I’m writing this from a plane en route to Berkeley for what should be an awesome conference: Adaptive Metropolis: User Generated Urbanism.  Among the organizers is my favorite DIY city-making collective: ReBar.

Back in 2005, ReBar did something amazing.  They pulled up to a San Francisco parking space and put in a few quarters.  But instead of parking a car there, they rolled out sod, set up a park bench, and created a tiny, temporary public park.  They called it Park(ing).  Check it out:

The point, of course, is that charging cars $1 or $2 / hr to be there is a pretty lousy use of public space.  And that becomes really obvious when we experiment with using that space for other, more awesome things.

That stunt, and the video about it, ended up sparking something of a mini movement.  Later that year, there was an entire day in SF devoted to Park(ing).  After that, more cities joined in.  Back at OpenPlans, we helped organize NYC’s Park(ing) days in 2008 and 2009.  In 2011 (the last year for which they kept stats, since it got so big), Park(ing) Day was celebrated at 975 mini-parks, in 162 cities, in 35 countries, on 6 continents.  

Beyond all that, the city of San Francisco now has an official “Parklet” program, which facilitates the citizen-led transformation of under-utilized public spaces into mini-parks, including this nifty Parklet-o-matic infographic:

This is “user-generated urbanism” at its best.  And I would encourage everyone to take part in next year’s Park(ing) day, wherever you are (unfortunately, you’ll have to wait a whole year until Sept 2014).  But the really interesting thing to note is the way the city (eventually) embraced this, and made space for it in their policies.

Back to 2007: at the same time, NYC was experimenting with “hacking public spaces”.  That year, they began a massive program to do low cost experiments in public space transformation.  The first one simply painted over an empty parking lot in DUMBO.  Over the next few years, major street redesigns in Times Square, Madison Square, Union Square, the Meatpacking District, and elsewhere all over the city were started with paint and planters, not with jackhammers and concrete.

By doing these projects at super low cost, with cheap (but nice enough) materials, and by leaving the option open to change their minds if things didn’t work out, NYC DOT unleashed a torrent of public space innovation across the city.  I’m not sure any established city has ever seen the level of micro-scale street redesign that NYC saw from 2007-2012.  And the process of doing low-cost experiments, then collecting data and iterating was a breath of fresh air.

That’s what you might call “agile urbanism”.

So, we’ve got “user-generated urbanism” and “agile urbanism”.  That sounds a lot like how we describe the evolution of the internet and the software development process, respectively.  It might just be my internet centrism showing through, but it makes sense to me, and I see it continuing.

Now, in 2013, we’re seeing a new trend in our cities, which we might call “peer to peer urbanism”.  

Web- and mobile-enabled peer networks are bringing “web 2.0” models of collaboration and commerce (think: Ebay and everything that followed) to every part of the city.  You can now share or rent your apartment, your car, a seat in your car, your stuff, or even your dog.  You can also crowd-fund public works projects, shop at virtual farmers’ markets, and start to count on new forms of peer-to-peer humanitarian aid.

This latest wave has caused more than its share of problems as cities grapple with the implications of the rapid expansion of peer-to-peer everything.  It challenges fundamental notions of professionalism and trust, the same way Ebay did in 2001.  For example, if I use SideCar and give someone a ride, am I a taxi driver? (the state of California just decided I’m not, but it took a while to figure that out).  Does renting out my apartment on Airbnb turn it into a hotel? (New York state thinks it does).

As this continues, we have an opportunity to re-think how we regulate city activities for the public interest.  I think the big opportunity is to harness the data streaming out of all of these activities and use it to enable a more permissive, but more accountable, “2.0” regulatory regime.

So, anyway, maybe this is what we mean by the adaptive metropolis.  The city that changes, changes fast, and keeps on changing in response to that change.  Change is good.