• Getting to Green

    An administrator pushes, on a shoestring budget, to move his university and the world toward a more sustainable equilibrium.


Sustaining biking

Bicycle selection as a metaphor for sustainability in general.

June 6, 2013

It looks like Greenback U's bike-sharing initiative has a good chance of going forward.  As mentioned earlier, it's a dual initiative -- long-term assignment of specific bikes to specific riders, plus a pool of more generic bikes for short-term rental.  It's the bikes for short-term use that have me thinking.

It would be good if all our short-term rental bikes were more or less the same with the possible exception of size.  Kind of like Southwest Airlines when they started -- all the planes were Boeing 737's, although some of them were a bit longer and had a few more seats.  Standardizing on one relatively proven (hence, relatively reliable) model simplifies operation, simplifies maintenance, makes it easier to stock all necessary parts in all necessary locations.  It also helps the organization (and its employees) scale the learning curve rapidly, because each learning experience is easily generalized.

So when (if) Greenback's bike-share ("Greenbike"?) gets really big, we'll garner significant benefits from standardization.  But we're not likely to start really big.  In fact, we're not going to start even moderately big.  Unlike NYC's recently introduced CitiBike program, we're going to start small -- really small -- and learn as we grow.  We'll make mistakes, but we want to make those mistakes on a small enough scale that we can afford to pay the price.

Still, it would be beneficial to select the right model of rental bicycle right from the start so that at some point down the road we don't have two (old and new standard) types of bike in our short-term fleet.  And unlike the situation that Southwest faced, the bike market has LOTS of different manufacturers (not just 2 or 3), LOTS of different models (not just a couple of dozen) and NO de facto short-haul standard in the marketplace (Boeing had sold LOTS and LOTS of 737's even before Southwest was a twinkle in Herb Kelleher's eye).  So without endorsing a specific make or model (which I'm certainly not ready to do, even off the record), it's useful to think about the characteristics that will make a bike model a good choice in terms of sustainability.  In fact, that discussion might serve as a model for making good sustainability choices more generally.

One thing's clear -- biking sustainability isn't achieved by focusing on operational energy efficiency.  Energy efficiency (the most transportation out for the least energy in) is a characteristic of the bikes used on the Tour de France, but Tour de France riders have crews of mechanics who travel along with them and work through each night to assure the the bicycle is perfectly tuned each morning.  These are finely-bred, finely-honed exemplars of energy efficiency, if you don't factor in (as Tour rules don't) the energy necessary to transport and sustain all the support staff.  Support (maintenance and repair, as necessary) is a major factor in real life, even if it's considered an externality in top-tier bicycle racing.

Another fact is that bike-sharing sustainability isn't about maximizing the information available to bike-share system managers in the hope that they will be able to come up with the ultimately efficient allocation algorithm -- making sure that just the right number of bikes is available in just the right place at just the right time, so that waste is eliminated and virtue can triumph.  Systemic efficiency is a good thing, but information has its costs and those costs are overwhelmed by benefits only at a scale of operation far greater than Greenbike (I'm starting to like that name) can ever hope to attain.

So if sustainable biking isn't about efficiency in terms of vehicle operation or system management, what is it about?  My take is that it's about durability.  Reliability.  Effectiveness.  The system, as each bike in it, doesn't need to operate at some abstractly defined level of efficiency, but it does need to operate.  First time.  Every time.  And that's going to happen only if we're willing to make some nominal efficiency trade-offs.

One specific example -- our pool of rental bikes can't be single-speed (the Backboro area is somewhat hilly, and not all our students are in top physical condition), but the common derailleur design for bikes with 10, 12, 15 or more gear ratios isn't sufficiently durable.  It's too prone to misalignment and having the chain pop off the sprocket, particularly in the hands (feet?) of a less-than-expert rider.  Instead, a sustainable rental bike should have its transmission housed safely within the hub of the rear wheel.  Which isn't to say that enclosed-hub bike transmissions can't get out of whack, but they're far less likely to do so than derailleur designs.  Necessary trade-offs include accepting a bit more weight and settling for a smaller number of gears (both resulting in decreased operational efficiency).  So be it.

Another example might be use of internal drum brakes, rather than the caliper brakes often seen on expensive bicycles.  Again, it's a question of trading light weight for durability.

Shaft-drive, rather than chain drive -- same deal.

Adjustable seat (saddle) height, but a seat that's not easily removed from the bike frame.  Greenback students aren't likely to be enticed to ride a bike with no seat, and there's nothing either efficient or sustainable about a bicycle that no one's willing to ride.

Simple, durable design that can be relied upon to deliver utility day in and day out -- that seems like the watchword for sustainable biking in service of a wide and unsophisticated audience.  It might also be a model for a wide range of sustainable systems, if and when a time comes that we're willing to think about whole systems (markets and market players/institutions and campuses as a whole, rather than the energy efficiency of a specific building or even a specific light fixture).  Too often, a focus on efficiency uber alles leads to complex and information-intensive designs.  Complex systems have lots of moving parts (like a Tour de France competitor's bike) and are subject to malfunction if even one of those parts goes south (ditto).  Maybe true sustainability, like true elegance in design, is achieved by focusing on simplicity at the macro level.


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