Following is a comparison of pollution emitted by various forms of transport.

MODE              HYDRO           CARBON           NITROGEN
                 CARBONS        MONOXIDE           OXIDES

Electric Rail     0.01            0.02               0.47
Motor Bus         0.20            3.05               1.54
Vanpool           0.36            2.42               0.38
Carpool           0.70            5.02               0.69
1 person car      2.09           15.06               2.06

These figures are grams per passenger-mile.  I believe that the Electric Rail
figures do not count emmissions from the power plants making the electricity,
but those plants do have anti-pollution equipment, and electric rail is the
most efficient form of transportation except the bicycle.

23 responses total.

Very interesting figures.  One-person car loses bigtime.

The antipollution equipment on power plants removes primarily particulates
and, in those so equipped (which is not the majority) sulfur oxides. 
In the latter case, some NOX is also removed, but power plants, being
relatively low temperature combustion, are not big generators of NOX.
The equipment doesn't do much to hydrocarbons or carbon monoxide.
The "carpool" category is just 1/3 of the 1 person car. I doubt that
the category "carpool" *average* passengers is 3.00. Well..engineering
approximation. I am not sure what Bill means by "electric rail is the
most efficient form of transportation except the bicycle", as efficiency
and pollution are nto simply related. The  most efficient form would seem
to be either the solar car, or the glider (considering only operating
energy). Zero use of nonrenewable resources.

Not everyone has a cliff to jump off to get to work.

re #2:
As rcurl said, efficiency and pollution are not simply related.  While it is
true that solar cars and bicycles both have equal emmisions, solar cars are 
much bigger and heavier.  The bike is by far the most efficient, in terms of
energy use.  It may be easier to drive a solar car, but that doesn't mean it
uses less energy.

Let's consider the bicycle: its motive power requires fuel, which
requires an enormous infrastructure, a vast chemical industry, a waste
transport and processing facility, a road/path-way network, and of
course it consumes metals, rubber, plastics, etc. Are you sure that
the bicycle is "efficient" and "nonpolluting"?

Let's consider the solar car, also: it too requres a road/path-way network,
which has to be much wider than it has to be for the bicycle, and it, too, 
consumes metals, rubber, plastics, etc.  I assume the part about fuel, the
chemical industry, processing facility... referrs to the rider of the bike.
The driver of a solar car has to eat too (not as much, but the cyclist doesn't
need light).  I never said the bicycle didn't use any energy.  I just said
that it is more efficient than anything else.  Plus, it has all those health
benifits.

Re #5: all of these functions are consequences of living.  The energy
expended is not fossil, so no matter how hard you pedal you don't 
contribute net pollutants in the same way gasoline does.  Re#6: the point
about width is good.  Speed is also a factor.  A six-lane road like
Plymouth road is a barrier to pedestrians even though the nearest traffic
is a quarter mile away (speeding toward you at 50 mph).  The real 
environmental issue about transportation, or at least the most neglected
aspect, is its impact on land use and quality of life, not just air.

How many passengers were on that bus?  The ones around here generally have
between 0 and 6, and emit far more pollution per person than a one-person car.
An electric bus would be a great improvement, but so would a small van.
Ann Arbor used to have a nice electric tram system.  I also prefer biking to
public transportation, but it is too icy Dec-March.  Are there non-skid
(guaranteed) bikes out yet?  And it is a problem getting the helmet on over
two hats, and my hands freeze.   The bicycle uses very renewable energy, and
if people ate more food and exercised more they would have a more nutritious
diet (unless they just ate more junk).  Bikes also outlast any car made - you
just change the brake cables and tires once in a while.  (Except for my
roommate, who manages to break off pedals and handlebars, but only when he
is at least 10 miles from town.)

        There's another very important factor missing, which lead to the demise
of the electric car - although gasoline engines are not very efficient, they
are more efficient than producing electrical power for homes, charging a
hydrogen-cell battery, and storing that energy until it is needed.  It's
significantly more efficient than a centralized power source - such as
nuclear.  It does begin to pay off when you get to local solar-thermal
production.

While you have a point about energy efficiency I think it's very premature
to speak of the "demise" of the electric car.  There are more electric
cars either being produced or coming online now than in any point in
history.

True, however, more due to laws than it being a effective way of doing
business.

        No, the electric car died in the early 1900s.  It's recently been
resurrected due to innovations in technology.  It was, however, a very
popular alternative to steam and gasoline engines - the first Presidential
car was an electric.

        That's what I was referring to.

There were no significant innovations for electric cars since their demise
in the early 1900.  The battery was then, and remains today, the biggest
problem.  The major and minor car Co's are now jumping on the fuel cell
powered car band-wagon.  Recent innovations in fuel cell technology have
turned that concept into a very tempting target and auto Co's are scrambling
to be the first to the bulls-eye.  If this technology pans out, and the
speculation is that it will, it will mark the biggest change to the car
since the model T.  The June 22, 1998 issue of Design News has a good
article on the subject.

It's still touch-and-go (or, is that start-and-stop). The efficient and
economical use of *liquid* fuel cells is what is needed, but no one has
done it. There are a lot of "almost" technologies that would be a great
boon if they could be done - but which have not been done after decades
of trying (e.g., direct oxidation of methane to methanol with high yield).
Not to say they can't be done, but at least a lot of the reasons for the
difficulties are understood (the reaction just won't go that way, is one).

Yes, reformers are used to convert the methanol to hydrogen.  Toyota has
developed a hydrogen absorbing alloy that can hold even more hydrogen in
a given volume than if the hydrogen were in liquid form.  Arthur D. Little
Int'l claims to have developed a reformer that develops hydrogen from 
gasoline.  They claim a 84% conversion efficiency and they say that the
device employs fairly common materials which helps keep the price down.

I'm no chemist by a long shot and I'm sure that there are a lot of got-yas!
but there sure is a lot of research going into this with auto Co. support..

There is lots....all unsuccessful. Gets lots of grants, however, supporting
a lot of breakthrough-wannabees. 

Reforming methane is old hat, though still not economic on a small scale.
Converting methane to hydrogen isn't much use as the step wastes a great
deal of energy. It avoids the problems with using methane directly in
a fuel cell. 

It is not possible to get 84% *energy* conversion efficiency from reforming
gasoline. Taking gasoline as CnHn, from each CnHn you get nCO2 and 0.5nH2.
The heat of combustion (HHV) of CnHn is about 164n kcal/gmole. That of
0.5nH2 is ca. 32n kcal. That's a 20% efficiency. *On top of that* the
*conversion* may only be 84% efficient, giving a net energy efficiency of 16%.
Phooey. 

Bummer.  I hoping that I might witness the demise of the IC engine used in
cars in my lifetime :-(

You may, but I think it will be fuel cells running on liquid hydrocarbons,
when the bugs are worked out. New chemistry and catalysts - and materials
of construction - will have to be discovered./invented I certainly don't
rule this out (nor does thermodynamics). 

I hope the cost of private motor vehicles goes up high enough to restore
public transportation.

Either depletion of petroleum or global warming will make private auto
use exorbitant, probably within 100 years. (Meanwhile, the GOP is
trying to eliminate budget items for alternative fuel and energy conservation
research.)

I hope within less than 100 years, I would like to be able to take electric
trolleys and trains within my lifetime, some day I will be too old to bike.
The technology for both has been around for a very long time.

You can take electric trolleys and trains now - in Pittsburgh and Chicago,
and in any city with subways. Of course, what is needed is the conversion
to mass transit for most suburban and urban travel. 

The problem is that I cannot take the train to reach Pittsburgh, I would have
to take a train to Detroit, a bus to Toledo, wait until 1 a. m. for the train
east (does it go to Pittsburgh?).  A friend wanted to visit by train and could
not find any way to get here in a reasonable amount of time.  The train to
Toledo stopped carrying passengers around 1950.  It would be much faster to
bike than to bus there (four hours total by bus, 60 miles biking, well, maybe
the same amount of time, but much more pleasant and a larger choice of times).

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