3.1 INTRODUCTION
The
discussion of individual locations in the previous chapter placed many
restrictions on the nature of transport costs for the sake of exposing some
fundamental characteristics of location decisions. While we recognized that in
the real world different kinds of inputs and outputs are transferred at
different costs and that weight is often an inappropriate measure of input and
output quantity, we assumed that transfer costs along a route were proportional
to distance. Further, we ignored the fact that transfer generally has to follow
an established route between established terminal service points rather than
going as the crow flies. We also failed to distinguish between money costs,
time costs, and still other kinds of costs entailed in transfer and ignored the
great differences in cost and service capabilities of different techniques or
modes of transfer, as well as the distinction between costs to the transfer
firm or agency and costs to the user of transfer service.
In this
chapter we hasten to remedy these omissions in order to get a more realistic
understanding of how transfer costs affect the location of
activities.
3.2 SOME ECONOMIC CHARACTERISTICS OF TRANSFER
OPERATIONS
It is much
easier to develop an understanding of the complex variations of transfer
services, costs, and rates if we first note some basic economic characteristics
of transfer activities in general.
In transfer
operations (except for a few primitive types) substantial components of the
costs are fixedthat is, they reflect overall and longrun
commitments such as the provision and maintenance of right of way and
terminals. Partly for this reason, transfer operations are characteristically
subject to important economies of scale. Costs per unit of service tend to be
lower (and service more convenient and faster) on routes with larger volumes
of traffic. Likewise, costs are generally lower when larger quantities are
moved in single-movement units (for example, ships, trains, or
aircraft). There are additional savings in transfer cost when the single consignment (that is, what is moved at one time from one specific
location unit to another) is larger. Some of these scale economies apply
principally to costs of actual movement between locations, and others
principally to costs of establishing and operating terminals and such
operations as selling, accounting, and billing.
Because of
these characteristics, firms or public agencies providing transfer services
generally serve many pairs of points and many different classes of customers,
and operate with a substantial element of monopolistic control rather than in
perfect competition. The rates for the various services rendered can be set so
as to recoup disproportionate shares of the transfer operations fixed
costs from rates on those services for which demand is least elasticto
"charge what the traffic will bear."
Finally,
human ingenuity has continually devised new technologies or modes of transfer
to serve various special purposes. Although each new mode may partly supplant
an older one, it is rare for any mode to disappear completely. Somewhere in the
world there is still in use nearly every transfer mode ever devised. Each mode
has special advantages for a certain range of services, and is thus partly
competitive and partly complementary to other modes.
As Table 3-1 shows, transfer operations can be
classified according to means or according to purpose. The purposes of transfer
are to move people, goods, energy, or information from one place to
anotherinformation being broadly defined to include queries, aesthetic
and emotional effects, and in fact all messages via any of the
senses.
The
"hierarchical" ordering in Table 3-1 (as shown by
the fact that the cells below the diagonal are blank) is interesting. It
reflects the fact that the most primitive and versatile means of transfer is
movement of people, which can accomplish any of the four purposes. Specialized
modes of transfer for shipping goods other than on peoples backs can at
the same time serve to transfer energy and information. Still more specialized
means of energy transmission can also transmit information; and finally we have
specialized modes for information transmission (communication) that cannot move
people, goods, or energy.
3.3 CHARACTERISTIC FEATURES OF TRANSFER COSTS AND
RATES
3.3.1 Route Systems and Service Points
Perhaps the
most notable difference between reality and the uniform transfer surface
assumed in the previous chapter is the channelizing of transfer services along
definite routes, which only rarely represent the straight path of shortest
distance between an origin and a destination point.
There are
two distinct reasons for this channelization. One is the economies of traffic
volume already referred to as a nearly universal characteristic of transfer.
Even primitive societies where all transfer is pedestrian generally develop
networks of established trails, which make it easier to move and harder to get
lost. Each mode of transfer has its own set of route-volume economies. If these
economies are substantial up to a large volume, the route network for that mode
will tend to be coarse; if heavier traffic means only small savings, there can
be a finer network of routes providing less circuitous connections between
points.
The second
reason for route channelization is that some areas are naturally harder to
traverse than others. Thus all modes of land transport have reason to favor
level, well-drained land and temperate climate and to avoid unnecessary stream
crossings in laying out routes. All routes crossing major mountain ranges
funnel into a few selected passes or tunnels. Similarly, ocean shipping routes
have to detour around land masses and also have to pay some attention to ocean
currents, winds, shoals, iceberg zones, and of course, the availability of
harbors. As a result, there is a more or less recognized network of regular
"shipping lanes." Even air transport is restricted in choice of routes between
any two terminals by the system of navigational aids and safety
regulations.
Any kind of
communications system requiring either fixed-line facilities (such as cables)
or relay stations is likewise constrained to a limited set of routes. Transfer
is really "as the crow flies" only within the range of direct wave or beam
transmission.
Scale
economies apply not only to route facilities such as trails, track, roads,
pipelines, cable, and navigational aids, but also to "service points" where
transfer by the mode in question can originate and terminate. Thus there are
certain minimum costs of establishing a railroad station or even a siding; the
same applies to piggyback terminals, ports for ships and aircraft, transformer
stations on long-distance electric transmission lines, and telephone exchanges
and switchboards. There is an economic constraint on the spacing of transit
stops along a route, since more stops slow the service. People making shopping
trips generally prefer to do all their errands with a minimum number of
separate stopsexcept for those who view shopping as a
recreation.
Consequently, the pattern of transfer services offered by any
particular mode is always spotty, linking up a limited number of pairs of
points by routes usually longer than the straight-line distance; and a transfer
of a specific shipment, person, or item of information from initial origin to
final destination frequently entails the use of more than one link or
mode.
In addition
to restricting the number of routes and service points, transfer scale
economies in many instances have the effect of making costs and rates lower on
more heavily used routes and to and from larger terminals. This works in
several ways. In some cases, it is primarily a question of direct cost
reduction associated with volume. Thus a larger-diameter pipeline requires less
material and less pumping energy per unit volume carried, and a four-lane
highway can carry more than twice as much traffic as a two-lane highway, with
less than twice as wide a right of way if the median divider is
narrow.
Similarly,
terminals and other transfer service points can often operate more
efficiently if they handle large volumes of traffic. Examples are the huge
specialized facilities for loading and unloading bulk cargoes such as grain,
coal, and ores, and the more specialized equipment found at large
communications terminals.
But apart
from and in addition to such volume-of-traffic savings in cost to the operator of individual transfer services, there are likely to be
important advantages for the users of the services in terms of quality
of service. Your letters will probably be delivered sooner if you put them in a
heavily used mailbox from which collections are made more frequently. If you
are shipping goods to a variety of destinations, it may pay to choose a
location near a large transport terminal, not only because the departures are
more frequent but also because there are direct connections to more points and
a variety of special types of service.
3.3.2 Long-Haul Economies
Virtually
every kind of transfer entails some operation at the point of origin prior to
actual movement, and also some further operation at the destination point. The
cost of these "terminal" processes ordinarily does not depend on the distance
to be traveled, whereas the costs of actual movement ordinarily do.
Because of
these terminal costs, the relationship between route distance and the
total costs of a shipment will generally behave as shown in Figure 3-1. Transfer costs are characteristically less
than proportional to distance, and the average transfer cost per mile decreases
as the length of haul increases. This principle is a fundamental one and
appears in every kind of transfer mode, even the simplest. When we leave our
homes or work places on various missions, there is almost always some act of
preparation that imposes a terminal cost in terms of time. Even if we go on
foot, we may first have to make sure that we are acceptably clad against the
strictures of convention or weather, turn off the television, put the dog out,
and lock the door. If we drive, the car has to be activated. If we use public
transit, we have to wait for it to appear.
In Figure 3-1 the costs of movement per se (called the line-haul costs) appear to be nearly proportional to distance. That is,
the slanting lines in the figure are not very curved for hauls of more than a
hundred miles or so. This implies that the marginal cost of transfer (the cost
for each added unit of distance) is constant. We can think of a few
circumstances in which movement costs per se might rise faster than in direct
proportion to distance, such as the case of a perishable commodity where it
becomes increasingly difficult and expensive to prevent deterioration as time
passes, or the case of journeys where after a certain point further travel
becomes disproportionately more irksome. But these are rare exceptions. In
general, we can expect movement costs to be either less than proportional or
roughly proportional to distance.
When might
they rise at a slower than linear rate? This can be expected in the case of
transport of goods or people, since it takes some time to accelerate to
cruising speed and to decelerate to a stop. An example is the case of transit
vehicles with their frequent stops. A one-mile journey between subway stations
takes considerably less time and energy than two half-mile journeys. Somewhat
more complicated instances are those of intercity trucks, buses, or ships,
which have to thread their way slowly through congested areas in the first and
last parts of their journeys, and that of the airplane, which has to climb to
cruising altitude and down again as well as to follow the prescribed takeoff
and landing patterns. In all these cases, the overall speed of a trip increases
with distance even if cruising speed is constant. Speed is not merely an aspect
of quality of service but an important determinant of the costs of rendering
the service, since such items as the wages of vehicle operators, interest on
the capital invested in vehicles, insurance, and part of the vehicle
depreciation are proportionate to time rather than distance.
For long
hauls, such line-haul economies are of course relatively less significant. The
difference in overall speed between an 800-mile and a 900-mile rail or truck
haul is probably not great.1 And in the case of
telecommunication or electric power transmission, which do not entail moving
any tangible objects over the route and in which transfer time is negligible,
it is not obvious that average line costs per mile should systematically fall
with greater distances. Line losses on transmission lines are proportional to
distance, and booster or relay stations on cable or microwave communication
routes are needed at more or less uniform distance intervals. For radio wave
communication, however, the required transmitter power rises as the square of
the range.
3.3.3 Transfer Costs and Rates
As was
noted earlier, many kinds of transfer service are performed by parties other
than the user, and the usual presence of substantial fixed costs and limited
competition gives a transfer agency a good deal of leeway in shaping
tariffs so as to increase profits. Some classes of traffic may accordingly be
charged barely enough to cover the out-of-pocket costs they occasion, while
others will be charged far more than their pro rata share of the transfer
agencys fixed costs. The general principle governing profit-maximizing
price discrimination is to discriminate in favor of customers with more elastic
demands and against those with less elastic demands.
Moreover,
the rates charged by transfer agencies are themselves only part of the total
time and money costs entailed in bridging distance. At longer distances, sales
promotion and customer servicing are more costly or less effective, and larger
inventories need to be held against fluctuations in demand or
supply.
Traffic Volume. Taking these considerations into
account, we can see that the advantages of location at or near larger transfer
terminals can be even greater than was suggested earlier. At such
concentrations of terminal activity, there is more likelihood of sharp
competition among rival transfer agencies of the same or different modes. The
bargaining power of transfer users is greater and their demand for the services
of any one particular transfer agency is more elasticconsequently, they
may get particularly favorable treatment in the establishment of rates or
especially good service, over and above the cost and service advantages
inherent in the scale economies of the terminal operations
themselves.
Relation of Rates to Length of Haul. In the
relation between short-haul and long-haul rates, matters cannot be quite so
simply stated. First, a transfer agency with a monopoly would generally be
impelled to set rates discriminating against short-haul traffic. With reference
to Figure 3-1, the line showing rates in
relation to distance would then have a flatter slope than the line showing the
relation of costs to distance.
The
rationale for such discrimination is that for longer hauls the transfer charge
is a larger part of the total price of the goods at their destination than it
is for a shorter haul of the same goods. Consequently, the elasticity of demand
for transfer service is likely to be greater for longer hauls, and the rational
monopolist will discriminate in favor of such hauls. (See Appendix 3-1 for a simple mathematical statement of
this point).
In
practice, however, a single transfer agency is unlikely to hold a monopoly over
a very wide range of lengths of haul. The greater the distance, the more likely
it is that there will be alternative providers of the same mode of service.
Even more to the point is the probability of effective intermodal competition.
Each
technique or mode of transfer has its own cost and service characteristics and
is more efficient than other modes for some classes of service and less
efficient for other classes (were this not so, we would not have the variety of
modes that exists). Thus jet aircraft excel in providing fast long-distance
transport; waterways and pipelines are generally the cheapest ways of moving
bulk materials in large quantities; the motor vehicle has special advantages of
flexibility and convenience in local and short-distance movement; and so on.
Clearly, if we are considering a wide range of lengths of haul for some
commodity, the lowest-cost mode for short hauls need not be the same as the
lowest-cost mode for long hauls. The cost gradients might be expected to
intersect as in Figure 3-2, which has often been used
to represent truck, rail, and water transport costs but would also be
applicable to a variety of other intermodal comparisons.
In a
situation similar to that in Figure 3-2, the operators
of each mode will find that the demand for their service is particularly
elastic in those distance ranges where some alternative mode can effectively
compete for the traffic; consequently, there is likely to be competitive rate
cutting on those classes of traffic. The final rate pattern might look
something like the black line in Figure 3-2. For each
distance range, the lowest-cost mode determines the general level of rates, and
the progression of rates is rounded off in the most competitive distance ranges
where two or more different modes share the traffic.
We would
expect this outcome regardless of whether the rates in question are for the
transport of goods, energy, or people or for communication, since the essence
of the situation is that different modes have comparative advantages for
different distances. The effect, as graphically shown in Figure 3-2, is to make the gradient of transfer rates
with respect to distance much more curved than the single-mode transfer cost
gradients shown earlier in Figure 3-1. In other words,
the tendency to a falling marginal cost of transfer (to the user) with
increased distance is accentuated. We shall see later the locational
implications of this and the other characteristics of transfer cost and rate
gradients being noted here.
Competitive and Noncompetitive Routes. Still
another way in which comparative rates differ from comparative transfer costs
is with respect to different routes. Between some pairs of points there is
effective competition among two or more alternative transfer agencies or modes,
while between other pairs of points one agency or mode has such a cost
advantage as to constitute, for practical purposes, a monopoly. The margin
between rates and out-of-pocket costs will be small where there is effective
competition and large where there is more monopoly power.
The effects
of this kind of discrimination on transfer rate structures are discussed in
considerable detail in every textbook on the economics of transportation,
usually in reference to the structure of railroad and truck freight rates as
affected by competition among the rail, highway, and waterway modes and among
alternative railroad routes. Recent efforts toward regulatory reform have
substantially lessened restrictions on rate-setting practices. Previously,
complex pricing rules were often established in the interest of some rather
elusive objectives of maintaining competition and preserving equities of
particular areas and transport agencies, which placed limits on rate-setting
behavior of the sort just described. While the legacy of these regulations is
still in evidence, much more flexibility in rate setting is now
permitted.
Discrimination Among Services and Commodities. The locational significance of transfer rate differentials among
different goods or services was taken into account in our discussion of ideal
weights in Chapter 2. Let us now see how such
differentials arise.
Some
transfer services are by their nature costlier to provide than others, and we
should expect to see such differences reflected in rates. A ton of pingpong
balls or automobile bodies is much bulkier than a ton of steel plates. Since
extra bulk adds to transport cost in every mode of transport except possibly
the use of pack animals or human carriers, we are not surprised to see
systematically higher freight rates per ton on bulky goods. This is one basis
for the official commodity classifications governing regulated tariffs.
Similarly, we should expect to pay more for shipping a perishable, fragile, or
dangerous commodity (such as meat, glassware, or sulfuric acid). Extra-fast
service and the carrying of small shipments are more expensive. In passenger
transport it costs more to provide extra space and comfort. In addition, the
marginal costs of added service at slack times are far less than at times of
peak capacity use of the facilities, so that we are not surprised to be charged
more for a long-distance phone call during business hours, for using a parking
lot on the afternoon of a football game, or for crossing the Atlantic in
summer.
None of the
foregoing differentials in rates necessarily involves any discrimination on the
part of the transfer agency, since in every case there is an underlying
difference in costs that is passed on to the user.
But there
are still further systematic transfer rate differentials that reflect
discriminatory rate-making policy rather than costs. In particular, we find
that rates are high relative to costs for the transfer of things of high value,
and low relative to costs for things of low value.
The
rationale is essentially the same as that already adduced in the case of long
versus short hauls; namely, that a sellers profits are enhanced by
discriminating against buyers with relatively inelastic demands and in favor of
buyers with relatively elastic demands.
When a
commodity such as cigarettes or scientific instruments, with a high value per
pound, is shipped any given distance, transport costs will be a smaller part of
the delivered price than will be the case when a low-value commodity such as
coal or gravel is shipped the same distance. Consequently, the demand for
transport of cigarettes will be much less sensitive to the freight rate than
will the demand for transport of coal, and any rational profit-seeking
transport agency will charge a higher margin over out-of-pocket costs on
cigarettes than on coal. Such discrimination, by the way, is not merely in the
interest of the carrier but under some conditions may serve the public interest
as well, through promoting a more efficient allocation and use of resources. It
may enable a greater amount of transfer service to be provided with any given
amount of investment in transfer facilities.
Consequently, we find that freight tariff classifications and special
commodity rates rather systematically reflect the relative prices per ton of
the various commodities, in addition to such other factors as have already been
mentioned. This means that finished goods as a rule pay much higher freight
rates than do their component intermediate goods or raw materials, since
production processes normally involve getting rid of waste components and
adding value.
For the
transfer of people and for communication, the measure of unit value
corresponding to the price per pound of a transported commodity is not so easy
to assign or visualize. The basic rule of transfer rate discrimination
according to value still applies; but it is generally obscured by the fact that
in the transport of people and information, a "higher-value" consignment is
given a qualitatively different transfer service.
When it is
a question of passenger travel, people will set their own valuations simply in
terms of how much they are willing to pay for a trip rather than forgo it.
Transfer agencies do not attempt to charge what the traffic will bear on a
person-by-person and trip-by-trip basis but often provide special services
(higher speed, greater comfort, and the like) to those willing to pay more.
Similarly in the case of communications, it is generally impossible for the
seller of the service to judge how valuable a particular transmission is to the
communicator and charge accordingly; but a choice of different speeds or other
qualities of service can be set up, and the rates for these can be adjusted in
such a way as to reflect the estimated relative elasticities of demand as well
as the relative costs. Lower long-distance telephone rates on nights and
weekends are an example.
Differentiation of Rates According to Direction. Most modes of transportation use vehicles that must be returned to the
point of origin if the trip is to be repeated. Only by coincidence will the
demand for transport in both directions balance. Ordinarily one direction or
the other will have excess vehicle capacity that could accommodate more goods
or people at an extremely low out-of-pocket cost. A rational rate-making policy
will then quote lower back-haul rates in the underutilized
direction.
That
direction can sometimes change rather oftenfor example, in intraurban
travel there is a morning inbound and an afternoon outbound rush hour, and in
some instances lesser reversals around the noon hour and in the evening. On
weekends there is a reverse pattern of recreational travel from and to the main
urban area. In this particular case, highway and bridge tolls and transit fares
do not embrace the back-haul pricing principle, but they easily could, and it
might be persuasively argued that they should.
Differentiation of charges on passenger travel according to direction
is likewise not applied to intercity or other interregional travel within a
country. We might wonder why not, in view of the frequency of the practice in
commodity transport. The essential difference between people and goods in this
context is that people want to return home eventually and goods do not.
Accordingly, "people flows" have a natural tendency to balance out over any
substantial time interval. On certain international travel routes, however, the
seasonal imbalance of travel demand is enough to induce airlines and shipping
firms to vary their rates seasonally according to direction, and there have
been at times special one-way bargain rates to entice permanent migrants to
areas considered underpopulated.
Interestingly enough, there are a few kinds of goods transport that
use no durable vehicles and for which there is consequently no question of
back-haul rates. Some rivers are one-way routes for the transport of logs or
for primitive goods-carrying rafts that are broken up at the down-stream end,
and pipelines normally operate in similar one-way fashion. Telecommunications
media and power transmission lines likewise have no back-haul problem. Nothing
is moved, so nothing needs to be brought back.
Simplification of Rate Structures. The foregoing
discussion gives some idea of the many "dimensions" in which transfer rates can
logically be differentiated: according to mode, direction, specific origin and
destination, quality of service, size of consignment, and nature of the
commodity or service transferred. Clearly, there is some point at which
detailed proliferation of individual rates produces a tariff schedule of
impractical complexity, and various simplifications and groupings commend
themselves.
The variety
of rates charged for transport of different commodities, for example, is held
within bounds by assigning most commodities to one of a limited number of
classes and letting a single schedule of rates apply to that class as a whole.
The determination of individual rates for each and every pair of points served
by a transfer system is analogously simplified by grouping some of these points
into zones or rate blocks. For example, rail freight rates for some
commodities between Pittsburgh and other parts of the country are applied not
just to Pittsburgh proper but to a much larger area embracing the major part of
six contiguous counties. Rate setting behavior of this type is particularly
prevalent when competitive pressures do not force a close correspondence
between the transfer agencys actual costs and the prices that are
charged. An illustration of the application of the rate block principle to
rates graded by route distance is shown in Figure 3-3, which gives us a still more realistic picture of rate patterns than we had in
Figures 3-1 and 3-2.
3.3.4 Time Costs in Transfer
We have
already indicated one way in which the time consumed in transfer is felt in
costs: Both the labor and the capital used in the transfer operation are hired
on a time basis, so the labor cost and the capital cost of a trip will be less
if the trip is faster. It is the high speed of aircraft, particularly jets,
that enables them to transport passengers and certain kinds of freight at costs
per mile comparable to those of ground transport. The capital and labor costs
per hour are spread over at least ten times as many miles.
Quite apart
from this, speed means cheaper transfer for users because they bear "inventory
costs" associated with the length of time that the trip takes.2 In goods shipments, there is the cost of interest on the
capital tied up in shipments in transit, insurance premiums, and the risks of
delayconsiderations obviously more weighty when interest rates are high.
Moreover, many kinds of goods deteriorate so rapidly with the passage of time
that it is well worth paying more for their fast delivery. There are the
obvious physical perishables such as fresh meat, fish, fruit, or vegetables,
and also a further class of perishables such as fashion clothing, magazines,
and newspapers, which lose value as they become out of date. In the
transmission of information, the very word "news" suggests quick perishability,
and the more quickly perishable forms of information provide a rapidly rising
demand for a variety of telecommunication services.
Finally, in
the transfer of human beings, the time of the user of the service is even more
highly valued than are the rather high costs of transporting this delicate type
of freight. The basis for the high valuation placed on travel time is primarily
that of opportunity cost. People begrudge the time spent in traveling because
they could be using that time pleasantly or profitably in some other
way.
The value
each of us imputes to the time spent on travel can vary greatly according to
circumstances, length and purpose of the trip, and the characteristics of the
person. Recreational travel is supposed to be a pleasure in itself. For such
obligatory journeys as commuting to work, it is sometimes suggested that the
commuters hourly earnings rate while working should be applied to the
travel time also. However, such a basis may well be too high.3 In order to suggest the magnitude of time costs of human
travel, let us consider the case of an individual who values his travel time at
$7.50 an hour. If he travels, say, at 30 miles an hour, his time costs are 25
cents a mile, comparable to the money costs of driving a standard car.
Decisions by commuters concerning the use of alternative transfer modes can
easily be influenced by costs of this size.
3.4 LOCATIONAL SIGNIFICANCE OF CHARACTERISTICS OF TRANSFER
RATES
We have
seen that the structure of transfer rates departs markedly in a number of ways
from the straightforward proportionality to distance that was assumed in our
simplified discussion of individual locations in Chapter 2. What does this mean in terms of modified conclusions or new
insights?
3.4.1 Effects of Limited Route Systems and Service
Points
In our
initial discussion of transfer orientation, the economic advantages of
proximity to markets and input sources were envisaged as conflicting forces,
and the most profitable location appeared as the point on a two-dimensional
surface where these forces just balanced.
Some route
networks are so dense that transfer can be effected in an almost straight path
between any two points. A relatively close approximation to a uniform transfer
surface is a city street system; though even here the shortest possible route
and the fastest possible route may both be substantially longer than
crow-flight distance. But on a coarse route network, the locational pulls
toward input sources and markets are exerted in a one-dimensional way, along
the routes. Does this significantly affect orientations of specific units of
activity?
The best
way to visualize the effect is to consider a route system connecting three
points, A, B, and C, which we might identify as the market
and the sources for two transferable inputs for a unit of some type of economic
activity. Figure 3-4 shows four different
configurations that this route system might take.4
Let us now
assign ideal weights to A, B, and C. It is easy to see
that if any of these ideal weights is predominant (exceeds the sum of
the other two), there is no contest: That point is the optimum location so far
as transfer costs are concerned, regardless of route layout. But what if the
ideal weights are more evenly balanced, with none predominant-say, 2, 3, and 4
for A, B, and C respectively? These are the weights shown in
parentheses at the A, B, and C points on System 1 on the
left side of Figure 3-4.
In System
1, we see that the optimum location now turns out to be B. For
all possible locations between A and B, there would be a
net gain in moving toward B, since in that direction we have a pull
corresponding to the combined ideal weights of B and C, or
3 + 4 =7, whereas there is a counterpull toward A of only 2. The
strengths and directions of these pulls are shown by the small circled numerals
with arrows attached. If the ideal weights represent, say, cents per mile per
unit of output, then there will be a net transfer cost saving of 5 cents per
unit of output in moving 1 mile closer to B from any alternative
location to the left of B. Similarly, we find that for any
location between B and C, there is a net gain of 1 cent
per unit of output (3 + 2 4) from shifting the location 1 mile nearer B. Once we are at B, there is no incentive to shift
farther; the optimum location has been found.
This device
of totaling the forces in each direction and thus finding the favorable
direction of location shift along each route segment is a handy technique for
analyzing network location in simple cases and is the conceptual basis of the
linear programming approach for determining the optimum point.5
Let us now
apply this procedure again to System 1 of Figure 3-4,
changing the ideal weights from 2, 3, and 4 to 4, 2, and 3, as shown in the map
at top right in the figure. Again we come out with the intermediate point B as the optimum location, despite the fact that it has the
smallest ideal weight of the three! We begin to suspect that there is some
special advantage in being in the middle; and this is, in fact, the "principle
of median location," mentioned in Chapter 2. If we have three points arranged
along a route as shown, and if none of their ideal weights is predominant, then
the transfer orientation is always to the middle point.6
Applying
the same procedure to System 2 of Figure 3-4 (and
still assuming that none of the ideal weights is predominant), we find that the
optimum point is the junction J. In System 3 it is A, J, or B, depending on the relative lengths of the route segments AB,
BJ, and AJ and the ideal weights of A, B, and C. And in System 4 it could be A, B, or C. We note,
then, that in every one of the four systems the optimum location is always at
an intermediate point (one from which routes lead in at least two directions)
and never at an end point.
This holds
true regardless of the ideal weights so long as none is predominant, and
regardless of the length of the dead-end route segments (AB and BC in System 1; AJ, BJ, and CJ in System 2; CJ in
System 3). Finally, it is quite immaterial which of the points are markets and
which are input sources. In these illustrations, such identification was
deliberately avoided.
It is clear
that when none of the ideal weights predominates, we cannot predict the
orientation of a locational unit simply on the basis of its inputs and outputs;
we can say, however, that it will locate not at dead ends but at points
reachable from at least two directionswhether these be input sources,
markets, or junctions.
3.4.2 General Locational Effect of Transfer Rates Rising Less than
Proportionally with Distance
Ideal
weight expresses extra cost imposed per unit of added distance in other
words, the marginal cost of transfer with respect to distance. Our initial
image of the relation of transfer cost to distance (Figure 3-1) showed this
marginal cost as almost uniform, corresponding to a constant ideal weight
regardless of distance.
The more
realistic transfer rate gradient in Figure 3-3,
flattening off at longer distances, implies that ideal weights and the
locational pulls of transfer cost factors are not constant but systematically
weaker at long range and stronger at short range. If we seek a physical
analogy, then, it should not be that of a weight on a string as in the Varignon
Frame, nor that of a stretched spring, but that of a force more like
gravitation or magnetism.
This
feature of transfer rates tends to enhance the advantages of location at input
sources and markets and to reduce the likelihood of location at intermediate
points. Each input source and market point, in fact, becomes a local optimum
location, in the sense that it is better than any location in the
immediately adjacent area. The search for the most profitable location for a
unit, then, is a little like the search for the highest altitude in a landscape
studded with hillocks and minor and major peaks. In such a landscape, we could
not rely on getting to the highest point by simply continuing to walk uphill
but would have to make some direct comparisons of the heights of various peaks.
Analogously, a program for determining the ideal location of a
transfer-oriented activity unit generally cannot rely entirely on gradients of
transfer cost or measurements of ideal weights but at some stage must
incorporate direct comparison of specific source and market
locations.
This
principle is illustrated graphically in Figures 3-5 and 3-6. In Figure 3-5, we have the transfer
charges per unit of output as they would be at various points along a route
running through the input source and the market point. The two black lines show
how the input transfer and output transfer charges per unit of output vary with
location of the facility. The white line at the top of the figure shows total
transfer charges on a unit of output plus the amount of input required to
produce it.
It will be
observed that there are local minima of total transfer charges at the input
source and at the market. In this case, the total costs for a location at the
market would be slightly lower than for a location at the source, but both are
much lower than those at surrounding locations.
Figure 3-6 shows a two-dimensional pattern of profits
with three transfer points involved: They could be, say, two input sources and
a market. Here the profits per unit of output7 are
shown by contour (iso-profit) lines connecting points of equal
advantage. A local peak appears at each of the three points, with that at
S2 the highest.
3.4.3 Modal Interchange Locations
It has been
suggested above that the long-haul discount characteristic of transfer costs
and rates lessens the transfer advantages of locations that are neither sources
nor markets for transferable inputs and outputs. Some kinds of intermediate
points, however, are relatively attractive in terms of transfer
costs.
Most
transfers involve one or more changes of mode or other terminal type of
operation en route rather than proceeding right through from initial origin to
final destination. This situation becomes more frequent as the variety of
available transport modes increases, each with its special advantages for
longer or shorter hauls, larger or smaller shipments, high speed, low money
cost, and so on.
Textbooks
often tell us that points of transshipment or modal interchange,
such as ports, are particularly strategic locations because location of a
processing facility at such a point "eliminates transshipment
costs."
Such a
statement may be misleading. Let us take a simple hypothetical case involving a
flour mill. Grain is collected at an inland point connected by rail to a port
(transshipment point), from which ships go to a market for flour. We want to
choose among three possible locations for the mill: (1) at the grain-collection
point, (2) at the port, or (3) at the market. To focus directly on the question
of the transshipment points possible advantage, we assume that the
handling and transfer costs (per barrel of flour) are the same for flour as for
grain, which makes the grain-collection point and the flour market equal in
locational advantage. The question, then, is whether location at the
transshipment point (port) is superior or inferior to the grain-source and
flour-market locations for the mill.
Let us
denote the elements of cost as follows, per barrel of flour:
M |
Milling cost |
L |
Cost
of each loading of grain or flour |
U |
Cost
of each unloading of grain or flour |
R |
Cost
of shipping grain or flour from the collection point to the port |
W |
Cost
of shipping grain or flour from the port to the market |
The costs
involved for each of the three mill locations are as itemized in Table 3-2.
We notice
that for each of the three possible mill locations, the total cost is the same: M + B + W + 2(L + U). Although the
transshipment point location is apparently just as good as either of the
others, it does not show any special advantage. Indeed, we might surmise that
more realistically it would be under some handicap. With either of the other
two mill locations, it might be possible to achieve some savings by direct
transference of the grain or flour from rail to ship (the U and L operations at the port) at less cost than is involved in the two separate
port transfers (grain from rail to mill, and flour from mill to ship) that are
involved if the mill is located at the port. This possible saving is suggested
by the square brackets in Table 3-2.
If we
modify the preceding case by assuming that flour is more costly to ship,
unload, or load than is grain, then the most economical location is at the
market; location at the grain-collection point would be less advantageous, and
location at the port would be intermediate in terms of cost.
Clearly,
then, we must explain the observed concentrations of activity at ports and
other modal interchange locations on the basis of other factors. Some (the
transport advantages of junction points with converging or diverging routes)
have already been mentioned. A modal interchange point is likely to have such
nodal characteristics, if only because different transfer modes have route
networks of different degrees of fineness, so that where they come in contact,
there is likely to be more than one route of the mode with the finer
network.
The
focusing of transfer routes upon points of modal interchange reflects scale
economies in transfer and terminal operations, and sometimes also the lie of
the land. Thus along a coastline, suitable natural harbors are limited in any
event, and scale economies tend to restrict the development of major ports to
an even smaller selection of points. The same applies to crossings of a
mountain range or a large river.
A further
characteristic advantage of modal interchange points is that they are likely to
be better provided with specialized facilities for goods handling and storage
than are most other points.
3.5 SOME RECENT DEVELOPMENTS CONCERNING THE STRUCTURE OF TRANSFER
COSTS
3.5.1 Introduction
The
preceding sections have focused on some important aspects of the structure of
transport rates and characteristics of route systems. As has been demonstrated,
they provide information that can be used in conjunction with the theoretical
insights gained from Chapter 2 in order to appreciate more fully the role that
transfer factors may play in location decisions. In some instances, changes
that take place in the markets of important commodities in a national or
international context or changes in basic technological relations can have
direct effects on the spatial distribution of economic activity. These effects
often, but certainly not always, manifest themselves as a result of changes in
transfer costs.
In this
section, attention is directed to two such changes, both much in evidence at
this time. We attempt to use the location principles that have been developed
in order to understand some of the spatial consequences of higher energy prices
and technological changes concerning the processing and transmission of
information. It should be emphasized that our treatment of issues related to
these phenomena is speculative and illustrative. There is a very slim factual
basis on which to gauge any of the effects that will be mentioned. However, it
is hoped that this analysis will demonstrate how even elementary location
theory can help us to speculate constructively.
3.5.2 Higher Energy Prices and the Pattern of Industrial
Location
The rapid
increase in energy prices during the decade of the seventies affected our
economy in many ways. We are acutely aware of the impact of this phenomenon on
the rate of economic growth as well as on the distribution of income. However,
little attention has been paid to the effect of higher energy prices on the
spatial distribution of economic activity. It is important to recognize these
spatial effects as well as the mechanics by which they are
transmitted.
The effect
of higher energy prices since the 1970s on locational choice might be
considered from several perspectives. It would be possible, for example, to
examine the nature of commuting or shopping behavior when people are confronted
with higher motor fuel prices. Alternatively, we might recognize that higher
energy pries have affected production decisions as well as the transport costs
on material and finished products. This being so, our previous analysis of
transfer-oriented industries would imply that, for at least some locational
units, the spatial consequences of higher energy prices will depend on the
nature of responses in production and the kind of changes in the structure of
transport costs that take place. Much of the preceding discussion in this text
has pointed to the result that the orientation of industry toward particular
inputs or toward the market can be influenced by these locational determinants.
We are well equipped to understand many issues related to the effects of higher
energy prices if we examine the systematically in this context.
It has been
pointed out (see Figure 3-2) that intermodal
competition among transfer agencies leads to a gradient of transfer rates with
respect to distance that is much more curved than that of any single-mode cost
gradient. For long hauls, customers will find that the decrease in transfer
rates with increased distance is accentuated by competition of this sort. The
locational significance of this characteristic of transfer rates is that it
puts intermediate locations (places that are not markets or sources of
transferable inputs) at some disadvantage.
One channel
by which higher energy prices might affect location decisions is through their
effect on the structure of intermodal transfer costs.8 As shown in Table 3-3, transfer modes differ in their
intensity of energy use. Specifically, shorter-haul transport by motor carriers
(trucks) is most energy intensive, whereas rail and barge transport, which
generally involve longer distances, are much more energy efficient. The most
direct consequence of this is that we might expect the tapering off of
transport rates with distance to become yet more accentuated as a result of
higher energy prices; short-haul (truck) rates will increase relative to
long-haul (rail and barge) rates. By our earlier arguments, the attractiveness
of end-point locations is enhanced as a result of this effect.
TABLE 3.3: Domestic Intercity Freight Movement: Energy Intensity and Average
Length Haul by Major Transport Modes, 1979* |
|
Energy Intensity
/ (Btu /
ton-mile)
|
Average Length of Haul (miles)
|
Truck |
2380 |
270 |
Rail |
625 |
595 |
Waterborne
commerce |
440 |
770 |
*Data on certified
route air carriers are also presented in this source. They indicate that while
air transport is very energy intensive (7780 Btu / ton-mile), relatively little
tonnage is involved. Air carriers accounted for only 1/10 of 1% of total
tonnage shipped in 1979.
Source: G.
Kulp, D. B. Shonka, M. C. Holcomb, Transportation Energy Conservation Data
Book: Edition 5 (Oak Ridge, Tenn.: Oak Ridge National Laboratory, 1981),
Table 1.13, p. 1-26. |
The
differential impact of higher energy prices on alternative modes of transport
can be expected to have more subtle effects, however. Modes differ not only in
their competitiveness by length of haul, but also in the kinds of commodities
that they can most effectively transport. For example, not only is trucking
particularly suited for the transfer of commodities over short distances, but
it is also best suited to commodities that have a high ratio of value to weight
and to commodities that must be shipped in small lots.9 Both of these characteristics encourage the use of trucks
to deliver finished and other highly processed goods to market. Conversely,
because of the high fixed costs and relatively low line-haul costs associated
with rail and barge modes, they not only have an advantage on longer hauls but
also are particularly suited to the transfer of bulk commodities with low value-to-weight ratios, a category that often includes raw
materials.
These
considerations imply that the changes in relative freight rates (truck versus
rail or barge) that are the result of higher energy prices may have some
significant effect on material versus market orientation. The energy intensity
of truck transport will be reflected in higher line-haul rates for this mode as
compared to other modes. Additionally, because of the relatively inelastic
demand for transport services associated with high value-to-weight commodities,
more for the energy price increases can be expected to be passed on by agencies
serving this class of goods. Smaller portions of energy price increases will be
passed along by those modes that service low value-to-weight commodities
because of the sensitivity of their demand to price increases. Therefore, in
the tug-of-war governing location decisions for industries that are sensitive
to transport costs, we should expect that the pull of the market will be
enhanced relative to that of transferable inputs as transport rates on finished
goods increase relative to those associated with materials.
We should
recognize that this analysis concentrates on only one component of the "ideal
weight" measures defining locational pulls. It has been argued that energy
price increases will be reflected in transport rates. The other component of
ideal weight is, of course, the physical weight of the transferable input or
output. There are some evidence that the materials and energy are substitute
inputs in the production process associated with U.S. manufacturing as a
whole.10 This would imply that an increase in
energy prices may increase the weight of materials transferred for output of a
given weight. Such a change would tend to increase the ideal weight of
materials and may serve to counteract any tendency toward market orientation
due to changes in relative transport rates. The highly aggregative nature of
empirical evidence concerning this matter precludes any definitive judgment,
however.
Higher
domestic energy prices not only affect transport and production costs, they
also imply substantial shifts in the spatial distribution of income.
Energy-producing regions have gained for at least two reasons. Greater local
production at higher prices obviously has meant greater income to workers as
well as to the owners of capital in these regions.11 Further, while price controls on domestic petroleum and
natural gas production are being phased out, the presence of these restrictions
has meant at least a short-run advantage to energy consumers in
energy-producing regions. They have faced relatively lower energy prices than
they would in regions that must rely exclusively on higher-priced, imported
energy. Therefore, recognition of the concept of "market access potential"
developed in Chapter 2 would indicate that for
some locational units higher energy prices mean that the median location of the
market will shift in the direction of those regions with substantial existing
or developing capacity in energy production.12
While we
have been able to identify certain gross tendencies that may be manifest as a
result of higher energy prices, this analysis is only suggestive of the kind of
forces at work. Individuals who are concerned with the behavior of specific
industries could obtain more detailed information on transport modes and on the
character of production and markets that are relevant to their interests. They
might then be in a position to know whether transport rate, production, or
market considerations will be most influential.
3.5.3 Technological Change in Data Processing and
Transmission
In contrast
to the behavior of energy prices, the cost of moving and processing information
has fallen dramatically in recent years, and the end is not in sight. Advances
in electronics technology have abruptly enhanced the efficiency of computers
and our ability to interact with them. At the same time, developments in
communications technology have weakened the constraints of distance on some
types of location decisions. Significant locational effects are emerging on
both the microspatial and the macrospatial levels, foreshadowing still further
shifts.
As we shall
see in Chapter 7, the internal spatial
arrangements of urban areas are shaped largely by considerations of
accessit might even be said that access is what cities are all about. At
this microspatial level, the journey to work and ones ability to maintain
close, flexible contact with customers, suppliers, co-workers, and friends are
major determinants of both business and residence location. So if people or
firms find that their work and other activities no longer demand close physical
contact, locational incentives will change. For example, it is now becoming
increasingly practicable to use computer hookups to communicate with other
workers or with central data banks. As a result, the valuation of locations
with respect to their nearness to long-established foci of urban economic
activity is changing considerably. This "communications revolution" has
potentially wide implications. Some people have speculated that the "cottage
industry" of the near future will comprise people who work at home and maintain
business contacts via integrated computation and communications systems. Early
evidence of such a trend is already appearing.
For some
activities, the very nature of outputs or inputs, or both, may change as a
result of advances of the sort just mentioned. Banking is an obvious case in
point. From one perspective, deposits received by a bank may be regarded as
inputs; banks then take those inputs and use them to earn income by "selling"
loans and other investments and services. Alternatively, one might view the
receiving of deposits as a form of services provided by the bank and thus as
one of the banks outputs.
Until
recently, the deposit activity of a bank was essentially non-transferable, and
many separate banking offices were needed to service adequately a large urban
area full of depositors and borrowers. But the deposit services of a bank may
soon become very transferable indeed. We see already more and more banking
machines acting as robot tellers; banking by phone is developing, and banking
via home computer is in the offing.
So
depositors who now have to travel to a bank, or use the mails, will soon find
that the banks services travel instantly to them. With the proliferation
of electronic transactions and home computer terminals, we can foresee that the
customer service area of a single banking office will no longer be confined to
a neighborhood, and that presumably far fewer bank locations will be
needed.
Locational
relations among different activities likewise are subject to important
alteration when the transferability of information is greatly enhanced, as is
now happening. An example of this is firms that provide troubleshooting and
repair service to users of complex equipment. The easy and quick availability
of such services has been an important factor to many firms. While maintenance
specialists can be dispatched some distance to attend to problems, speed is of
the essence. Close proximity to the suppliers of the service has meant speedy
attention, less down time, more regularity of production, and therefore lower
operating costs. There is even a saving in capital costs as fewer machines are
needed to ensure a given rate of production and as goods spend less time in the
production process.
But in
recent years some highly sophisticated "smart" machines that incorporate
computer systems to monitor performance have also been endowed with a capacity
for self-diagnosis. When a problem occurs, such a machine is capable of
immediately signaling the probable nature and extent of the difficulty. This
information can be relayed by wire to central service facilities that are
equipped to interpret it and to recommend or provide maintenance or repair
procedures entailing a minimum of delay. Thus the integrated character of
industries can take on new forms. The repair facility now has greater
flexibility of location as the transfer costs on its output are reduced and the
firm operating the complex equipment faces lower transfer costs on an important
service input. Both are able to respond more freely to other locational
factors.
The
communications revolution promises likewise to have significant effects on
locational relationships among establishments of the same firm. In a study of
branch plants in four states over the period 19671976, Rodney A. Erickson
and Thomas R. Leinbach found that the size of branch plants is positively
related to their distance from corporate headquarters. The farther away from
headquarters, the larger the branch tends to be.13
This
relationship reflects the handicap that distance has always imposed on a
firms ability to centralize decision-making and at the same time to keep
in touch with and direct the operations of scattered field offices or branches.
Branches have had to become more autonomous and assume more decision-making
functions as their distance from headquarters increases. It may be surmised
that current and foreseeable advances in data processing and transmission will
alter this relationship. Effective centralized coordination and control at long
distances should become more feasible. Specialized operations of large firms
may be oriented more closely to their specific markets without sacrificing
adequate contact with headquarters.
3.6 Summary
This
chapter explores (1) the ways in which transfer costs in the real world are not simply proportional to crow-flight distance as was assumed in Chapter 2, and (2) the locational significance of
such departures from a uniform transfer surface.
Transfer
operations almost always involve a large element of fixed costs. Consequently,
there are important scale economies related to route traffic volume, terminal
volume, and size of individual movement unit and consignment. There is also
wide leeway for transfer agencies in apportioning their fixed costs over
various classes of services so as to improve capacity utilization, meet
competition, and increase profits.
Transfer
services by any one mode are generally confined to a limited network of routes
and service points, determined by variations in terrain and scale economies.
Transfer costs by any one mode also generally rise less than proportionally
with longer distancemainly because of terminal cost, but also often
because of lower line-haul cost per mile on longer hauls.
The pattern
of rates charged by transfer agencies is even less like a uniform transfer
surface than is the pattern of transfer costs. There is normally rate
discrimination in favor of larger-volume services, longer hauls, routes and
types of services where interagency or intermodal competition exists, and goods
of low value relative to their weight or bulk. Further, where the demand for
transfer between two points is not the same in both directions and returnable
vehicles are used, cheaper back-haul rates in the direction of lower transfer
demand are likely.
Other
important characteristics of transport rates have been noted. Rate structures
are generally simplified by setting uniform rates for categories of services
and ranges of distance, shipment size, and so forth, rather than setting a
separate rate for each service. Additionally, time costs are an important part
of total transfer cost for high-valued or perishable shipments and especially
for transfer of people and information.
Each of
these departures from the uniform transfer surface has an effect on locational
preferences. We have also recognized that both long-haul economies and the
restriction of transfer to limited systems of routes and service points enhance
the locational advantages of markets, input sources, and route junctions,
including modal interchange points.
Together
with the theoretical basis developed in Chapter 2,
these considerations provide a framework for examining the locational
implications of changes in our economy that alter the structure of transfer
costs.
TECHNICAL TERMS INTRODUCED IN THIS CHAPTER
Transfer
mode |
Back-haul
rates |
Transfer service
points |
Rate blocks or
distance zones |
Long-haul
economies |
Local optimum
location |
Terminal operations
and costs |
Isoprofit
lines |
Line-haul or movement
costs |
modal interchange
locations |
Transfer
agency |
Transshipment
locations |
Gradient |
|
SELECTED READINGS
Benjamin Chinitz, Freight and the Metro polls, a report of the New York Metropolitan
Region Study (Cambridge, Mass.: Harvard University Press, for the Regional Plan
Association, 1960).
Benjamin Chinitz, "The
Effect of Transportation Forms on Regional Economic Growth," Traffic
Quarterly, 14 (1960), 129-142. Reprinted in Gerald J. Karaska and David F.
Bramhall, Locational Analysis for Manufacturing (Cambridge, Mass.: MIT
Press, 1969), pp. 83-96.
John R. Meyer, M. J. Peck,
J. Stenason, and C. Zwick, The Economics of Competition in the
Transportation Industries (Cambridge, Mass.: Harvard University Press,
1959).
Hebert Mohring, Transportation Economics (Cambridge, Mass.: Ballinger, 1976).
APPENDIX 3-1
Rate Discrimination by a
Transfer Monopolist
Assume that a good is to be
shipped to various markets from a single point of origin. At each market the
quantity sold (and consequently the quantity shipped to that market) will
be
q =a b(p + r)
Where p is the price at the
point of origin (the same for all markets) and r is the transfer
charge.
The transfer agencys
cost of carrying the good to a market x miles away from the point of origin is (g + tx) per ton, where g is terminal cost and t is line-haul
cost per mile.
On shipments to a market at
a distance x, therefore, the transfer agency will make a net return
of
Z =(a bp br)(r g tx)
Differentiating,
dZ / dr=a bp 2br + bg + btx
and the most profitable
rate to charge (r*) is calculated as follows:
a bp
2br* + bg + btx=0
r*=(a
bp + b) / 2b + tx / 2
The ideal tariff will be a
flat charge equal to
1/2 [(a / b) + g p]
plus half the line-haul
cost for each mile of haul.
ENDNOTES
1. In regard to trucking cost, "The ICC has consistently reported
that line-haul costs decline with distance shipped. However, this is
largely a spurious correlation, reflecting the fact that size of shipment and
length of haul are correlated, and not attributable, as the ICC implies,
to some operating characteristics that makes line-haul ton-mile costs
substantially less on a two-hundred-mile than on a one-hundred-mile trip Total
unit costs do decline with distance, however, because of the distribution of
terminal expense over a large number of ton miles." John R. Meyer and others, The Economies of Competition in the Transportation Industries (Cambridge, Mass.: Harvard University Press, 1959), p. 93.
2. Illustrative of the indirect "inventory economies" of faster
transport, United Air Lines in 1961 suggested that "UAL Air Freight can be
profitable when the added cost of shipping by air freight is less than
9½% of the cost value of the goods involved." This conclusion is based
on the estimate that air freight shipment can, on the average, reduce
warehousing requirements by about 40% and inventory requirements by about 20%.
For the average product shipped, warehousing charges run about 12% of cost
value, and inventory charges about 25%; thus the total saving by air freight
amounts to a little more than 9½% of the cost value of the goods. It is
easy to see that the appeal of air freight is likely to be higher for goods wit
high value per pound. Note also that the savings associated with air freight is
sensitive to interest rates. When higher interest rates prevail, reductions in
inventories and in delays associated with warehousing can mean considerable
savings to customers who use this mode of transfer.
3. 0n the private and social evaluation of personal travel time, see
Colin Clark, Population and Land Use (London: Macmillan, 1969; New York:
St. Martins Press, 1969), pp. 377-379; Albert Rees and George P. Shultz, Workers and Wages in an Urban Labor Market (Chicago: University of
Chicago Press, 1970); and Thomas Domencich and Daniel McFadden, Urban Travel
Demand (New York: North-Holland, 1975). The consensus seems to be that
people rate the disutility of travel to work at only about one-third to
one-half of their earnings rate; but that there are some additional costs of
longer commuting time which are borne by the employer (wage premiums, increased
absenteeism and tardiness, and lowered productivity through fatigue) and which
might be of similar order of magnitude to the costs borne by commuters
themselves. Some studies have estimated the valuation of private costs to be
substantially lower than one-third of the earnings rate. See William C.
Wheaton, "Income and Urban Residence: An Analysis of Consumer Demand for
Location." American Economic Review 67, 4 (September 1977), 620-631, for
references to several of these studies.
4. The "forks" mentioned in Figure 3-4 are
defined as three-branch (Y) junctions. Readers may wish to amuse themselves by
constructing the four additional kinds of networks that are possible with no
more than three ends and no more than three forks: no ends, two forks; one end,
three forks; two ends, two forks; and three ends, three forks. The sum of the
number of forks and ends is always even.
5. See Robert Dorfman, "Mathematical or Linear
Programming: A Nonmathematical Exposition," American Economic Review,
43, 5 (December 1953), 797-825.
6. This conclusion throws some additional light on the significance
of the shape of the locational polygon where the route constraint is ignored
(see Figures 2-3 and 2-4 in
the previous chapter). In Figure 2-4, the locational
triangle was compressed so that the obtuse corner was the optimum transfer
location. As the triangle is squeezed, it obviously approaches closer and
closer to the configuration of a single line, with the obtuse corner becoming
the intermediate point on the line, like point B in System 1 of Figure 3-4.
7. We are assuming that all inputs and outputs other than those
specifically mentioned are ubiquitous, so that processing costs would be the
same at all locations. The activity is assumed to be wholly
transfer-oriented.
8. Details on some of the issues raised in the remainder of this
section may be fond in Frank Giarratani and Charles F. Socher, "The Pattern of
Industrial Location and Rising Energy Prices," Atlantic Economic Journal 5, 1 (March 1977), 48-55. For a theoretical discussion of some related topics,
see Noboru Sakashita, "The Location Theory of Firm Revisited: Impacts of Rising
Energy Prices," Regional Science and Urban Economics, 10, 3 (August
1980), 423-428.
9. Commodities with a high value-to-weight ratio can more easily pass
along to their customers the high ton-mile charges associated with truck
transport.
10. Ernst R. Berndt and David O. Wood, "Technology,
Prices, and the Derived Demand for Energy," Review of Economics and
Statistics 57, 3 (August 1975), 259-268.
11. See William H. Miernyk, Frank Giarratani, and
Charles Socher, Regional Impacts of Rising Energy Prices (Cambridge,
Mass.: Ballinger, 1978), pp. 57-76.
12. Not all energy-producing regions can be expected to
share equally in these advantages. For example, some coal-producing regions
have been severely affected by restrictions placed on the use of coal with high
sulfur content because of environmental concerns.
13. Rodney A. Erickson and Thomas R. Leinbach,
"Characteristics of Branch Plants Attracted to Nonmetropolitan Areas," in
Richard E. Lonsdale and H. L. Seyler (eds.), Nonmetropolitan
Industrialization (Washington, D.C.: V. H. Winston, 1979), p.
68.
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