supcom

While I have no position on bike lanes (the vast majority of my cycling is on rural roads), I throw this bone out to the A&S dogs to chew on:

https://cycling.beloblog.com/archives..._bik.html#more

All y'all play nice now.

LCI_Brian

The caption in the first photo from the study report reads: "Figure 7.22. Typical cyclist and motorist lateral position on a wide outside lane (14 ft wide outside lane)"

Yeah, right.....

The caption in the second photo reads: "Figure 7.23. Typical cyclist and motorist lateral position on a roadway with a bicycle lane (10 ft motor vehicle lane and 4 ft bicycle lane)"

joejack951

Note that the purpose for this study was to try and justisfy adding more bike lanes in order to comply with some Clean Air Act.

LittleBigMan

How come that guy is riding in the gutter?

AndrewP

We need study of impact of bike lanes on bike and car turning events. This is when problems occur not when cars pass bikes.

Helmet Head

What they claim to have found is that even in a wide lane (without a
BL stripe), even when the cyclist is riding right up against the curb,
overtaking motorists encroach (they say "swerve") into the adjacent
lane before overtaking the cyclist. Further, they label this behavior
"over-correction by drivers", and imply there is something wrong with
doing that. I can only guess that they're assuming drivers will
"over-correct" and "swerve" into that adjacent lane even when there is
other traffic in that lane, a conclusion that does not seem to be
supported by data, reason or logic.

JohnBrooking

I agree, AndrewP. Although it sounds very scientific, the study seems to be pretty much restricted to lateral positioning on straightaways, which is not where most of the problems occur. If we take as an assumption that the bike lane is well-designed to begin with, then we can have a discussion, but as we all know, that is not always the case.

remsav

Well they do give you more room if there is no "bike lane" by this study. 9/10 vs 6/10 with "bike lane"... so if we want more passing room we should go for no bike lanes. I've seen few bikers ride that close to the gutter with a curb which seems kinda dangerous, and the numbers are probally right about people giving wide room when passing a biker. They should have noted how many people buzzed the biker by getting into the 3' space. and what happened to studying VC taking the lane and how many feet they gave when passing.

" found that cyclists on a road that provided an unmarked, four-foot lane tended to hug the curb dangerously close. Safer cyclist behavior occurred with a striped lane the same width.

Motorists in the outside, 10-foot-wide lane generally behaved similarly. Without a marked bike lane, they veered away from bicyclists, crossing into the next motorist lane nearly nine out of 10 times.

Often, they veered so far in an apparent effort to avoid a collision that they swerved a full four feet into the next motorists' lane.
"You could put a whole car between the bicyclist and them," said Hallett, an avid bicyclist who's logged thousands of miles in Austin.

With a striped bike lane, six of 10 motorists swerved, but those who swerved only encroached about 40 percent as far.
To ensure that the study findings would be broadly applicable, the CTR engineers chose volunteer cyclists of different ages, gender and cycling experience to observe during more than 8,000 passing events. The videotaping occurred last year between February and March."

mlts22 

Now all we need are laws in Austin that prohibit people from parking in bike lanes, and we're set.

galen_52657

In the left photo, other than the cyclist's position too close to the curb, the car moving over into an unoccupied adjacent lane is perfectly acceptable and proper.

sggoodri

The study basically says that drivers pass cyclists closer if there is a stripe between them than if the same width of asphalt has no such stripe. I fail to see how this closer distance is good for cyclists.

The study claims that it's bad for drivers to change lanes to give this extra room to cyclists. Why? Nowhere did they describe any near or actual collisions caused by drivers moving into the adjacent lane.

The goal of the report appears to be to increase confidence and comfort levels for motorists passing cyclists at close distance, so they don't change lanes, and to legitimize shoe-horning bike lane segregation stripes into ever-narrower widths of road.

sauerwald

The goal of the study was stated in the first paragraph of the article - "The study was conducted in Houston, Austin, and San Antonio as a way to increase bike lanes in compliance with the Clean Air Act." Therefore the conclusion that bike lanes were good was known before the study was started. In my mind, any research undertaken with the result being the given, and only the data to support it required, is not research.

Helmet Head

Exactly.

Only reason I can think of hidden agenda to promote bike lanes. Why else would they call a motrist adjusting to increase passing room as "swerving" and "over-correction", if not to justify close passing of those riding in bike lanes?

Good point.

The tragedy is how many supposed bike "advocates" will now use this study to defend their own irrational attachment to bike lanes.

sauerwald

This is fairly easy - if motorists adjust their lateral position as they pass cyclists, their chances of colliding with another motorist increase. Since less damage is done to the car when it hits a cyclist than when it hits another car, it is obviously bad for drivers to change lanes, giving extra room to cyclists.

Brian Ratliff

Talk is cheap. This study is not talk. But the forum is.

No one disputes that a skilled cyclist can take advantage of space better than an unskilled cyclist. But this study surveyed across the spectrum of typical cyclist skills. From the information given in the article (haven't finished the actual study, it's 85 pages), there is enough details about the study's controls and methods to keep from dismissing it out of hand. The conclusions also dovetail with conclusions from a study done in Florida which found that WOLs caused roadway cyclists to hug the curb and greatly increased the number of cyclists riding on the adjacent sidewalk.

But talk is cheap... Dismiss away...

As for passing distance; I'd rather have safe, but somewhat closer passes by motorists confident on my position and bearing and confident of their control than somewhat further passes by motorists who were less confident of my position and bearing and have to pass wide and watch out for me on one side and cars in the adjacent lane on the other. After all, if the motorist midjudges and hits or comes close to sideswiping a car in the adjacent lane, chances are that me, the cyclist who the car is passing, is going to come out the big loser as the passing car loses control.

Brian Ratliff

I don't get it. Data is data; what's your quarrel?

Brian Ratliff

In a word: Why?

Keep in mind: when a driver changes lanes, he needs to clear himself. That takes his attention off the cyclist, or at least splits it in the worse possible way, forcing the driver to focus keen attention in two directions, 180 degrees apart: to the front and right (for the cyclist), and to the left and back (for the lane change). This is regardless of whether the lane adjacent to the motorist is clear of traffic or not. Lane changes are also precisely the time when a driver must physically turn his head 180 degrees away from the cyclist to clear himself and cannot trust his mirrors.

Also: If the motorist miscalculates or drifts during the time when his attention is split (the motorist will tend to drift left when paying attention to the right, and drift right when paying attention to the left; and keep in mind he has to do both), the cyclist comes out the loser either way. The motorist, if he drifts left, will overcorrect to the right to avoid a car; and if drifts right, will either hit the cyclist or over correct to the left into another car. If the driver sideswipes the car to the left, then there is a good chance he will lose control of the car and hit the cyclist as well. In every case, I'd estimate that it is better than a coin toss that the cyclist loses.

We take it for granted that we want cars to move left even if there is clear room for both car and bike to travel without changing course. In reality, this causes much stress to the driver and tends toward information overload and puts the cyclist in danger.

This study is in support of my theory (same as other theories here, supported by anecdotal evidence as well as logic, but by only a couple studies, this one being one of them) that the bike lane improves safety by making traffic more predictable. As far as intersections go, a skilled cyclist can use this predictability to his advantage because the presence of a strip of paint provides a clear distinction between the cyclist being in the bike lane, out of the direct path of a car, and the cyclist taking the lane, into the direct path of an approaching car. This way, destination lane positioning is crisper (for want of a better word) and there is no ambiguity about the intent of a skilled cyclist. The painted line has the effect of providing a reference point telling the motorist exactly where the cyclist is on the road and what direction (taking the lane, falling back into the bike lane, preparing for a turn or lane change, etc.) he is headed.

Close passing is only more than a nuisance when there is not sufficent predictability; i.e. on rural highways where people seem to (hopefully only figuratively) close their eyes and step on the pedal, hoping that nothing bad happens. When there is a high degree of predictability, which a bike lane facilitates, then close passing is not an issue; or at least it is only an issue inasmuch as riding vehicularly in traffic is an issue in and of itself.

LCI_Brian

The first photo shows the furthest possible right cyclist lane position and the almost furthest possible left motorist overtaking position (without the motorist completely changing lanes). They have taken the most extreme passing distance and have labeled it as "typical cyclist and motorist position in a wide outside lane".

Also, notice the angle of the two photos. The bike lane photo looks like it was taken from the side of the road. But the wide outside lane photo looks like it was taken from the outside lane. Maybe the motorist changed lanes because he saw the photographer ahead?

galen_52657

What a total crock of crap. I NEVER turn my head 180 degrees to check anything. The car has mirrors! As a vehicle operator, you should know where all other vehicles in your proximity are at all times. If you drive like your post you must really have a hard time chewing gum and walking simultaneously.

Bekologist

the study's particulars and representative sampling, and how they present the data, make it a big enough sample. by the summation of the study, the researchers determined that

a) in a roadway without bike lane stripes, the 'typical' or average bicyclist will ride closer to the curb, and drivers will still pass further away.

b) with the addition of a bike lane, the riders position themselves in a more effective position in the roadway. the addition of the stripe AND the lane position of the bicyclist encourages safer passing by drivers.

seems pretty cut and dried. the photos show the 'typical' position in the roadways of a sample group of over 400 bicyclists. Gallup takes the pulse of the nation with merely three times that; this is an accurate portrayl on how bicyclists ride roads with and without bike lane stripes. I've seen it myself.

Brian Ratliff

Where I learned to drive, I was taught never to trust my mirror, particularly the left mirror, because of the big blind spot, when making a lane change. I got demerited on my driving test for not checking my blind spot when making a lane change into the left turn lane without turning my head to look. When did you learn to drive? And from who?

"Total crock of crap." Damn. You're rude.

Besides the head turn thing, which, at least my generation (which is now in their 20's and 30's), we were all taught to do, which part is a "total crock of crap"? The part with the split attention? The part about the drift? Or are you just into insulting people over the internet for no good reason? I hate to ask this, but did you even read my post past the first paragraph? Or do you feel that you can just insult people directly without even addressing the main point of the argument? Tell me, did I ever insult you? If it is a total crock of crap (the main points, that is, not the peripheral issue of "what a driver should do" which is what you villify everyone else for pointing out and focusing on when the argument is in "accident pseudo-analysis," but the main issue of the split attention), then you should be able to directly contradict my points and make me seem silly. Instead, you simply insult. How rude.

Are you suggesting that you blindly change lanes? Even if you split your attention between the cyclist on your right and your mirror on your left, my argument still holds up well. You neither contradicted nor argued against any of the points I made.

One last question. Did you read the study?

I did.

Brian Ratliff

If you read the study, you'd find that they were fairly thorough in describing how, exactly, they took their data. The driver did not see the photographer, and the camara was taking picture well in advance of where the driver could see the camara (>150 feet). In their study, they found that not having a bicycle lane was a very strong correlation with a far right cyclist lane postition. This was, evidently, what they found in their study as the typical case.

As for the angle thing, to get the data, they did a scaling from the video to the actual, physical roadway, taking into account camara angles and vanishing points and using reference points to the physical test sight.

You express surprise at the result, but I've seen it correlated by other studies I've personally read, and the literature review in this report correlated the effect as well, which was that WOLs tends to correlate with cyclists taking up an extreme right lane position and tend to correlate with increased passing distance by cars and more encroachment by cars into the adjacent lanes. Bike lanes have the opposite effect on both counts. Cyclists tend to take a more leftward roadway position and cars tend to give less distance when passing and encroach on the adjacent lane less. Read what you want into these results, but I'm inclined to believe the data, given that it correlates to other published studies.

Brian Ratliff

The result is not surprising. Take the case of DOS verses Windows 3.1. People fluent with the command line are few in number, but prefer DOS because of the flexibility it gives. They know how to make the best use of the command line and can accomplish tasks faster than with the icon driven Windows 3.1. Most people, however, are not fluent in the command line and don't know how to take advantage and are overcome by the steep learning curve. They are far faster with the icons than with the command line.

Now the question is whether you design roads for "skilled" cyclists who can take advantage of WOLs, or do you design it for "unskilled" cyclists who work better with bike lanes? Keeping in mind that cyclist training is not required, I'll give you a hint: Windows, and the icon driven operating system, won.

mechBgon

Easier to suck their draft.

This study may illustrate how a line on the pavement does get used as a visual straightedge to figure out who's where. We have a pinch point at 25th and Southeast where we (cyclists & motorists) funnel between a curb and a concrete center island after the bike lane ends. There's room for a car and a cyclist, but it's not easy to tell that visually from the driver's seat of a car. Motorists act nervous when we both arrive at this bottleneck at the same time, so I try to stagger my arrival and punch it to 25-30mph through the bottleneck.

Anyway, I'd be happy if they'd put a line on the pavement, even if it was just three feet from the curb, to help the motorists be more at ease. Although the lane markings are worn off half the year anyway... I emailed the city traffic guy suggesting that the lane as a whole be widened whenever the road gets worked on, too.

LCI_Brian

Yeah, I read the methodology, but I don't believe it. Look at the angle of the car in the WOL picture. It appears to be moving from the inside lane to the outside lane, probably to overtake the motorist in front.

Another thing is that the BL picture has traffic stacked up in the inside lane, limiting the amount of lateral movement for the motorist in the outside lane.