| By Edward N. Luttwak

The classic cases of strategic infrastructure investments are of course the Roman road network that started with the Appian way and China’s 1,794-kilometer “Grand Canal” from the Yellow to the Yangtze rivers. Both date back to the fourth century BCE, though Roman road-building did not persist beyond the third century CE, while China’s Grand Canal was only completed in the seventh century. In both cases, moreover, the initial and persistent motivation was military while the consequences were economic, cultural and political, resulting in powerful unification processes in both cases. Just as striking as these symmetries is the historical rarity of such highly functional endeavors—China’s was always a grain-moving system — as opposed to the ubiquity of gigantic ceremonial structures from the pyramids of Mexico to the pyramids of Egypt, and of stupendous palatial cities from Central America to Southeast Asia.

In modern times, the construction of palatial complexes has persisted much more vigorously than the construction of major functional infrastructures. Against the Panama and Suez canals, there are dozens of synthetic capital cities. That is understandable because palatial capitals can more easily generate subjective political benefits than functional infrastructures can generate objective economic benefits. Grand would-be functional projects that promise increased efficiencies can fail economically as well as commercially even in the most promising circumstances, as in the case of the Channel Tunnel where the costs clearly exceeded the benefits. Even if such macro-projects do not fail economically in terms of opportunity costs, or commercially, because both markets and regulators allow profitable tariffs, efficiency gains are almost always bounded by pre-existing alternatives: ferries before bridges, surface routes before tunnels.

Major infrastructure projects that open entirely new routes are something else entirely. They can still fail economically in terms of opportunity costs either because of excessive costs or insufficient demand (as in the case of northern Norway’s perpetually empty four-lane highways) but their political importance can be very significant, even momentous.

A potential rather than actual example is perhaps the world's most obviously missing major infrastructure: a trans-Caspian bridge. Five Central Asian states are land-locked, while two of them (Kazakhstan and Turkmenistan) only have access to the landlocked Caspian Sea. The resulting severe constraints on their economic development are notably costly, sometimes to an extreme extent. Any item wider than the maximum allowed by the Russian railway T-profile limit of 3.75 meters can only be delivered by air or road. Air delivery is never cheap, often simply unaffordable, and in any case is subject to an absolute weight limit of 150 tons (with the Antonov 124, still the largest series of cargo aircraft). Road delivery is slow, winding from an eastern Caspian port, itself reached from oceanic routes via the Black Sea, then up the Volga-Don canal and down the Volga to the Caspian. Given the great importance of extractive industries for the region's economies and their routine need of very large items of equipment that exceed the 3.75 meter Russian width constraint, the Black Sea-Caspian sea route is necessarily very important. It is also circuitous and entirely unavailable during the winter months when the Volga-Don canal freezes solidly, an interruption that regularly delays major projects for months at a time.

But there is an infrastructure solution to this logistic predicament that powerfully limits the development of five countries: a 200-kilometer bridge across the Caspian from Azerbaijan's Baku to Turkmenistan's Ufra. At Ufra, there are both road and rail links to nearby Kazakhstan, whose own railways already connect the Caspian shore with the Dostik-Alashankou road and rail crossing into China. At the other end, Baku is connected by both road and rail to Georgia's large-capacity Black Sea port of Poti, from which the world's oceans are reached via the Dardanelles. A trans-Caspian bridge with both rail lines and roadways would, therefore, transform the landlocked condition of Central Asia and Kazakhstan, a revolutionary change psychologically as well as in strictly material ways.

Moreover, this is an eminently viable project, technically and commercially. Because the Caspian seabed has been extensively drilled for oil and gas, it is quite certain that standard offshore platform towers to support pre-cast concrete modules could both reach solid ground 100 meters below the water and elevate the bridge 100 meters above it, in order to preclude any possible Russian or Iranian navigation claims. Commercially, the project would generate multiple revenues streams, from the rail delivery of shipping containers from China, to less important road transit fees, to both oil and gas pipeline revenues (large-diameter, under-bridge pipelines would naturally fit within the pre-cast concrete bridge modules), making it feasible to pay for the $20 billion or so construction costs largely or entirely with project finance.

But there is no such easy solution for the Russian government's inevitable opposition — a trans-Caspian bridge would emancipate the region from Russian logistic control. That explains why a trans-Caspian bridge, the world's most obvious missing major infrastructure, has not been built, or even proposed — except here.

Edward N. Luttwak is a former Senior Associate at the Center for Strategic and International Studies, a government consultant, and author.

This article is part of our Big Questions Series.