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I studied the safety impacts of new bike ways in Los Angeles, and found that sharrows reduced collision rates just as well as bike lanes. https://blueskiesabove

I studied the safety impacts of new bike ways in Los Angeles, and found that sharrows reduced collision rates just as well as bike lanes. https://blueskiesabove.us/entry/to-live-and-ride-in-la-do-bike-lanes-make-angelenos-safer/ https://blueskiesabove.us/entry/to-live-and-ride-in-la-do-bi... (I emailed this to the author a few days ago.) I’m not saying these findings would hold up with better ridership data. But they were surprising findings, nonetheless. Plus, nobody wanted to hear it.

CamperBob2 6y ago
Did you control for the added publicity (some of it substantial) surrounding the addition of sharrows? I know it was a big deal in the Seattle area when they started to appear. Maybe the benefit was due to a temporary spike in public awareness, and if so, the risk level will fall back to baseline soon enough if it hasn't already. First rule of bicycle safety: "Paint won't save you."
- ryantgtg 6y ago
  No, but there was not positive publicity for sharrows in Los Angeles. Everyone either hates them, or are unaware of them (I’ve spoken with a few drivers who said they have never noticed them). I think the benefit is likely due to increased numbers of cyclists on those routes (and other routes - just a general heightened awareness of bicyclists).
dfgdghdf 6y ago
"Sharrows" don't provide the main advantage of a dedicated bike lane: a feeling of subjective safety. The majority of people consider the roads too dangerous to cycle on and only a dedicated space will fix that.
- ryantgtg 6y ago
  More likely, only a dedicated path, not a lane, will fix that.
- toast0 6y ago
  Bike lanes are a double edged sword. Yes, there's subjective safety, but as much as the white line (or sometimes more) holds cars out, it also holds bikes in. Once you have a condition where you need to move left, out of the bike lane, it's a big step. But depending on your route, you may need to avoid pavement issues, trash or other debris in the bike lane, vehicles crossing the lane, or you may need to turn left or pass slower bicycles. And the aditional problem that if there's a marked bike lane, drivers will expect bicycles to remain in it. Sharrows don't provide subjective safety, they just remind everyone that bicycles are allowed there, and should be expected there. (Of course, when they're marked too far to the right, it's worse than not having any markings)
  - dfgdghdf 6y ago
    This is an interesting point, and it was made by UK cycling bodies back when the private car had only just started to dominate UK streets. They argued that dedicated bike paths would limit the freedom of cyclists, since they would be obligated to use these paths. In hindsight, this was a missed opportunity to build this infrastructure at a time when cycle usage (and therefore public support) was very high... and cycle participation has plummeted in the decades since to 1.7% of all journeys. Now, cyclists have the right to use all UK roads (except motorways), but only the bravest actually do so. Meanwhile, the Netherlands has fantastic cycle infrastructure and participation is very high - although still lower than it once was in the UK! I don't think it is hyperbolic to say that given what we now know about climate change, harmful emissions and the health consequences of inactive lifestyles, this is a national tragedy. Good cycle infrastructure encourages more people to cycle, and the rights of cyclists are better protected in societies where more people cycle.
  - bnralt 6y ago
    A car making a right turn is also going to be a lot more dangerous situation when there are bike lines than if the bicycles are sharing lanes with cars. I was curious about how it's handled in Copenhagen (since that is usually held up as a particularly bike friendly city), but it seems to be an issue there as well, according to this article[1]. What's interesting about this article is that it suggests that a large part of the bike safety efforts are directed at getting cyclists to adopt safe behaviors. It seems like most of the discussion in states is directed at everyone except the cyclists themselves. [1] http://www.cycling-embassy.dk/2015/10/23/how-to-decrease-right-turn-accidents/ http://www.cycling-embassy.dk/2015/10/23/how-to-decrease-rig...
deleted 6y ago
[deleted]
dietr1ch 6y ago
If I were told I had died from a bike accident when biking to work, I'd be betting really hard on that I was not on a dedicated bike lane..
- ryantgtg 6y ago
  If that happened, according to the SWITRS data you were most likely within an intersection. So yes, not within a bike lane.
  - dietr1ch 6y ago
    Is there data that suggests how to fix intersections? I (used to :/) bike to work daily and was mostly scared of the intersections where the right lane crosses the shoulder/bike-lane to give drivers a quick right turn. A co-worker almost died on the scariest one after getting hit from behind, but was lucky enough to roll next to the car and only lose the bike. Other risky ones are where the driver that's merging in won't expect a bike and suddenly blocks the bike lane to get a better view of the traffic. This generally happens on the long streets with fast traffic 45m/h+ as few bikers take the risk making it more likely that drivers "forget" that there's bike traffic.
    - ryantgtg 6y ago
      There is a design treatment called protected intersections that slows vehicles turning, increases visibility of bicyclists, and gives them some physically protected buffers. https://altago.com/wp-content/uploads/Evolution-of-the-Protected-Intersection_ALTA-2015.pdf https://altago.com/wp-content/uploads/Evolution-of-the-Prote... Additionally, you can continue the bike lane paint within an intersection. But I don’t recall the data on that. And yeah, those mixing zones are a disaster, especially when the bike facility completely disappears 100 feet before the intersection.
      - joveian 6y ago
        A more basic fix that I've seen is to have a bike light and not let bike traffic and right turning car traffic proceed at the same time (and thus not have the bike lane cross the right turn lane before the intersection). For limited particularly bad intersections this seems to work well. Occasionally they have just prohibited right turns at certain places. I think I've seen one or two of the fancier protected intersections but they are rare around here. I recall seeing an analysis where several of the most deadly intersections were down a hill where cars turn right occasionally. Drivers have trouble figuring out the speed of the cyclists in that situation. I do avoid one local intersection that I would otherwise use frequently because they haven't done anything and a large percentage of the time I pass through it cars get too close to me or someone else. In that case, part of the issue is that cars are effectively going from a freeway to a street level highway that turns into a freeway. Even though drivers here are generally much more chill than any other city I've lived in or visited, put them in a "near freeway but street level" situation and they will try to run you over. Here they have been continuing bike lanes in intersections more often lately. I think they have often just used dotted white lines and do not use them both directions even if there are bike lanes both ways. I wouldn't be surprised if stuff like that and sharrows do nothing at all in any particular location but if there are enough of them all over the place might help remind drivers that cyclists exist. Or maybe they don't really do anything ever :/.
mlinksva 6y ago
Has anyone done a survey paper on the impact of sharrows? I skim papers on sharrows when (very occasionally) I come across one, but they seem to be based on a small dataset from one city. I personally treat them as preferable to nothing, and except on really busy streets, preferable to door zone bike lanes. Of course there are options better than either, and I prefer those. But I also don't really think bicycle affordances are the solution -- a legal/policy war on cars and drivers is.
tmcw 6y ago
Sorry for the delay updating the article - one heck of a week. I've linked it and added a few more notes from folks who wrote back.

CamperBob2 6y ago

Did you control for the added publicity (some of it substantial) surrounding the addition of sharrows? I know it was a big deal in the Seattle area when they started to appear. Maybe the benefit was due to a temporary spike in public awareness, and if so, the risk level will fall back to baseline soon enough if it hasn't already. First rule of bicycle safety: "Paint won't save you."

ryantgtg 6y ago
No, but there was not positive publicity for sharrows in Los Angeles. Everyone either hates them, or are unaware of them (I’ve spoken with a few drivers who said they have never noticed them). I think the benefit is likely due to increased numbers of cyclists on those routes (and other routes - just a general heightened awareness of bicyclists).

dfgdghdf 6y ago

"Sharrows" don't provide the main advantage of a dedicated bike lane: a feeling of subjective safety. The majority of people consider the roads too dangerous to cycle on and only a dedicated space will fix that.

ryantgtg 6y ago
More likely, only a dedicated path, not a lane, will fix that.
toast0 6y ago
Bike lanes are a double edged sword. Yes, there's subjective safety, but as much as the white line (or sometimes more) holds cars out, it also holds bikes in. Once you have a condition where you need to move left, out of the bike lane, it's a big step. But depending on your route, you may need to avoid pavement issues, trash or other debris in the bike lane, vehicles crossing the lane, or you may need to turn left or pass slower bicycles. And the aditional problem that if there's a marked bike lane, drivers will expect bicycles to remain in it. Sharrows don't provide subjective safety, they just remind everyone that bicycles are allowed there, and should be expected there. (Of course, when they're marked too far to the right, it's worse than not having any markings)
- dfgdghdf 6y ago
  This is an interesting point, and it was made by UK cycling bodies back when the private car had only just started to dominate UK streets. They argued that dedicated bike paths would limit the freedom of cyclists, since they would be obligated to use these paths. In hindsight, this was a missed opportunity to build this infrastructure at a time when cycle usage (and therefore public support) was very high... and cycle participation has plummeted in the decades since to 1.7% of all journeys. Now, cyclists have the right to use all UK roads (except motorways), but only the bravest actually do so. Meanwhile, the Netherlands has fantastic cycle infrastructure and participation is very high - although still lower than it once was in the UK! I don't think it is hyperbolic to say that given what we now know about climate change, harmful emissions and the health consequences of inactive lifestyles, this is a national tragedy. Good cycle infrastructure encourages more people to cycle, and the rights of cyclists are better protected in societies where more people cycle.
- bnralt 6y ago
  A car making a right turn is also going to be a lot more dangerous situation when there are bike lines than if the bicycles are sharing lanes with cars. I was curious about how it's handled in Copenhagen (since that is usually held up as a particularly bike friendly city), but it seems to be an issue there as well, according to this article[1]. What's interesting about this article is that it suggests that a large part of the bike safety efforts are directed at getting cyclists to adopt safe behaviors. It seems like most of the discussion in states is directed at everyone except the cyclists themselves. [1] http://www.cycling-embassy.dk/2015/10/23/how-to-decrease-right-turn-accidents/ http://www.cycling-embassy.dk/2015/10/23/how-to-decrease-rig...

deleted 6y ago

[deleted]

dietr1ch 6y ago

If I were told I had died from a bike accident when biking to work, I'd be betting really hard on that I was not on a dedicated bike lane..

ryantgtg 6y ago
If that happened, according to the SWITRS data you were most likely within an intersection. So yes, not within a bike lane.
- dietr1ch 6y ago
  Is there data that suggests how to fix intersections? I (used to :/) bike to work daily and was mostly scared of the intersections where the right lane crosses the shoulder/bike-lane to give drivers a quick right turn. A co-worker almost died on the scariest one after getting hit from behind, but was lucky enough to roll next to the car and only lose the bike. Other risky ones are where the driver that's merging in won't expect a bike and suddenly blocks the bike lane to get a better view of the traffic. This generally happens on the long streets with fast traffic 45m/h+ as few bikers take the risk making it more likely that drivers "forget" that there's bike traffic.
  - ryantgtg 6y ago
    There is a design treatment called protected intersections that slows vehicles turning, increases visibility of bicyclists, and gives them some physically protected buffers. https://altago.com/wp-content/uploads/Evolution-of-the-Protected-Intersection_ALTA-2015.pdf https://altago.com/wp-content/uploads/Evolution-of-the-Prote... Additionally, you can continue the bike lane paint within an intersection. But I don’t recall the data on that. And yeah, those mixing zones are a disaster, especially when the bike facility completely disappears 100 feet before the intersection.
    - joveian 6y ago
      A more basic fix that I've seen is to have a bike light and not let bike traffic and right turning car traffic proceed at the same time (and thus not have the bike lane cross the right turn lane before the intersection). For limited particularly bad intersections this seems to work well. Occasionally they have just prohibited right turns at certain places. I think I've seen one or two of the fancier protected intersections but they are rare around here. I recall seeing an analysis where several of the most deadly intersections were down a hill where cars turn right occasionally. Drivers have trouble figuring out the speed of the cyclists in that situation. I do avoid one local intersection that I would otherwise use frequently because they haven't done anything and a large percentage of the time I pass through it cars get too close to me or someone else. In that case, part of the issue is that cars are effectively going from a freeway to a street level highway that turns into a freeway. Even though drivers here are generally much more chill than any other city I've lived in or visited, put them in a "near freeway but street level" situation and they will try to run you over. Here they have been continuing bike lanes in intersections more often lately. I think they have often just used dotted white lines and do not use them both directions even if there are bike lanes both ways. I wouldn't be surprised if stuff like that and sharrows do nothing at all in any particular location but if there are enough of them all over the place might help remind drivers that cyclists exist. Or maybe they don't really do anything ever :/.

mlinksva 6y ago

Has anyone done a survey paper on the impact of sharrows? I skim papers on sharrows when (very occasionally) I come across one, but they seem to be based on a small dataset from one city. I personally treat them as preferable to nothing, and except on really busy streets, preferable to door zone bike lanes. Of course there are options better than either, and I prefer those. But I also don't really think bicycle affordances are the solution -- a legal/policy war on cars and drivers is.

tmcw 6y ago

Sorry for the delay updating the article - one heck of a week. I've linked it and added a few more notes from folks who wrote back.