Saturday, February 5, 2011

117> Snow Day Musings

Well, we’re having a snow day in Houston…Well not really a snow day, actually it is an ice day. The buses are not running. Everyone is being advised to stay home. At the moment, all of the freeways are closed. It seems like a good moment to curl up with a warm laptop, and tap out some thoughts about this epic winter.

Being a mere six hours from Mexico, we are not well prepared for these kinds of weather events. We have no salt trucks or snowplows, but yesterday a truck preemptively applying a deicing solution caused a great traffic jamb, of which I was a part. It did no good.

It boggles the mind to think of the calamity that these weather systems are causing across the US (and Europe?) this year. In the last one, there were even fatalities in New York because ambulances couldn’t make it through. Enough, already! Is this really the best we can do?

The ongoing recession should serve as a “teachable moment” that illustrates the effects of a few percentage points of reduced economic activity. Clearly, these weather events must work against our collective well-being, event though we may not make the association.  Such shutdowns further compound the wasted productivity caused by simple traffic, illustrated in the chart below.


Being paralyzed like this should point out the consequences of having all of our transportation “eggs in one basket.” For example, the rise of radical Islam makes me wonder if anyone has really considered what would be the effect of a sustained campaign of sabotage against road-based travel in a modern society. After all, a single disabled vehicle can nearly freeze a whole highway. Imagine the effect of terrorists simply targeting the tires of moving vehicles on a continuing basis… or even traffic lights for that matter. (I’m glad my readership is a very small and constructive group, or I would not share such notions)

There is also the warm weather counterpart to the “snow day,” which is street flooding. PRT systems can be specifically designed with this in mind. As ridiculous as it sounds, many urban areas around the world are built on floodplains. What would have been, for example, the result of a PRT system in New Orleans? If predictions of climate scientists are correct, we are in for lots of major weather events of all types in years ahead.

Anyway, my point is that society has reached a point of unprecedented interdependency, and is very vulnerable to any disruption in travel. These are not the days when everyone had canned leftovers from their large gardens and a cord of firewood on hand. If our transportation stops, our means of survival (and escape) does too.

Astute reader Lars Endre recently referred to raised PRT as exploiting “the virgin third dimension.” I love the phrase. It occurs to me, however, that it is not really virgin at all, at least around here. Here we have lots of spaghetti-like highway interchanges that are many stories tall. The interesting thing is that these forays into that third dimension are the very reason this city has drawn to a halt. Raised roadways and overpasses freeze first. We have many miles of raised HOV (High Occupancy Vehicle) lanes, connected to “Park and Ride” parking lots. Our embryonic light rail system continues to work, but nobody can get to the stations.

Too bad we can’t exploit the nice dry undersides that such elevated structures enjoy. Oh wait… We can! Yes, it’s the underside of that virgin third dimension that offers the possibility of completely weatherproof transportation. (You knew I would turn this into a shameless plug for suspended PRT sooner or later, right?) 

While we're talking about snow, although this is a bit off-topic, I would like to take this opportunity to mention the troublesome act of repeatedly salting roads. It reminds me of the age-old notion of dumping waste into the ocean or atmosphere because “It’s just so darn big that it can’t be hurt.” We know better now, but we continue to salt the earth on a mega-industrial scale. (10 million tons per year in the US, which works out to 66 lbs. annually per person) It works its way downward, eventually, to the water table, where it migrates “away.” Some readers may have seen these structures along roadways and not known what they are. They are structures for storing all of that road salt. I only wish PRT could solve this dilemma too.  

Finally I just thought I would share these pics that I happened upon. As you can see, the need to remove snow from our 2D transportation systems is not confined to just roadways.

Well it’s a day later and the sun is shining and the roads are clear once again. Time for me to wrap this up…

PRT cannot mean an end to roads or the costs of maintaining them. There still will be the need to move heavy loads, that last mile problem, and the whole countryside beyond. But an extensive, all-weather PRT network could, in times of crisis, be a very important backup system to have. We sure could have used it yesterday.   


akauppi said...

Enjoy the snow, Dan.

You mentioned ambulances. In India, it's a serious issue that emergency vehicles don't get through because of traffic jams. Sometimes, people don't even give room to them even though they'd have sirens on (I've heard, not seen). This is yet more reason to do something about street level congestion.

On road icing, we started systematically reducing that some 10-15 years ago, for the reasons you mention. It goes like this:
- the timing of when to apply de-icing (actually, a salted liquid) is carefully planned based on weather forecasts and only applied "just in time" when and where actually necessary
- some counties are completely de-icing free, as a test. Drivers are warned of this at the border of such counties. Accident statistics are being gathered and compared - I haven't heard these areas would have any higher rates of accidents because of stopping de-icing. People just need to drive more carefully (or not drive at all in very, very bad circumstances).
- ICT allows information passing directly to cars, either using radio or connected GPS devices. People can be warned of ice formation either via this or via street side electric road signs.
- Some ground water bed areas have been structurally isolated from the roads (expensive rework of the ditches etc.) to prevent street side salt (or i.e. harmful leakages in traffic accidents) from reaching the water bed.

Most of all, it comes from the attitude. Instead of bringing summer-like condition year around (with using excessive salt) we adapt to the weather and drive accordingly. This adaptive attitude is what is required also in other aspects, to reduce our footprint on the environment.

Lars Endre said...

Snow and ice; a real 6 months issue here in Norway. This goes to two design choices at once.

Yes, hang'em up above ground and below the rail structure.

Even if the Posco/Vectus test track in Uppsala (same latitude as Oslo) has shown that it is viable to have "snow plowing" pods on-track/on-rails, any solution that hangs pods underneath the track have solved the snow/ice problem "by design". For a country cut by the the artic circle about half-way up north, it's evident ...

Andrew F said...

Even here in Toronto we had a storm last week (Wednesday) that caused a bit of media panic (usual 'storm of the century' nonsense). It was a quiet day in my office, which is mostly IT. They elected to work from home that day. It turned out to be a non-event, and we had a storm on Saturday that was easily worse but generated no media hysteria.

I suppose it boils down to the fact that wherever you are, there is at least a few days a year that you experience weather beyond what your infrastructure is designed for.

While snow ought not to pose much risk to suspended PRT operations, I can imagine high winds being a concern, since elevated guideways would tend to be more exposed than ground-level roads. The dampener motors will need to be powerful enough to counteract crosswinds, and even then you might end up with a vomit-inducing ride in gusting wind.

I don't doubt that PRT (even ULTra-style systems) would be more reliable than the private automobile in inclement weather.

Dan said...

Akauppi, that’s interesting stuff. The road salt use in the US peaked quite a long time ago as well. This was a pretty unusual situation, something we call “black ice,” where the ice is so clear that it is completely invisible to the drivers. Even with all of the freeways closed, we had almost 800 ice related accidents. Of course Houston drivers have absolutely no clue about how to drive on snow or ice.

Lars, I think the design has advantages far south of you as well. Many cities have structures just above the 100 yr. floodplain, whose properties drain to slightly lower streets. (The streets may flood a few times a year) On flat land, streets are often essentially designed to flood in order to save the structures. Even a slightly elevated station, say 35 cm over sidewalk height, would operate when cars would be dead in the road. Stations could detect water levels and take themselves off-line automatically. Cities, being well aware of their own topography, could design PRT systems accordingly.

Andrew, the swing-arm system is more than dampened. It is actually locked into whatever position it would take just based on vehicle inertia, without load imbalances and wind gusts. Wind should not be a problem, at least until we have projectiles flying through the air. (Although the particular top torque motors in the pic are a bit undersized for severe crosswinds, but I didn’t want to change them since the drawing is to scale and I was in a rush.) BTW, the possibility of swinging from gusts of wind has very serious ramifications in track design…Imagine swinging into a post or passing vehicle! Anyway, I do think that PRT can be weatherproof if designed right.

qt said...


If the swing-arms are "locked," I trust you are considering the possibility of severe wind-gusts causing the pods to exert torque loads on the track and support structure? That's a fair amount of surface area on a pretty long lever-arm...

Also, just as a language-point, I'm not sure I'd want to call ANYTHING "weatherproof." "Weather" is such a big word. Kind of like watching somebody use a military rifle on "bulletproof glass."

"More weatherproof than what we've got now" is quite impressive enough, I think. And I agree PRT has real advantages that way.

akauppi said...

For your viewing pleasure, CNN and Richard Quest checking out Helsinki "snow war" in January this year:

We're not really that good. :)

Andrew F said...


Our winters are not nearly that bad in Toronto in terms of snow accumulation. Montreal uses many of the same tactics, however (especially the snow dumps that last well into summer).

One neat tool that Toronto has used in the past is a snow melting machine. It was used mainly for disposing of snow in tight spots, where you push snow into a hopper with a mini plough and it is melted using diesel heaters and dumped in the storm sewer. Pretty extravagant...

I remember visiting Montreal once in June, and I saw the pitiful remains of a snowbank in the shadow of the Olympic stadium.

akauppi said...

I would say the main problem we have in Helsinki is tight roads that were not built for cars (to be parked). If we can reduce the number of street side parking by half, winter maintenance would be more of a breeze.

On a related note, saw rumour that Bangalore, India might require a car shelter before allowing people to have a car (similar concerns sans the snow).

Dan said...

Dan The Blogger has had to buy a new computer....
Hi guys, just stopping in to say I that I've had a little communication problem lately. I have just started re-installing programs and such... I also have a lot to catching up to do in terms of using a more modern OS! I can't do a thing! Anyway, to QT,.. You are quite right about the torque being extreme in high winds, and I will be working to quantify and address it. Thanks to you all for keeping the thread interesting in my absence! I may be a bit busy for a while, I have an elderly relative going in for surgery in a couple of days, and my old computer ate a lot of my work.