Degrees of Bike Lane Separation pt. 1

Practicing their riding skills at Copenhagen's kids bicycle learning playground on our last trip. 
Note the kid-scale protected bikeways, etc. There's also a separate toddler area.

I want to talk a little bit about protected bikeway design. San Francisco, like a few other American cities, is moving forward with its efforts to build more protected bikeways. I spent years of my life on that effort as the Deputy Director of the San Francisco Bicycle Coalition. I'll skip all the politics and personalities of why that work was so difficult, because the good news is that the City is building more protected bikeways, and it's finally time to talk more about design details. 

Design nuances have, of course, always been a part of the conversation. However, they were historically the least complicated or heated part of the conversation, the part brushed to the very end when everyone was too exhausted to fight much more, and the options seemingly too limited by virtue of the fact that there was no guide. Not surprisingly, once the NACTO Urban Bikeway guide came onto the scene, that document became the standard for most design choices. Fast forward a bunch of years of complicated politics and design application experience and now we're finally at a point when we can take more space to talk about design.

So, today, let's talk about lane width.

My brother and his family live outside of Copenhagen, Denmark, so I've spent some time over there visiting, commuting by bike with my own family. First, by cargo bike and bike seat when they were tiny. Then, with my kids on their own bikes, albeit at very delicate learning ages--newly physically capable but mentally in development. On our last trip, my eldest was about to turn eight, and my youngest five. Both knew how to ride bikes. My eldest was already used to riding to school on his own bike some days. My youngest was a champ at riding her bike in Golden Gate Park on car-free days. So they were tender, tender little ducklings. That said, these are the ages when kids in Copenhagen also start to commute on their own bikes, so they were hardly unusual in that respect. We were extraordinarily ordinary in that city. Painfully, dully run of the mill. No one looked twice at us.

So, here's the thing about new riders: they fall. Let me repeat that: no matter how careful you are or how closely you watch them, at some point, they will likely fall. Same as when they're playing at a very, very safe playground or at school. In fact, my son fell on his bike three times while we were in Copenhagen on our last trip. Once on the first day (thanks to jet lag), once when we were riding up the coast to the beach and he wanted to splash through a puddle that was actually a trench and once when he didn't notice a wooden post in the middle of a greenway path, because well, I really don't know why. It was really big.

The trick, of course, is to ensure that kids, and anyone else who might be having a funky day or a momentary lapse of judgment, can fall and still be safe. Specifically, that they will not be run over and treated as an acceptable casualty of car culture. I've also fallen as an adult--twice--on my bike. Both at intersections and at a stop. The first I blame on a particularly poor shoe choice; wooden-soled clogs are not your friend, no matter how much you like their clack. The second on a bad brake job by a bike shop that shall go unnamed. Similarly, my husband's basket once came unmoored out of the blue and he went flying off his bike on the lakefront greenway in Chicago. He was also taken down once by black ice in Manhattan, also on a greenway.

So, people fall. Shoes and baskets get persnickety, minds wander to dinner and the possibility of video game time at home. Our infrastructure should support this, just as we build shoulders on highways and curbs on sidewalks. Or squishy mats on our playgrounds, and non-slip surfaces near our pools. Yellow caution dots on subway platforms. Kneeling buses. Railings along stairs. Etc.

How do you design for falling? I'm going to look at seven examples of raised bike lane width in Copenhagen, going from not so great yet, to excellent examples of forgiving designs.

Too Narrow

Jagtvej runs through some of my favorite parts of Copenhagen, and much of it is perfectly fine. But there's an especially narrow section along Assistens Kirkegård, a beautiful urban cemetery home to Kierkegaard's grave, that is less ideal. In that section, you are forced to bike close to fairly high-speed cars and large city buses. In addition, despite what this Google Street image suggests, whenever I've been there, this bikeway has been extremely crowded, so you also have people on regular and cargo bikes trying to pass you at speed. In short, Jagtvej has no shy zone and no fall zone. I never let my youngest kid ride on this bikeway, and whenever I had my then-almost-eight-year-old with me, there was a lot of me yelling at him to stay right and to ride straight and him getting flustered. He got dinged at a lot with impatient bells. Harsh words were spoken in Danish.

The width on this bikeway is quite similar to the Masonic bikeway in San Francisco.

G.I. Kongevej runs through Fredriksburg, which is a small municipality more or less within Copenhagen. It's a lovely shopping street and residential area, but the bikeway is narrow like Jagtvej. In general, the narrower bikeways in the Copenhagen area are on the smaller neighborhood commercial streets, which makes sense. That said, the traffic speed on this street is slower, and there are fewer large vehicles speeding by, so it felt better than Jagtvej with my older kid on his own bike. There are also sections that dip behind bike and car parking areas, which creates some feeling of intermittent relaxation. So all in all, it was a slightly more comfortable place to commute with my older kid. That said, if this were on a hill, it would NOT be comfortable for riding with an independent kid.

The width on this bikeway is quite similar to the more generous sections of the Masonic bikeway.

Kalkbrænderihavensgade has very narrow bikeways on two sides of a huge street with speeding cars and huge trucks. It runs along the waterfront and connects to the street that gets you into one of the remaining industrial waterfront areas of the city, which also happens to have the international school. My kids went to camp at the school for two weeks the last time we were there, so we experimented with different routes, including Kalbrænderihavensgade. Of all the streets we experienced, this was hands down the worst for riding with kids. It was a wind tunnel and there's a turn into the industrial area where you can see the enormous truck wheels rubbing the blue of the bikeway crossing paint invisible. The truck wheels were taller than my daughter and barely a foot away whenever we made that turn. And lest you assume we must have been totally out of our minds for letting our kid bike this route, we were surrounded by other families heading the same direction.

My youngest kid was so proud of herself to ride the mile to camp on her own bike, but it came at the price of me and my husband shadowing her very, very closely (e.g., touching), and a lot of paranoia and fear. This bikeway does not work when it comes to shy zone, fall zone and just general comfort. Have I mentioned it's also very loud? Also, that people wanted to pass on their own cargo and solo bikes? It's too many stressors at once.

This bikeway is similar to the Cesar Chavez and Potrero protected lanes in San Francisco.


Østerbrogade has two busy raised bikeways on either side of a large neighborhood commercial street. The block pictured is actually the place where my son fell for the first time. My heart stopped when he went down; I think he hit his front wheel on the sidewalk curb. He was fine, if a little dazed, but it was only because this bikeway is just wide enough to give him space to fall without interacting with any cars or create a huge pile-up of people on bikes. In fact, another woman stopped to help us, and everyone was very nice and surprised about the whole thing. This bikeway is in a family-dense neighborhood, and gets very busy. I suspect that they'll need to widen it soon to accommodate the crowds. But for now, it's just okay enough, and I am eternally grateful for that fact.

Ellebjergvej is a highway running through the town of Valby and some of the other western suburbs of Copenhagen. It is a horrible street as a place, but it gets you to the excellent Valby pool as well as a large park and the equivalent to Home Depot. One of the train lines runs just on the other side of the street. It's loud and the street is super fast. So, all in all, probably one of the least likely streets to put on a good bikeway design list. BUT the design of the bikeway works for this context, and I appreciate the heck out of that fact; we spent a lot of time at that pool. The bike lane is extra wide, there's an additional planted buffer and there's even (one) tree. I kept my son close when we were near curb cuts to the gas station, etc, but otherwise it was okay to let him range slightly ahead. If you have to have streets/highways like this in urban areas, this is the minimum you need to make the bikeway viable for independent kid riders and other more tentative riders.

I'm struggling to think of an equivalent lane in San Francisco. The path along Marina Boulevard comes closest, except it's two-way, multi-use and there's no buffer.


Nørrebrogade is, like Østerbrogade, a medium-sized neighborhood commercial street that connects to the downtown. This section has extra wide bikeways on both sides, which are part of a street redesign project that got a lot of press a number of years back. Part of the street was also made car-free so that buses could have priority. The result is a blooming street with tons of lively shops, people chatting on the street and a very busy but very manageable bikeway with a young solo rider. I think I'd struggle to have both kids with me at the same time on their own bikes on this bikeway at the ages they were last time we were in Copenhagen. But with just one solo and the other on my bike, I'd feel fine. Now that they're a bit older and streetwise, I think it would be fine to have them both on their own bikes, too. 

The one block of Valencia between Duncan and Cesar Chavez is the closest equivalent to this bikeway in San Francisco.

The seafront path in the Northern Suburbs is a long continuous stretch of not much. It can be very relaxing, and takes you out to beaches and ice cream in the summer, and--I suppose--bleak, moody views in the winter. This is one of the few places in the Copenhagen area where you see exercise bicyclists pounding it out. It's also one of the first places where I saw my brother let his oldest, tween daughter ride way ahead of us without any worries; she commutes herself around their suburb on the regular. I did a double-take the first time because it seemed like SUCH A WILD IDEA--children, being free and independent! What's that?! But she did, and it was fine, and my kids immediately got jealous and asked for more ice cream. This path grows out of a relatively narrow bikeway (actually a continuation of Østerbrogade) similar to G.I. Kongevej that runs through Hellerup and some of the other tonier suburbs. But then once you get into the area with all the parks and the proper waterfront, it opens up and becomes wide and pleasant. There is a surprisingly little car traffic, but what there is speeds by. I especially appreciate that the designers made the bikeway almost absurdly wide in the places where there's "extra" roadway width, rather than leaving it in the car travel lane or trying to cross-hatch it out with paint and idle wishes, as we tend to do here in the U.S.

Sadly, there is no equivalent to this in San Francisco--yet.


On the whole, raised bikeways are not the best design choice for San Francisco streets. Concrete buffers clearly work much better for two reasons. First, our local drivers need very unsubtle language to understand where and where not to drive and park, after decades of the City telling them otherwise. Second, we've let traffic volumes, vehicles size and speeds get so big that everyone else needs as much armor as they can get--have you seen the new pickup trucks people are buying like candy? But if we're going to do raised bikeways in the future, I strongly recommend that city designers not skim over the "recommended" section of the NACTO guide, but give attention to the following:
  • What happens when someone falls on this bikeway? Will they die or be grievously injured?
  • Is there enough room for error when it rains?
  • Is there enough room for error if you're a 40-pound kid and it's really windy out?
  • Can you ride two abreast with a wiggling kid and still let other people pass safely?
  • If it's dark, will it be clear where the curbs are, if you are not the most careful person young person yet, or someone with a learning disability that causes inattention? What happens if you don't see them?
  • Etc.
The higher the motorized vehicle speed = more space
The bigger the motorized vehicles = more space
Hill = more space
Wind or other natural impediments = more space
Crappy pavement = more space
School or park route = more space
Everywhere = protected intersections

Of course, all this assumes that you are designing bikeways from the perspective of people biking--current as well as future, potential riders--and not as an afterthought to be cobbled together from the bitter cast-offs of people who refuse to share or face the reality of what is happening on our planet. Or in reaction to blood spilled on your existing substandard designs. I'll leave it at that. 

Instead, I'll just reiterate that I hope that NACTO gets far more serious about updating these sorts of considerations in their future bikeway guides in much finer grain detail. We've made progress, but there are miles to go and much learning to do, and we're in a dead sprint before the consequences of years of inaction catch up to us all.