February 25th, 2014

Why do so many propose to ‘increase circulation’ with some transit project without understanding their implicit organic analogue?

Mesentery tissue

Mesentery tissue for example holds your intestines in place and carries all that yummy stuff you just ate from there to the rest of you. Should we wish to increase it’s circulation?

“Circulation” as it’s typically applied to transportation, inevitably by laypeople and politicians1, always seems to base it’s forgone prescription for more on unscientific, ‘holistic’ medicine.

Would anyone care to seriously ask their doctor whether it would be desirable to ‘increase’ or ‘improve’  circulation in some arbitrary body part? To be sure we’re dealing with very different organisms, cities and humans. To start with, I think the most basic distinction we’d need to draw is between evolution by ‘selection’ from among random variation and Lamarkian selection by willed adaptation. Or perhaps between discrete and predictable life cycles and cumulative, adaptive systems.

In any case, what to me is certain is that we need to be explicit about just what type of body we’re operating on before we engage in such reasoning by analogy. Who among the streetcar fanboys has yet done that? And why is the medical community2 so far from such urban discussions with their heavy use of organic metaphor? Is there a doctor in the house?

Show 2 footnotes

  1. I’m not going to provide citations here. Do a search for ‘Cincinnati streetcar circulation’ or something like that and you will find endless examples.
  2. Is this even a community? It’s that far away…

4 responses to ““Circulation””

  1. Danny Howard says:

    In this country, public transit tends to be underutilized with room for added capacity. “Low blood pressure” is the ailment we tend to worry about. Increased circulation might lead to increased service frequency . . .

    The patient is mostly comatose, so getting some blood in the system might help. Outside of New York City and a handful of transit corridors at peak, circulation is definately something in want of an increase.


    • Nate Wessel says:

      Good point! But it’s interesting that I’ve never heard someone argue for shorter headways on the ground that it would ‘increase circulation’. Rather, every time circulation is mentioned it’s in regard to some additional line. If we think of operating funds as blood, an additional line only lowers blood pressure! There may be a valid application of this analogy, and I think you may have just pointed it out, but I haven’t yet seen it in the wild.

      Comas don’t really have anything to do with circulation, at least once they’re established. Hypoxia, such as might result from a cardiac arrest(lack of oxygen to the brain due to stifled circulation) could result in a coma, but if such severely restricted flow continued, the patient would very quickly die. Increasing circulation (whatever that might mean) would not be an appropriate response to a coma, by definition, already in progress and reasonably stable. Where a coma results from severely restricted circulation, it results from the immediate, traumatic impact of acute hypoxia. That effect is lasting even when the flow of blood is restored. That’s what makes it a coma ;-)

      From Wikipedia:

      Coma may result from a variety of conditions, including intoxication (such as drug abuse, overdose or misuse of over the counter medications, prescribed medication, or controlled substances), metabolic abnormalities, central nervous system diseases, acute neurologic injuries such as strokes or herniations, hypoxia, hypothermia, hypoglycemia or traumatic injuries such as head trauma caused by falls or vehicle collisions. It may also be deliberately induced by pharmaceutical agents during major neurosurgery, to preserve higher brain functions following brain trauma, or to save the patient from extreme pain during healing of injuries or diseases.[9]

      Forty percent of comatose states result from drug poisoning.[10] Drugs damage or weaken the synaptic functioning in the ARAS and keep the system from properly functioning to arouse the brain.[5] Secondary effects of drugs, which include abnormal heart rate and blood pressure, as well as abnormal breathing and sweating, may also indirectly harm the functioning of the ARAS and lead to a coma. Seizures and hallucinations have shown to also play a major role in ARAS malfunction. Given that drug poisoning causes a large portion of patients in a coma, hospitals first test all comatose patients by observing pupil size and eye movement, through the vestibular-ocular reflex.[5]

      The second most common cause of coma, which makes up about 25% of comatose patients, occurs from lack of oxygen, generally resulting from cardiac arrest.[10] The Central Nervous System (CNS) requires a great deal of oxygen for its neurons. Oxygen deprivation in the brain, also known as hypoxia, causes neuronal extracellular sodium and calcium to decrease and intracellular calcium to increase, which harms neuron communication.[11] Lack of oxygen in the brain also causes ATP exhaustion and cellular breakdown from cytoskeleton damage and nitric oxide production.

      Twenty percent of comatose states result from the side effects of a stroke.[10] During a stroke, blood flow to part of the brain is restricted or blocked. An ischemic stroke, brain hemorrhage, or tumor may cause such cessation of blood flow. Lack of blood to cells in the brain prevents nutrients and oxygen from getting to the neurons, and consequently causes cells to become disrupted and eventually die. As brain cells die, brain tissue continues to deteriorate, which may affect functioning of the ARAS.

      The remaining 15% of comatose cases result from trauma, excessive blood loss, malnutrition, hypothermia, hyperthermia, abnormal glucose levels, and many other biological disorders.

      So my metaphor-extending question for you is this: What sort of drugs did the US take that got us into this coma? Or what traumatic injury? Treatment options don’t look good, but what might we do to minimize damage to the body while we’re unconscious? What is the social equivalent of aspiration pneumonia, and what exactly causes it? What policies might reestablish consciousness?

  2. James Braye says:

    I imagine “circulation” as a transit concept as the short-distance churning that occurs in communities and that is mostly filled via walking. Helping “circulation” and getting more utilization out of a transit line is (in my experience as a rider) are the same thing and is best accomplished with frequency.

    My favorite example of the above is Columbus Ohio’s COTA #2 line. It has 7 minute weekday frequencies, and runs until 3am on Fridays and Saturdays. I travel to Chicago twice a year. The #2 really does feel like Chicago’s red or blue line in terms of just arriving and waiting for a vehicle without regard to a schedule and without a ridiculous wait. The #2 is an example of a small company running their main line/”circulator” correctly.

    If I was running the show and needed to increase circulation, I would apply the following to a specific line:

    *Stop consolidation, 400m minimum, extending to 800m (preferred).
    *Real time arrival info at all stations.
    *Some level of weather protection at all stations
    *6-8 minute frequencies from 8am-6pm. Surround the 3 hours around that with 15 minute frequencies. 45 minute frequencies for all other hours, 24/7.
    *As much signal prioritization and dedicated roadway as I could get.

    My suggestions are the 43, 17 (with reduced branching), or 78. A “circulation” line without including employment, recreation, and housing is not likely to succeed. Put your resources into making one “rail equivalent” and the people in that thouroughfare will have a reasonable shot at living an extremely car-lite lifestyle (due to the amount of amenities located somewhere on the line and the short waiting times).

    Your point of too much system volume causing the blood pressure to drop is the best analogy I can think of.