Sax, Die Verkehrsmittel in Volks- und Staatswirtschaft (1918)

Sax’s treatise renews transport theory by extending it beyond railways to all organized means of overcoming distance: roads, posts, telegraphy, telephony, motor traffic, power transmission, and aviation. Its object is not technique in isolation, but the economic function of distance-conquering institutions within production, exchange, administration, and cultural life. Transport is defined at this general level as

die Überwindung der räumlichen Entfernungen im gesellschaftlichen Zweckleben.

English translation: the overcoming of spatial distances in the purposive social life.

This breadth lets Sax treat transport services as a pervasive category of cost. Moving goods, persons, messages, or energy consumes resources and enters productive or consumptive accounts. Progress is therefore not mere acceleration, but the cheapening, regularization, and improvement of service relative to social purpose. Lower transport costs enlarge markets, intensify demand, widen sales areas, and promote spatial price equalization. Sax’s striking formula is that market reach expands not simply in proportion to transportability, but as an area:

Die Absatzfähigkeit (somit der Markt) der Güter wächst im quadratischen Verhältnisse mit der Transportfähigkeit durch die Verkehrsentwicklung.

English translation: The marketability (and hence the market) of goods grows in quadratic proportion to their transportability as transport develops.

The point is historical as well as theoretical. Costly long-distance traffic had always existed for high-value goods; modern transport makes low-value mass goods mobile and draws local economies into national and world markets. Agriculture is released from simple proximity to towns and reorganized around natural productivity, while industry is freed from older constraints of raw material and market location. Large-scale production, specialization, and spatial separation of stages become possible. Transport thus becomes a force reshaping prices, rents, industrial location, and the territorial division of labor.

Sax’s analytical core is an “economic anatomy” of transport: route, vehicle or apparatus, and motive force. Modern transport requires heavy fixed capital and relatively little raw-material transformation, so it follows distinctive economic laws. Capacity must correspond to traffic density; duplicate facilities waste capital; routes follow economic rather than geometrical shortest paths; superior modes absorb traffic from inferior ones while creating feeder systems. The decisive cost proposition is that transport expenses are mainly common costs:

Der Verkehrsaufwand besteht im wesentlichen in Gemeinkosten.

English translation: The expenditure on transport consists essentially of overhead (fixed) costs.

Because fixed costs are spread over volume, tariffs may create the traffic that lowers unit cost. Sax therefore reverses ordinary cost-price reasoning:

Im Verkehrswesen bestimmen nicht die Kosten die Preise, sondern die Preise die Kosten.

English translation: In the transport sector it is not the costs that determine the prices, but the prices that determine the costs.

This reversal grounds his tariff theory. Sax rejects simplified cost-plus pricing, yet also refuses pure value pricing. Passenger classes, child fares, goods classifications, distance scales, zones, and differential rates arise from the interaction of cost, traffic density, capacity to pay, market expansion, and utilization of fixed plant. Cost remains a lower bound and comparative measure, but rational tariffs must also draw out traffic and serve public purposes.

The same structure explains why transport becomes an object of Gemeinwirtschaft, or collective economy. Sax does not deny private initiative; private firms may pioneer new techniques. But network effects, monopoly tendencies, indirect social benefits, and the need for unified planning make unregulated competition unreliable. A technically superior mode possesses, within its sphere, a natural monopoly:

Jedes Verkehrsmittel hat einem minder vollkommenen gegenüber in seinem Verkehrsgebiete ein tatsächliches oder natürliches Monopol.

English translation: Every means of transport has, in relation to a less perfect one, an actual or natural monopoly within its own transport region.

Competing duplicate networks squander fixed capital and tend toward pools, cartels, mergers, or ruin. Public authority must therefore secure access, equality, technical unity, tariff supervision, and territorial coordination, whether through regulation, concession, or direct operation. Sax’s “state-economic profitability” can justify lines that are privately unprofitable because of military, administrative, developmental, or wider social gains, though he warns against using this as an empty pretext.