[*BCM*] Observation

[Matthew Arcidy]

On Mon, 7 Mar 2005, Thomas John Vitolo wrote:

> > And if the BPD gets involved, you would have to obey the laws such as
> > traffic lights and
> > stop signs and so on.  
> 
> Doubtful.  In fact, I'd bet what would happen is that the BPD would make it more
> like, ahem, a parade.  They'd likely simply block intersections and give us a
> "free pass" without regard to the light.  It's far easier and safer to keep the
> group together.

If you're going to use Engineering arguments, don't use term's like
"doubtful" and "bet".

>  
> > But I think that if more people did turn out, you could have a road
> > lane full of people,
> > and if they stopped at a light, when that light changed you'd still
> > have a block long of
> > a road lane full of people, and that would be a good thing.
> 
> It doesn't work.  More specifically, it only could work if
>  (a) the distance between lights was nearly identical, and
>  (b) the light cycles were the same period and the same time for that particular
> street, and
>  (c) the cycles timed out to be exactly the pace of the CM.

She's talking about filling up the periodic distance between lights with
people.  Purely a translational thing.  If your argument is true (that
none of these things happen) then perhaps there is an "optimal sized" mass
packet that can travel between blocks that is safe.  You probably know
Stoch, right?  Maybe you could work on this.  Oh, and as most people know
from commuting, the lights are set up to either help the traffic flow or
impede it.  People who actually have their PhD's designed the systems.

> 
> This is derived from queueing theory, of which I'm a graduate student.  Frankly,
> there's no way to keep the mass together if it stops at lights, because even if
> (a), (b), and (c) were met, people on the cross street turning on to the street
> the CM is on would bisect the stream of cycles.  Once you've got a bisected
> stream, that stream could easily get bisected again at the next cycle, etc.  For
> a thought exercise to understand why this is so, imagine a caravan of 10 cars
> driving down Mass ave, all doing exactly the speed limit, and never speeding
> up/slowing down at lights to stay together.  The first car would likely get
> ahead of the last car by over a mile over a 10 mile span.

Also, that's not true.  The probability of hitting a red is the same for
all of them.  The lead vehical could be at a red while the others travel,
depending on the velocity, and such.  I won't bow to this argument until i
see it worked out, and the burden of proof, if you are going to try to be
academic about it, is on you.  So you have a nay-sayer.  Also please
included a distribution of wait times based on the route.  Either way, no
matter how you model the system, your model is imcomplete and only a
model.  Your simple model is rejected soundly based on it's
simplicity, or as professionals like to say, "It's just a theory".


> 
> 
> >  And
> > still, the car traffic
> > could get by, and people could see the beauty of what CM can be.  I
> > think it is just such
> > a shame that it isn't that now, and as CM keeps to the marginal
> > fringes, that margin is
> > going to get narrower andnarrower, which is such a shame.
> 
> Ultimately, since I believe that stopping at lights fractures CM in a way that
> is both far less safe and less effective for CM, I believe that riding in 1 lane
> is also a show-stopper, since it leads to (a) cars trying to make right or left
> turns through the mass, (b) cars speeding to pass the mass (which can be very
> dangerous to the cyclists and any other motorists/peds in the area), and (c)
> added confusion when the CM doesn't stop at a red light, since it's "half" or
> "one third" as wide, and therefore "half" or "one third" as massive from the
> perspective of another set of vehicles preparing to go through the newly green
> light.

Hey, if people followed traffic laws (all people) this wouldn't be an
issue.  you breaking the laws enables them to break them with the same
impungity.

 > 
> 
> In my opinion, CM simply can't function safely or effectively if
> fragmented by traffic lights, or if it allows cars to pass by riding
> in a single lane.  It's best method of keeping cars from growing
> frustrated, if that is important, is to
> not ride along the same road for very long; constant "wiggling" between streets
> and avenues will dramatically reduce the average and worst case waiting times
> for motor vehicles, at the "cost" of distributing the delay amongst many more
> drivers.  Additionally, not riding right at 5:00pm (which the Boston CM doesn't)
> helps tremendously.  The 6:30ish ride is at the back half of rush hour, on the
> day of the week when many more people are likely to leave work early.

You need to rewrite this entire conclusion.  You make wild claims without
substantiation, highly unacademic of you.  Why are you tossing around
terms without defining them?   Cost?  Worst case?  Where's your trendline
young man!

-Matt

ps.  Half of this is tongue and cheek, the other half serious. Just
because you study when to shift bits, doesn't make you an expert on
traffic.  It's a common misconception to beieve that, if we are an expert
in one thing, we must be an expert in other things.

> 
> 
>  - Tommy V
> 
> Thomas John Vitolo
> Ph D Systems Engineering Candidate,
> Boston University
> 
> Support a few technologists in Washington.  Go to:
> http://actblue.com/list/stomv
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