The Privatization of Roads and Highways - Ludwig von Mises Institute

Congestion and Road Pricing 79
There are problems with Thompson’s views, however. For
one thing, they assume far too much. How can we ever know, in
any particular case, of “general agreement” with the proposition
that the price will be so high as to deter all potential motorists
from the C.B.D.? Second, even if there is “general agreement,”
there still may be some consumers with nonaverage tastes who
might willingly patronize the C.B.D. roads, even at what are considered
to be outrageously high prices by most people.
But let us even suppose that at any one time Thompson is
right, and that no one actually would willingly pay the very high
prices needed for access to the city streets. Still, a ban is not a
good approximation of a price system. For someone could change
his mind about the benefits of such travel compared to their costs,
and decide to patronize the road. Under a price system, what
would happen would be akin to any slow-, or non-selling,
highly-priced item suddenly rising in the estimation of the consumers:
more of it can be sold. But under an outright ban, the
whole system will have to be dismantled in order to allow this
change in consumer rankings to be translated into action. It is
only if we assume perfect initial knowledge, and no changes in
consumer preferences thereafter, that the Thompson approximation
makes sense. But these are truly heroic assumptions.
Roth48 has set out four criteria for judging systems which
seek to reduce highway congestion. First, selectivity: a system
should be able to distinguish those road users whose needs for
the service are immediate and pressing from those whose needs
are of a lesser intensity. Second, flexibility: it should discourage
use of crowded roads only, not of empty ones. Third, practicability:
it should be “simple, fair, cheap and enforceable.” Fourth,
remediability: the system should be able to pinpoint the trouble
spots, and act automatically to remove them. And how do automobile
bans, or a system of partial bans, stack up? Says Roth:
48 Roth, Paying for Roads, pp. 70–71.