Question – Roadway Design Around Bike Lanes
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KLizotte.
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December 22, 2016 at 6:52 pm #918902
Brett L.
ParticipantHey all – looking for a quick response. Apologies
Talking with an EIT in transportation, and he’s asking me about space to avoid dooring. Without giving away too many details, I think what he’s proposing sounds alright. Would any of you be able to provide examples of locations where bike lanes are installed where dooring IS a concern, so he can see situations where the design is poor?
Cheers! Engineers are getting on board slowly too!
December 22, 2016 at 7:04 pm #1062077Judd
ParticipantCrystal Drive going Southbound in Crystal City is an example.
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December 22, 2016 at 7:10 pm #1062078Brett L.
ParticipantPerfect. Street maps capture that amazingly. You can see cars dipping into the bike lane.
December 22, 2016 at 7:18 pm #1062079TwoWheelsDC
ParticipantI St. SW is a great example. The parking lane is barely wide enough for cars, so nearly the entire bike lane is in the door zone. Frankly though, I St. is pretty much the rule and not an exception. The Clarendon Blvd. bike lanes in Arlington *almost* do it right, but the true buffer is on the traffic side not the parking side (I think it would be more useful on the parking side). There’s also some weird paint markings on the parking side that kinda look like they may be a door zone guide for cyclists, but I’m not sure of that…
December 22, 2016 at 7:50 pm #1062085CaseyKane50
ParticipantJamieson Avenue between Courthose Square and Dulany Street in Alexandria.
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December 22, 2016 at 7:59 pm #1062086Brett L.
ParticipantThanks everyone. This is enough for now
December 22, 2016 at 9:32 pm #1062096scoot
Participant@TwoWheelsDC 150793 wrote:
I St. SW is a great example. The parking lane is barely wide enough for cars, so nearly the entire bike lane is in the door zone. Frankly though, I St. is pretty much the rule and not an exception. The Clarendon Blvd. bike lanes in Arlington *almost* do it right, but the true buffer is on the traffic side not the parking side (I think it would be more useful on the parking side). There’s also some weird paint markings on the parking side that kinda look like they may be a door zone guide for cyclists, but I’m not sure of that…
+1.
Even on streets where we have space for buffers, they are often painted on the wrong side (separating the bike lane from general lanes) rather than where they are actually needed (to keep cyclists out of the door zone).
The second photo on the wikipedia dooring page shows exactly what should be avoided. Cyclists need to stay at least four feet to the left of any parked vehicle to be out of the door zone. So the right edge of a well-designed bike lane should be at least four feet away from the area marked for car storage. The vast majority of parking-adjacent bike lanes in our region are failures in this regard, and a cyclist is often wise to take the lane instead.
December 22, 2016 at 9:36 pm #1062098scoot
ParticipantSome good background on door zones and lane markings.
Edit: this video makes a strong argument for increasing the buffer distance to 5 feet.
December 23, 2016 at 2:15 pm #1062109lordofthemark
Participant@scoot 150810 wrote:
+1.
Even on streets where we have space for buffers, they are often painted on the wrong side (separating the bike lane from general lanes) rather than where they are actually needed (to keep cyclists out of the door zone).
If I am in a bike lane like that, and suspect ANY door opening activity, I will ride a bit into the buffer. I still have more “protection” from the general travel lane than I do in a conventional bike lane, and I have more distance from doors than even riding on the left edge of a conventional bike lane. And I presume its legal – if I can legally ride in the general travel lane, and can legally ride in the bike lane, I can ride in the buffer between them, no? I doubt I will ever be ticketed for that. But that only works for a cyclist who knows the danger of dooring. For newbies who use the buffered lane (and we have them to attract newbies, in part) they may stick the bike lane and avoid the buffer.
December 23, 2016 at 3:47 pm #1062112scoot
Participant@lordofthemark 150824 wrote:
If I am in a bike lane like that, and suspect ANY door opening activity, I will ride a bit into the buffer.
This is precisely my point.
Since you know the door zone is hazardous, you have learned to ride a bit into the buffer on a street designed like that. On Clarendon Blvd, I ride a bit to either side of the white line marking the left edge of the bike lane. Although I merge left whenever I see any turning vehicle blocking or parked vehicle encroaching on the bike lane within the block ahead (which means I end up taking the lane over half the time anyway).
At this point, I pretty much ignore paint everywhere: instead I ride wherever I feel safest. But there are a lot of new riders who will just ride right down the middle of a bike lane, wherever it is marked. That is why the buffer and bike lane should be switched.
December 23, 2016 at 4:41 pm #1062116Tania
Participant@scoot 150827 wrote:
At this point, I pretty much ignore paint everywhere: instead I ride wherever I feel safest. w
Yes.
December 23, 2016 at 4:44 pm #1062118lordofthemark
ParticipantI am not quite sure. I mean I guess one approach would be to skip the buffer, just make a wider bike lane, and let bike lane users decide themselves which hazard they think is greater. But I guess those best equipped to decide, the experienced riders (other than those choosing to take the general lane) can do that anyway, by riding in the buffer. (Also I guess the fear is making the bike lane too wide would cause some drivers to perceive it as another general travel lane) The issue is how we guide the newbies by placement of the buffer, and whether, if local govt practice prevents us from getting the buffer where we want it, is it worth biking advocates supporting the buffered lane anyway, over a conventional lane, or over a sharrows/nothing.
My sense is that many local govts see conflicts between bikes and moving vehicles as a bigger issue than dooring, regardless of data on dooring incidents. There may also be the issue that distance from moving traffic is more of an issue for making newbies comfortable riding in the street at all. So while we probably should advocate for switching the buffer side, we still need to determine what to do when local govt won’t budge on that. I tend to think that the bad buffered lane is still better than a conventional lane, because the newbs are no worse off, and some folk who might not avoid the lane entirely will ride into the buffer. And those who ride within the lane, though with no better dooring protection than a conventional striped lane, will at least have better separation from the general travel lane.
I am also not absolutely convinced that striping a bike lane has no impact on dooring behavior. I am not aware of any data on this particular question, so this is speculation, but I imagine that the presence of a striped bike lane serves as a reminder to parkers that bikes are likely to be present, and may cause greater caution. That is not to say that dooring is not a concern when designing bike infra, but that the data on overall incidence of dooring MAY not be reflective of likelihood of dooring incidence on bike lanes. (that is also why I am much more likely to take pains to avoid the door zone on streets without bike lanes, even though I will ride in a door zone bike lane in many places)
December 23, 2016 at 6:09 pm #1062128KLizotte
Participant@lordofthemark 150833 wrote:
I am not quite sure. I mean I guess one approach would be to skip the buffer, just make a wider bike lane, and let bike lane users decide themselves which hazard they think is greater. But I guess those best equipped to decide, the experienced riders (other than those choosing to take the general lane) can do that anyway, by riding in the buffer. (Also I guess the fear is making the bike lane too wide would cause some drivers to perceive it as another general travel lane) The issue is how we guide the newbies by placement of the buffer, and whether, if local govt practice prevents us from getting the buffer where we want it, is it worth biking advocates supporting the buffered lane anyway, over a conventional lane, or over a sharrows/nothing.
My sense is that many local govts see conflicts between bikes and moving vehicles as a bigger issue than dooring, regardless of data on dooring incidents. There may also be the issue that distance from moving traffic is more of an issue for making newbies comfortable riding in the street at all. So while we probably should advocate for switching the buffer side, we still need to determine what to do when local govt won’t budge on that. I tend to think that the bad buffered lane is still better than a conventional lane, because the newbs are no worse off, and some folk who might not avoid the lane entirely will ride into the buffer. And those who ride within the lane, though with no better dooring protection than a conventional striped lane, will at least have better separation from the general travel lane.
I am also not absolutely convinced that striping a bike lane has no impact on dooring behavior. I am not aware of any data on this particular question, so this is speculation, but I imagine that the presence of a striped bike lane serves as a reminder to parkers that bikes are likely to be present, and may cause greater caution. That is not to say that dooring is not a concern when designing bike infra, but that the data on overall incidence of dooring MAY not be reflective of likelihood of dooring incidence on bike lanes. (that is also why I am much more likely to take pains to avoid the door zone on streets without bike lanes, even though I will ride in a door zone bike lane in many places)
Unfortunately newbie riders have a bad tendency to ride in the door zone though I can’t say whether a bike lane makes that tendency worse or the same. I like bike lanes only when there is sufficient room for me to ride within the lane but outside of the door zone and still provide drivers sufficient space to pass me easily. Otherwise I’d rather take the lane rather than feel squeezed into an unsafe space.
There is a bike lane in front of my apartment building’s driveway. The lane always reminds me to check my right mirror when turning into the driveway for cyclists coming up my flank. I should always remember to do that wherever I am but I must admit that I often forget if a bike lane doesn’t exist.
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