This response extends my more abstract definition of ST to some fertile
Yes, light rail is not sustainable; only less _unsustainable_ than commuting
by car. Light rail supports far-flung suburbs, while street cars support,
well, street-car suburbs (see "City Life" by Witold Rybczinski, 1995), and
while bus service supports a city form somwhere inbetween. While light-rail
suburbs require one car per driver in the household, bus-transit requires
one car per household, and street-car suburbs require no car.
Likewise, a smaller, more efficient, or alternative-fuel vehicle is also
_unsustainable_ than another private vehicle. It will still take as much
the road and in parking lots, it will still threaten the life and limb of
others, it will
still create noise, and it still will require lots of energy and resources
transport to a dealer, and dispose of when its 'life' ends.
It is an important part of sustainable transport and communities to accept
some principle of organizing communities to respect what I call the scalar
hierarchy, in which the trips taken most frequently are short enough to be
made by walking (even if pulling a small cart), while the next more frequent
trips require a bike or street car, and so on. If one adheres to this
(requiring living in communities organized thusly: medium densities, mixed
_and smaller_ uses), then there are so few trips to be made by car that
owning one is foolish.
Of course, it helps, during a transitional phase of a reture to ST, to have
access to a car everyone once in a while. The is the function of what I
"KyAUTO" (the Kyoto-inspired accessible, utilitarian, transportation
optimizer), or what is provided by cars that are shared: carsharing,
taxis, ridesharing, and simple sharing with family members and neighbours.
"The Only Good Car is a Shared Car"
(Vrtucar's new slogan)