U.S. Awareness of Protected Bike Lanes Is Literally Growing Exponentially

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Michael Andersen blogs for The Green Lane Project, a PeopleForBikes program that helps U.S. cities build better bike lanes to create low-stress streets.

As people in the protected bike lane movement start to get a handle on 2015, it’s worth pausing to look at the magnitude of 2014’s success.

If any one chart can tell the story best, it’s probably this one.

There’s a word for that sort of growth: exponential.

In fact, we can even put a formula on it: approximately 38 percent growth every year since 2006, almost like clockwork.

Buried inside this trend is another one that shows how our language is changing. Last year was the year when most professionals settled on the phrase “protected bike lane” as the best way to describe these designs to a general audience.

What these charts are attempting to track, of course, is the spread not of a type of infrastructure itself, but of something more powerful: the idea of a type of infrastructure, as shown by the number of times it comes up in the media.

But newspapers are an ever-smaller share of the media. So let’s look at a broader measure that includes not only U.S. newspapers but also English-language websites, magazines and newsletters from around the world.

Yep. There’s something happening here.

Change is happening on the ground too, of course, though the sample size is smaller and progress has been less consistent.

Here it’s possible to tell a very specific story about what happened. Protected lane projects started to gather steam in Bloomberg-era New York City, got a big boost from Chicago in the first year of the Emanuel administration (2011-2012), then saw a lull in 2013 as those two cities finished off the low-hanging fruit and started tackling more difficult streets. Meanwhile, the country’s less executive-focused cities caught up. Last year saw another spike in building as cities across the country installed their first, second, or third such projects.

Because that’s exactly the way a good idea spreads: a lone innovator starts doing something. If it works, a few thought-leaders notice and follow suit. Then more and more people notice, and finally the idea reaches a tipping point and becomes mainstream, routine and, finally, boring.

As we head into 2015, protected bike lanes are sitting on that cusp. Here’s to a boring 2020.

Source on all media charts: Lexis-Nexis. Source on project chart: Green Lane Project’s protected bike lane inventory.

You can follow The Green Lane Project on Twitter or Facebook or sign up for its weekly news digest about protected bike lanes.

12 thoughts on U.S. Awareness of Protected Bike Lanes Is Literally Growing Exponentially

  1. This is nice to hear. And yes, our language is changing, but it’s bad enough when people flippantly and needlessly use the word “literally” in conversation or written prose. But in a title? It is just as meaningful (and correct) to say “U.S. Awareness of Protected Bike Lanes Is Growing Exponentially”

  2. Or maybe we could stop using “exponential” when we mean “significant” or “doubling”? Not sure on this, but doesn’t exponential refer to a number raised to a power, usually of at least 2? Thus, if you had 3 article mentions in one year, the 2nd year would have something closer to 9 mentions, and the third year 81, etc? My spouse will shake her mathematician’s head at my brain cramp, but I think that’s what exponential growth means, and I think it’s a much abused term.

  3. I agree. Exponential seems to be used as a synonym for fast, but it would be perfectly reasonable for fast growth to be linear, which is sort of implied by the statement that awareness has been growing at the constant rate of 38% a year. Exponential growth would mean that it is increasing (or decreasing) at a rate proportional to the time.

  4. In an article about a concept very recently believed to be impossible in the US (“something so exotic and European will never work here!”) I’ll take it as a portent of its upcoming full-on mainstreamed status that the biggest criticism to the article so far is a prescriptivist note about a changing usage in language 😀

  5. Btw,



    Living languages change over time. The Old English forebear of “silly” meant “blessed,” but gradually acquired a new meaning over time. Similarly, in Old English people spoke of the “brid” perched on the tree. Over time some speakers metathesized a couple sounds to arrive at “bird,” and the latter eventually won out. Native English “eyren” was gradually replaced in the Middle-English-to-Early-Modern-English period by the loanword “eggs,” from Old Norse. I’m sure some English grandmother of yore berated her grandchildren for defacing the language speaking of “bird eggs” instead of “brid eyren,” but English soldiers on today.

    Chill out, English will be fine. 🙂

    Speaking of linguistics and getting back on topic, I find the linguistic variety surrounding protected bike lanes/cycletracks/bikeways/etc. fascinating (I believe the PeopleForBikes postings prioritize “protected bike lanes” as they bring about the most positive sentiment among people new to the stuff). As with previous innovations, various neologisms currently exist–as the concept spreads into reality in more and more people’s lives and people make it their own it’ll be fun to see what we end up calling all this stuff.

  6. Yes, this is why I put “literally” in the headline – because it pisses me off when people say “exponential growth” but just mean “rapid growth.”

    Generally speaking, growth is exponential when it keeps increasing every year by the same percentage. Doesn’t matter what that percentage is; the important thing is that every year builds further on the progress of the previous one.

    To me, what this means is that this idea is having babies.

  7. Another way to think of “exponential” is that over time, the growth will “compound.” Every year, the total annual increase should be bigger than the increase of the previous year.

    Snowballs that turn into avalanches are exponential. The stock market is exponential (at least over a long period of time). Your IRA is exponential. The spread of the flu is exponential at the beginning of each year. Human population growth has been exponential. Facebook membership was exponential for the first few years. Computer processing power has been exponential.

    The bad news: exponential growth usually ends quite abruptly. Like a parachuter jumping from a plan and hitting terminal velocity, his pull-cord, or the ground. But with ridership at just 1-6% in our major U.S. cities, there’s still lots of upside for growth in bicycling. So maybe we should invest in a bike company that has the next generation of the urban bicycling market figured out?

  8. The article is about how “protected bike lanes” as a phrase s being used more and more in online and print media. Michael Andersen used the word “literally” was quite cleverly and correctly in the headline.

  9. I believe the protected bike lanes will be the most likely way to improve cyclists’ numbers in the U.S. I know this has been debated a million times and in a million different ways, but people are quite simply afraid to bike on lanes right next to massive SUVs and trucks. I am not especially fearful but, now that we have small children in our family, I think twice about conditions before riding on the road. Although I would like to ride to the grocery, if conditions aren’t really good, I don’t want to be roadkill and leave behind toddlers.

  10. Constant gain of 38% per year is exponential. Constant gain of 100 (or whatever) extra mentions per year is linear.

  11. I’m more interested in the number of publications using the terms, not how often they are used. Having one media outlet using the same term more times doesn’t mean there are more people people aware of the term, it just means the same readers saw the term more times.

    Show me a chart in the number of publications that referenced “protected bike lanes” year on year and then see if it supports your hypothesis that more in the us are aware of protected bike lanes.

  12. He didn’t say that more people are becoming aware. He said that the number of protected bike lanes is increasing as the term becomes more used and familiar. In other words, as we integrate “protected bike lanes” into the lexicon, cities are building more of them. Or perhaps because more cities are building them, the term has become more integrated.

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