Creepy

Is it just me who finds the new Toyota Prius ads creepy? Apparently.

Yes, I know that the Prius is the most fuel-efficient car out there. Yes, I know the Munchkin-like seething mass of humanity is mostly computer-augmented, just like the Coliseum crowd effects that won the Oscar for the movie Gladiator. But it still creeps me out.

Part of what I know about the Prius is this: It's a car. (well, duh.) And that means it's big and heavy (relative to my scrawny transporation system, that is.) Think about it this way: A Prius hauling a single person (most of them do) is getting (let's say) 50 person-miles per gallon of gas, (which contains 31,548 kcal), or 31,548 / 50 = 630 kcal per mile. On a bike, I can cover roughly 15 miles per hour burning 700 kcal, which works out to 700 / 15 = 46.7 kcal per mile. So my system (for a single passenger) is 13.5 times as efficient as a Prius. So if a Prius gets 50 mpg, I get "675 mpg". (I know that's a bit of a red herring.)

In honor of this ratio, I'vc created a graphic. You can download the high-rez version here, if you want to put it on a t-shirt or something.

But the latest data point about hybrids is a truly unexpected one: according to insurance statistics, hybrid drivers drive more, get more tickets, and have more accidents than non-hybrid drivers. (Perhaps they are distracted by their hypermiling techniques?) According to the study cited here, the decreased guilt associated with improved fuel-efficiency increases the number of discretionary trips by up to 25%, largely offsetting any petroleum savings.

It is, after all, just a car.

Hardware, Software, Wetware

My twin brother Willie (who runs teams of engineers that design highly-sophisticated silicon chips) used to say that there were three kinds of computer "ware": hardware, software, and wetware. Hardware and software (and their distant cousin, firmware) you already know about, if you're using the Web to read this. Wetware is, of course, the user of the computer, and ultimately where the rubber meets the road, so to speak.

It seems to me that when one thinks about bicycle-commuting systems, the same three levels impose themselves. Let's consider them in reverse order:

There's the "wetware" crowd, the people who get out there and "just do it". Sometimes referred to as "vehicular cyclists", they insist that all that they need is the road and the rules for it, which exist everywhere. They tend to be skeptical of structured solutions. The most radical among them can be rather vocal in their beliefs that structure is bad, and will give the powers that be the ability to segregate cyclists to a second-class status. (I count myself in this crowd, although to be sure not one of the radical ones.)

Then there's the "software" crowd, the ones who think that to be safe, cyclists need the protection of bike lanes and striping -- clear demarcations that differentiate cyclist territory from motorist domain. Sometimes referred to as "infrastructuralists", they don't commute as much as vehicular cyclists, simply because bicycling infrastructure isn't so widespread as it could be. Those among this group who do commute regularly therefore are geographically distinct -- they tend to be located out West, in Oregon, Colorado, and parts of California and Washington. Sort of like rare birds with a distinct habitat.

Finally, there's the "hardware" group -- those who think that to be safe, bicyclists need their own separate and independent bikeways. These can be bike paths (typically engineered for about 8 mph, and leading to recreational destinations, not so great for commuting, really) or fully separate bike lanes (preferably with curbs to physically separate them from cars). The Achilles' heel of these approaches is usually the place where they have to come back to the "standard" roadway system. Rejoining the regular transportation system is the most critical aspect of any separated system, and often times it is under-engineered (the "engineering" consisting of a wheelchair ramp at the curb.)

I have a 3/8 mile stretch of bike path paralleling a busy road that I use on my daily commute, and I have learned that rejoining the traffic from that path is by far the most treacherous part of my daily ride.

Recently, a couple of designers have gone quite a bit further and proposed systems that totally separate bikes from the quotidian automobile infrastructure. (Maybe I should categorize these as "super-hardware" people.) Personally, I find them amusingly naïve and impractical. Naïve, because these people are convinced that public financing can be found for these schemes when it's hard enough to find money and will to do simple striping. Impractical, because I don't see where these structures provide the motiviation to ride. If one is motivated, he or she tends toward the "wetware", and all these other things just become (in their absence) excuses not to ride.

I'm not trying to be mean here, it's just my belief that since the advent of the first commercial "safety bicycle", the bike has evolved into a pretty efficient system which works pretty well quite on its own, thank you very much. When I see a new idea to improve the system, I'll be the first to doff my helmet. but it's not so easy to get excited about ideas that just tinker around the edges.

Anyway, let's take a look at a couple of these visionary pretexts for not riding.

Vel0-City is a system of elevated enclosed tubes proposed for Toronto. To its credit, it seems to have the macro-planning thought out in that it appears to be integrated into the mass transit system as a whole. To be fair to the envisioners of this project, I think that protection from the elements in the winter in Toronto is a winner of an idea, but I wonder if the good taxpayers of Toronto will support yet another mode of mass transit, in addition to its existing bus, tram, and metro lines. Like any of those other mass transitways, I suspect, graffiti would pose an ongoing problem.

Remarkably, Velo-City promises a perpetual tailwind, with one-way tubes somehow creating a "dynamic air circulation loop." I could use some of that, but I wonder about the physics!

The Shweeb (no, I don't know where the name comes from -- it seems vaguely German in its tendency to clear the throat) is a pedal powered monorail that exists as an amusement park ride in Roterua, New Zealand. Two pedal-powered capsules swing around a 200M monorail racetrack. Frankly, this looks like quite a bit of fun. The fun rumor is that someone in the London Development Agency has latched on to this idea as a means of mass transit in London. (Don't you just love the "science-fiction pulp magazine cover" look of the rendering at right?) I think this idea works much better as an amusement park race than as a mass-transit system. I'd hate to get stuck behind the little old lady who's doing some urban sight-seeing when I'm in a hurry to get to work. And as much maintenance as Velo-City would require in removing graffiti, Shweeb would require in spades. Believe me, you don't want the capsule that's just been given up by the vomiting drunk!

As a postscript, here's a different take on bikes-as-infrastructure: Hybrid-squared. This system proposes a public bike system (think Vélib) whose bikes have a combination of dynamos and regenerative braking to charge ultracapacitors that then dump their stored energy back into the grid when you return the bike to its station. It's a neat gedankenexperiment, and envisions a credit system where bike-commuting pays for mass transit use, which is a clever scheme. But I wonder if the net energy would amount to a hill of beans, enough to ever pay back the investment in infrastructure. (Is anybody running the numbers on these flights of fancy?)

Disc Brakes

... or is it Disk Brakes? Anyway, I've never understood the use of disc brakes on anything other than a mud-eating mountain, downhill, or (maybe) cyclocross bike. The brake-choking mud or dirt seems to me to be a requisite to justify it.

Why is this? The reason is simple, if you have an interest in amateur physics (and I do): Braking Torque. Think of it this way: if the braking is occurring at the hub (as it is with a disk brake), then all the braking force has to be transmitted from the hub, through the spokes, to the rim (where after all, the "rubber meets the road.")

This means that the spokes (which are the weakest link of the wheel) do at least twice as much work on a bike equipped with disk brakes. I haven't seen statistics for this, but I'd be willing to bet that spoke breakage is higher on bicycles equipped with disk brakes. I also wonder if there is a higher rate of failure of the seat stays (which absorb braking force), since the force applied by the disk brake is several times higher than a rim-caliper brake. (see illustration)

On a rim-brake setup, you can think of the entire wheel as the "disk". Braking force is less, but more importantly, the braking force is being applied near the rim, and the only loads that are carried by the spokes are for driving force (which are inevitable) and structural (keeping the wheel true and round).

As long as the wheel is in fact true, and you can properly keep adjusted your rim-caliper brakes (of whatever type), They are a physically and structurally superior solution. It does require that you keep your wheels true, but I'm sorry, if you have wobbly wheels, your riding quality is going to be pretty poor no matter what. I will grant that using the rim for braking means that the rim is eventually going to wear out and you'll have to replace the rim (rebuild the wheel), but we're talking tens of thousands of miles here.

Of course, bike manufacturers are loading up their offerings with disc brakes, even for bikes that will never see off-road use (and of course many so-called "mountain bikes" will always be on a paved trail.) Here's an offering from Raleigh, here's one from Trek, here's a Civia, and even REI has one. These are all touted as premium bikes in their categories. But bear in mind that the disk brakes, while superior in an automotive setting, don't convey that much superiority in a bike that won't be used on unpaved trails.

Give me old-school cantilevers any time. They require some hand strength, but they never fade, and boy are they reliable.

Update: The excellent "Cozy Beehive" blog has a report on a disc brake induced failure here.