road widths: sharrows vs. bike lanes

[scoot]

This topic came up in the Crystal Drive discussion, but is better suited to a new thread:

For roads with parallel parking and a single general vehicle lane in each direction, how much space is needed for vehicles to safely pass bicycles without crossing the yellow lines? At what width do sharrow markings become preferable to painted bike lanes?

IIUC, a general rule for lane widths is that any single lane less than 14′ too narrow for a bike and a motor vehicle side by side, and riders are thus advised to take the full lane whenever it is less than 14′.
Examples (two-lane): most of the roads through Fort Myer, Lake Barcroft area, etc.
Examples (multi-lane): Columbia Pike, most of S Walter Reed, most of George Mason Drive

But that rule assumes no parked cars. Consider the following configuration: 10′ travel lane, 5′ bike lane, parallel parking. Parked cars will render most of the bike lane useless. Some may venture a bit closer, but I always keep at least 4 feet from parked cars, so I end up riding with wheels on the white line in most door-zone bike lanes (e.g. 34th Street S through Fairlington). However, riding on or near that line invites very close passes from drivers who are afraid to cross the yellow lines.

Seems to me that wherever the right boundary is adjacent to car doors, anything less than about 16′-17′ total should be marked as a sharrows, not a vehicle + bike lane. Thoughts?

[scoot]

@chris_s 124343 wrote:

In a typical row of parked cars, 10′ is a safe assumption for how far an open car door will protrude from the curb. Typical parking lanes in Arlington are 7 to 8′ so the whole 5′ isn’t door-zone, but the majority of it is.

One assumption I find questionable in that study: tires of parked vehicles will be six inches from the curb. I believe the law in Virginia is that you must be within 18 inches. But a lot of folks can’t even seem to manage that. Is this ever enforced?

@chris_s 124343 wrote:

A lot of people will ride bike lanes, even door-zone bike lanes much more happily than they will sharrows. Does the increased safety that comes from the increase in # of cyclists negate the decreased safety of having folks riding in the door zone?

This is a great question. IMO, it’s an education problem though. Many people greatly overestimate the dangers of sharing low-speed roads with motor vehicles, yet they are unafraid of car doors (and possibly don’t even realize this is a risk). How many people feel perfectly safe on our highways but are afraid to fly anywhere (while statistics show they are much safer in the air)? I can’t count the number of times I’ve cringed seeing people riding much too close to parked cars.

[dasgeh]

My original thoughts on the issue:

I don’t think car doors are 5′ wide. I would say the 2-3′ adjacent to parked cars is useless. Bikes are 2-3′ wide. VA law requires 3′ to pass, but also allows cars passing bikes to cross into other lanes when safe.

But you’ve hit on my problem will painted bike lanes — it seems to me that there needs to be at least 7′ between the edge of a parked car (i.e. the edge of its mirror) and the edge of a moving car. While in theory cars can cross the line to pass, in reality, many don’t, and instead violate the 3′ passing law. In my experience, I am passed closely more often when I’m in a bike lane, and I can see how uneducated drivers think “but as long as I’m in my lane and they’re in theirs, we’re fine”. They are wrong, but I believe it is common thinking. And unfortunately, neither the Police nor the County is doing anything about it. *sigh*

Plus, I don’t think painted bike lanes convince many “new” riders that it’s safe to bike. So I have a hard time spending lots of capital fighting for painted bike lanes.

I should add that painted bike lanes beside a curb (i.e. not parked cars) are better. But if someone rides 1′ from the curb, and their bike is 2′ wide, that only leaves 2′ of bike lane. If the law is 3′, doesn’t it seem wrong to build infrastructure that implies it’s ok for a car to pass a bike if it’s in its lane?

@scoot 124353 wrote:

One assumption I find questionable in that study: tires of parked vehicles will be six inches from the curb. I believe the law in Virginia is that you must be within 18 inches. But a lot of folks can’t even seem to manage that. Is this ever enforced?

I will say that having painted bike lanes (usually) means the left side of the parking lane is striped, so (theoretically) it should be easier to enforce parking. Of course, has anyone ever seen any tickets in Arlington for a motor vehicle parked partially in the bike lane? Or parked entirely in the bike lane?

@chris_s 124343 wrote:

This is a tough judgement call. A lot of people will ride bike lanes, even door-zone bike lanes much more happily than they will sharrows. Does the increased safety that comes from the increase in # of cyclists negate the decreased safety of having folks riding in the door zone?

Maybe, but my intuition is that if 5% of people bike now, and 60% more would bike, bike lanes might get you another 5%. What we need is to get the 60%… Of course, if you’ve seen studies that show otherwise.

[lordofthemark]

I commute on the Eye Street Bike lanes (SE-SW) in DC, and often ride on the 34th street lanes in Fairlington. I may be deceiving myself, but I think that my ability to scan for people sitting in parked cars, and my general knowledge of when and where a lot of people are likely to be getting out of cars, gives me some ability to judge the likelihood of possible dooring, and I also think that because I ride relatively slowly, I am less likely to be surprised (IE I am less likely to outride my ability to scan) and the consequences in at least some kinds of dooring incidents will be less. As a consequence when I see little traffic in the road I ride on the left edge of the bike lane, when there are no cars parked, I ride on the right edge, when there is a lot of traffic moving relatively quickly in the general travel lane, but there are at least some cars parked I will ride toward the middle of the bike lane. If I note activity in the parked cars – IE people getting out – I will ride more slowly and scan more carefully. If there is a lot of activity, and not much traffic, I will take the lane.

I believe, perhaps naively, that this kind of bike lane usage is different from the modes of riding that in studies leads to high levels of dooring accidents vs hit from behind accidents. So far (kenanehara) I have not had a dooring accident, and not even really any close calls that I can recall.

I note that the complete streets people in Alexandria say that the reason they do so many door zone bike lanes vs bike lanes to the right of parked cars, is, in addition to the loss of parking spaces for visibility at intersections, because of the gutter plate – which counts as part of the parking lane, but not as part of a bike lane. So that a parking protected bike lane necessitates more street real estate than a door zone bike lane does.

[scoot]

@dasgeh 124363 wrote:

If the law is 3′, doesn’t it seem wrong to build infrastructure that implies it’s ok for a car to pass a bike if it’s in its lane?

Are you implying that the existence of painted lines on the road (to set aside space for bikes) gives drivers an excuse to ignore anything that isn’t actually in their lane, and that this might lead to closer passes than would occur if the line were absent? Interesting. Such infrastructure does make me a bit more deferential to passing auto traffic and less confident to claim the full lane when necessary.

@dasgeh 124363 wrote:

has anyone ever seen any tickets in Arlington for a motor vehicle parked partially in the bike lane? Or parked entirely in the bike lane?

Not me. But when I encounter such vehicles, I look for traffic and try to figure out how to safely get around. Checking to see if the offending vehicle has a ticket doesn’t register as a priority!

@lordofthemark,
You are right: the relative probabilities and expected risks for each choice of riding position are a function of both rider velocity and parking turnover rate. I would guess that someone riding slowly is less likely to be doored, less likely to be seriously injured if doored, and more likely to be hit from behind than a faster rider. I find that I am constantly adjusting my riding position depending on these factors.

For instance, on Military Road, I generally take the lane on the downhills but use the bike lanes on the uphills. But even there, I try to adjust my speed in order to stagger conflicts so that I can merge into the vehicle lane when passing a parked car on an uphill. Of course that may not be a great example since there aren’t too many vehicles parked there, so I can sometimes use the parking lane for climbing.

On Clarendon Blvd, I will take the lane all the way from Highland Street down to Rosslyn. Even uphill on Wilson I take the lane in most places. Too much parking turnover, and a lot of people open doors without looking. Those two streets seem like good examples of well-intentioned but effectively useless bicycle-specific facilities.

[TwoWheelsDC]

@scoot 124421 wrote:

Are you implying that the existence of painted lines on the road (to set aside space for bikes) gives drivers an excuse to ignore anything that isn’t actually in their lane, and that this might lead to closer passes than would occur if the line were absent? Interesting. Such infrastructure does make me a bit more deferential to passing auto traffic and less confident to claim the full lane when necessary.

I would agree with this. I think the bike lanes makes a lot of drivers’ mindset go from “I need to move around this person with plenty of room to spare” to “I just need to stay in my lane.” I would try and test that hypothesis using my action cam, but there aren’t a lot of bike lanes or traffic on my commute.

[jrenaut]

I’ve been thinking about this a lot. Taking the kids to school I have two main options – Sherman Ave NW and 11th St N. 11th has bike lanes but the lights are timed badly. Sherman has sharrows. Sherman was completely redone a few years back and I think DDOT likes to parade it around like it was a great road diet success, but what they’ve actually done is made a road that everyone treats like it has a bike lane, but it actually has sharrows. To stay out of the door zone, I have to go far enough into the road that no one can pass me legally. If I take the lane (and I never do), one of two things will happen. I’ll either get stuck in car traffic backups, or someone wanting to do 45 mph will lean on the horn. So I, along with every other cyclist on the road, treat it like it has a bike lane.

I hate sharrows. They’re a constant reminder that motorists don’t know the law and don’t give a crap about my safety.

I don’t know if I have a point here other than “sharrows suck”.

[mstone]

@scoot 124421 wrote:

Are you implying that the existence of painted lines on the road (to set aside space for bikes) gives drivers an excuse to ignore anything that isn’t actually in their lane[/quote]

I don’t think that’s because of the lines, and I don’t think they actually need an excuse.

Yesterday I watched a driver on 66 smash into a stopped car hard enough to deploy her airbag–and that was in her lane, right in front of her. Luckily all the people involved were in big steel boxes with squishy parts to dissipate energy.

Self driving cars can’t come soon enough.

[lordofthemark]

@scoot 124421 wrote:

@lordofthemark,
You are right: the relative probabilities and expected risks for each choice of riding position are a function of both rider velocity and parking turnover rate. I would guess that someone riding slowly is less likely to be doored, less likely to be seriously injured if doored, and more likely to be hit from behind than a faster rider. I find that I am constantly adjusting my riding position depending on these factors.

For instance, on Military Road, I generally take the lane on the downhills but use the bike lanes on the uphills. But even there, I try to adjust my speed in order to stagger conflicts so that I can merge into the vehicle lane when passing a parked car on an uphill. Of course that may not be a great example since there aren’t too many vehicles parked there, so I can sometimes use the parking lane for climbing.

From the policy POV, that makes a good case for bike lanes on uphills only – climbing lanes – while leaving only sharrows on the downhill. At least in places where there is only room for one bike lane on a two way road, that is generally the choice made these days.

On Clarendon Blvd, I will take the lane all the way from Highland Street down to Rosslyn. Even uphill on Wilson I take the lane in most places. Too much parking turnover, and a lot of people open doors without looking. Those two streets seem like good examples of well-intentioned but effectively useless bicycle-specific facilities.

It has been a while since I have ridden there, and I was less confident then, so I rode the lane while remaining hypervigilant for door opening. Today I guess I would either ride the left edge of the bike lane or take the lane. Or simply look for an alternate route.

[Steve O]

@scoot 124421 wrote:

On Clarendon Blvd, I will take the lane all the way from Highland Street down to Rosslyn.

I generally stay in the buffered lane in the Clarendon/Courthouse area; that usually feels like plenty of space, but I definitely take the lane on the cannonball.

Time of day makes a difference there, too. Morning commute time has a lot less pedestrian activity and people parking, getting in and out of cars, etc. Evening is a whole different dynamic along there.

[scoot]

@jrenaut 124427 wrote:

Sherman Ave NW … has sharrows … I, along with every other cyclist on the road, treat it like it has a bike lane.

I hate sharrows. They’re a constant reminder that motorists don’t know the law and don’t give a crap about my safety.

I don’t know if I have a point here other than “sharrows suck”.

I don’t follow. Perhaps your beef with the design is simply about the road width itself rather than the choice of painting sharrows vs. bike lanes? If, in order to stay out of the door zone, you have to ride far enough left to prevent legal passing in the lane, it sounds like sharrows are the better design choice.

OTOH, if people are trying to drive 45MPH, the road could use traffic calming (speed humps, islands in the middle of intersections).

[scoot]

@Steve O 124447 wrote:

I generally stay in the buffered lane in the Clarendon/Courthouse area; that usually feels like plenty of space, but I definitely take the lane on the cannonball.

Time of day makes a difference there, too. Morning commute time has a lot less pedestrian activity and people parking, getting in and out of cars, etc. Evening is a whole different dynamic along there.

Yes, this is probably a time of day phenomenon. I don’t commute through there. My experience with Clarendon Blvd is mostly afternoons and evenings, when there is a lot of parking turnover and there’s a standing vehicle impeding the buffered bike lane roughly every block or two. Plus at that hour there isn’t much eastbound thru traffic: many of the vehicles are only on the road for a few blocks at a time. So I often pass more vehicles (slow-moving drivers probably looking for parking or their destinations) than there are vehicles passing me.

[jrenaut]

@scoot 124448 wrote:

If, in order to stay out of the door zone, you have to ride far enough left to prevent legal passing in the lane, it sounds like sharrows are the better design choice.

I don’t think sharrows are EVER the right design choice. They have no legal distinction – they’re simply a reminder that cyclists have a right to be in the road, too. They’re insulting, like the beg buttons at crosswalks. They’re a reminder that drivers don’t know or follow the law.

[TwoWheelsDC]

@jrenaut 124457 wrote:

I don’t think sharrows are EVER the right design choice. They have no legal distinction – they’re simply a reminder that cyclists have a right to be in the road, too. They’re insulting, like the beg buttons at crosswalks. They’re a reminder that drivers don’t know or follow the law.

And basically the most backhanded accommodation of cyclists by municipalities…”you cyclists are such a high priority, we spray-painted your picture all over the roads…we don’t even do that for cars!”

[vvill]

I think at some point 3-6 months ago I came to the realization that a lot of bike infrastructure (perhaps even the majority) is there to make it appear safer for biking and to increase the number of riders, thus making it safer. Sharrows, painted non-protected bike lanes and those horrid “bikes may use full lane” signs all fall under this. Try riding downhill (eastbound) on Lee Hwy within a few hours of rush hour in the bike lane, or using sharrows on single lane uphill 35mph roads. Changes in driver education and legislation (that protects rather than marginalizes riders) would ultimately help more than all that stuff but small hollow victories are better than nothing, right?

My favourite piece of stepped signage was the “bikes may use full lane” on Lorcom Lane just before Spout Run, followed about 20 yards later by a Bicycles Prohibited sign (meaning on Spout Run, but posted on Lorcom Lane still). Not sure if it’s still like that.

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