, it's a religion or a cult. Furthermore, your premises are either irrelevant to your conclusions, or simply unfounded. Take the article in premise B for example. There is nothing in the article which indicates that positioning of the item of interest to us bears any relevance of our cognition of it - like the ground quickly approaching in the windscreen of an airliner and ground proximity warning sounding in the cockpit yet the pilot hit the ground. Interestingly, the article states that "Humans who hold a belief or expectation tend to seek evidence which confirms and ignore or avoid evidence which refutes." which sounds like a summary of many of your posts.

My conclusion is that you're promoting taking the lane needlessly then moving out of the travel lane as motorists approach, something which is impossible to do if there is no shoulder/WOL but would require moving onto the sidewalk (if there is one).

In my opinion you are conditioning motorists to expect any cyclist in the travel lane to move out of the lane for them so that the motorist donesn't need to adjust their lane position to accomodate the cyclist. You're in effect reinforcing the belief that cyclists either don't belong on the road or that motorists have absolute right of way over cyclists. So what happens when there is no shoulder or bike lane? the drivers' conditioned expectation is not met so becomes annoyed/agressive towards the cyclists.

Helmet Head

All hypotheses are based on premises that must be taken on faith.

You have to start somewhere. You can't prove everything.

sbhikes

This topic is boring. I would rather we disucss how many 20 dollar bills you need for a proper fan. Bek, you are our expert. Tell us how much cash do you flash when you're trying to piss off the motorists on your route?

vrkelley

Cute? Yes! Scientfic? No. Why? Because there's no evidence i.e., actual traffic studies (from this century) or personal ride studies to support the reasons/FAQs. Expected studies would be:
On roadstyle X, I tried 100 weaves...my observations were Y

But thanks for posting.

vrkelley

It's your theory,you prove it. And if no one else has done it...how about reporting back after you've done say 1,000 weaves under various riding conditions. I'm not about to risk my hide.

EDITED: It looks like there are already 2 strong personal studies disproving your theory.

https://www.bikeforums.net/advocacy-safety/231399-observations-daytime-static-lane-positioning.html Observations from some real-world "Static-Lane-Positioning"
https://www.bikeforums.net/advocacy-safety/231287-observations-some-real-world-static-lane-positioning-testing.html Observations of daytime, static-lane positioning

Bekologist

..i like to use at LEAST 100 bucks in twenties for an effective fan, maybe a couple more if i have to play "PEEK-A-BOO" to maximise my conspicuity. maybe canadian twenties would work better?

tomcryar

Would travelers checks work better? Stiffer paper and all. Just my "theory".

Cyclaholic

Oh no! haven't you been paying attention? according to the high priests of the DLLP faith you want those loose floppy bills to dynamically move in and out of the travel lane. Floppy bills = good.... its my DBP (Dynamic Bill Possitioning) theory, you'll have to have faith brother coz there aint a shred of proof.

Blue Order

So has anybody bothered to read all the way through the first post?

ryanparrish

I don't even know why I began reading this post. At least I can now rest that the giant mystery to DLLP has finally been solved.

YAWWWWWWWNNNNN

tomcryar

As soon as I saw "ruralish" I stopped................

vrkelley

RE thread title..."Avoid inadvertent drift collisions" Try my theory instead...Dynamic Unilateral Moving Bike theory - You do the math