Transportation: Roads, Rail, Ports, Aviation

The Shape of the Freight World

A useful first question: how much of the world's physical stuff moves by which mode?

In tonne-kilometres (a tonne of goods moved one kilometre):

Shipping (sea)      ~70% of global tonne-km (long distances, bulk goods)
Rail                ~10%
Road                ~15%
Pipelines           ~5%
Aviation            <0.5%

Shipping dominates because most long-distance international freight goes by sea. Per tonne-km, it's by far the cheapest and lowest-carbon mode. Aviation is the opposite: tiny in volume, dominant in cost per tonne.

For people:

Walking / cycling   still the largest modal share globally
Private cars        dominant in developed countries
Buses               largest share in many developing countries
Rail                regional dominance (Japan, Europe, China urban)
Aviation            long distance (under 1% of all travel, >10% of transport emissions)

Modes are optimised for different distances, costs, and cargo types. Understanding when each wins is most of transport literacy.

Roads

Road networks are the largest physical infrastructure humans build. They connect everywhere to everywhere else, enable last-mile delivery, and absorb most short-distance travel.

Hierarchy

Roads have a hierarchy by design speed and access:

Local streets           low speed, frequent access (driveways, side streets)
Collector roads         moderate speed, feed arterials (local connectors)
Arterials               higher speed, fewer intersections (main roads)
Expressways / highways  high speed, controlled access (freeways, motorways)

Traffic engineers design intersections and capacities at each level. Failures in one level (an arterial at capacity, a highway over-reliant) cause cascading delays.

Capacity math, roughly

• A single lane of urban street: ~600-1,000 vehicles per hour
• A highway lane: ~2,000 vehicles per hour
• Beyond that, traffic slows, and actual throughput (vehicles × speed) drops

This is why adding lanes often fails to relieve congestion: the extra capacity fills with induced demand (people who now drive because the road is faster), and the final state has more traffic at similar speeds.

Cars

Roads (as most Americans know them) carry cars. Cars move people well for some use cases, poorly for others:

• Good: flexible routes, private space, door-to-door, works with dispersed destinations
• Bad: parking (20-30% of urban land in car-dominated cities), congestion, deaths (~40,000/year in US), noise, emissions
• Cost: roughly $0.50-$1.00 per mile fully loaded in the US (fuel, insurance, depreciation, maintenance), plus road subsidy

The costs are partly hidden from the driver (roads funded from general taxes in many places, parking included in rent and retail prices). This is part of why cars win in competition with transit: their external costs aren't in the price.

Trucking

Most freight in developed countries, in tonne-km at intercity level, moves by truck. Trucks are flexible (direct to the dock), but per tonne-km more expensive and more polluting than rail.

The US model: long-haul trucks between distribution hubs, smaller trucks for last mile. Europe does somewhat more rail freight and is gradually shifting more; full electrification of short-distance trucks is viable; long-haul electric trucks are emerging; hydrogen and fuel cells are one candidate.

Rail

Trains are the oldest modern transport. They're also remarkably efficient per unit moved.

Why rail efficiency

A steel wheel on a steel rail has very low rolling resistance. A train can move thousands of tonnes with a fraction of the energy a fleet of trucks would need. Electrified rail, in particular, is extremely efficient.

Passenger rail

Shapes:

• High-speed rail (200+ km/h): Japan (Shinkansen), China (enormous network), Europe (TGV, ICE, AVE), limited in US. Effective for 200-1000 km trips; beats flying door-to-door on many routes
• Conventional intercity rail: moderate speed, many countries
• Commuter rail: daily service into major cities
• Metro / subway: urban rapid transit, high capacity in core urban areas
• Light rail / trams: lower capacity, lower cost urban transit

Freight rail

Long trains of bulk goods (coal, grain, containers, chemicals). The US has enormous freight rail (mostly private, mostly bulk); Europe has less because road has been favoured and rail networks are smaller-gauge.

Container-on-flatcar (intermodal) moves containers between ports and inland destinations.

Rail's advantages and costs

• Efficient per tonne-km or person-km
• Lower emissions especially if electrified
• Dense capacity on a single track corridor
• High capital cost to build and maintain
• Inflexible: the route is the route
• Network effects: more valuable as the network grows

Countries that have invested in rail (Japan, Switzerland, much of Europe, China recently) get enormous value from it. Countries that haven't (US for passenger rail, much of the developing world) face large catch-up costs.

Ports and Shipping

Ninety percent of international trade by volume moves through ports. Understanding shipping is understanding global commerce.

Containers

The standard shipping container (20-foot equivalent unit, TEU) revolutionised shipping from the 1960s onward. Before containers:

• Goods loaded piece by piece by longshoremen
• Days to load or unload a ship
• High labour costs, frequent damage, theft

After containers:

• Standardised, stackable, intermodal (ship → train → truck with the same box)
• Hours to load and unload
• Enormous throughput
• Global supply chains become feasible

Modern container ships carry 18,000-24,000 TEU. A single voyage moves more cargo than a 19th-century port handled in a year.

Bulk shipping

Separate economy from containers:

• Tankers: oil, gas, chemicals
• Bulk carriers: grain, ore, coal, other dry bulk
• Sized to specific routes (Panamax, Suezmax, VLCC for oil, etc.)

Chokepoints

Global shipping flows through a small number of chokepoints. Disruption at any of them affects world trade.

• Strait of Hormuz: ~20% of world oil
• Strait of Malacca: Asia-Europe trade
• Suez Canal: Asia-Europe, ~12% of world trade (Ever Given grounding in 2021 showed the fragility)
• Panama Canal: Pacific-Atlantic (drought in 2024 reduced capacity)
• Bab el-Mandeb: Red Sea entrance, Houthi attacks in 2024+

Chokepoints are one of the structural fragilities of modern supply chains (chapter 10).

Ports

A modern container port is one of the most engineered places on Earth:

• Deep berths to handle enormous ships
• Gantry cranes to unload at 30-40 moves per hour
• Dense container yards
• Rail and truck connections
• Automated or semi-automated systems

The largest ports (Shanghai, Singapore, Ningbo, Shenzhen, Guangzhou) handle 25-40 million TEU per year each. That's staggering volume.

Aviation

Aviation moves people fast and goods when urgency matters. It's expensive per tonne-km and CO2-intensive.

Hub and spoke

Most airline networks use a hub-and-spoke model: feed local flights into a hub city, where passengers transfer to long-haul flights to other hubs.

• Pros: few routes needed (N cities connect through sqrt(N) hubs), high load factors
• Cons: total travel time worse than point-to-point, hub delays cascade

Budget airlines (Southwest, Ryanair, EasyJet) use more point-to-point routes on specific corridors. Both models exist in healthy markets.

Aircraft efficiency

Modern aircraft are more efficient than earlier generations, but aviation's per-passenger fuel use is fundamentally high because of:

• Weight lifted against gravity
• Drag at high speeds
• Kerosene energy density required for range

Per passenger-km, aviation is roughly 2-5x the CO2 of a car (with typical occupancy), 10-20x the CO2 of a train.

Decarbonising aviation is one of the hardest problems of the energy transition. Batteries are too heavy for long-haul flight. Sustainable aviation fuel (SAF) and hydrogen are candidates; neither is deployed widely yet. Expect aviation to be one of the last sectors to fully transition.

Freight aviation

Most air freight is high-value or urgent: electronics, pharmaceuticals, perishables, spares for broken industrial equipment. About 1% of freight by weight, over 30% by value.

Pipelines

Pipelines move liquids and gases over long distances. The most efficient way to move oil, gas, or water over land.

• Oil pipelines: crude from fields to refineries, products from refineries to distribution
• Gas pipelines: natural gas from wells to markets, plus urban distribution networks
• Water: long-distance transport (California Aqueduct, parts of the Middle East)

Pipelines are underrated; they move vast amounts of material quietly. Failures (leaks, ruptures, explosions) can be dramatic but are rare per unit of flow.

Last-Mile Delivery

A modern attention-getter. The rise of e-commerce made last-mile delivery (from local depot to doorstep) a major industry.

• Costs per package are disproportionate to the trunk shipping
• Urban density makes it efficient per stop; sprawl makes it hard
• Electric vans and cargo bikes are increasingly used in dense cities
• Drones have been hyped for years; real deployment is still marginal

This is an interesting layer because it interacts with everything: e-commerce patterns, urban design, labour, pollution, and road usage.

The Transport Energy Mix

A useful summary:

Passenger cars            mostly petroleum, rapidly electrifying
Trucks                    mostly diesel; electrification beginning
Rail                      significantly electrified where infrastructure exists
Ships                     heavy fuel oil (bunker fuel); regulations tightening
Aviation                  kerosene; decarbonisation is slow
Pipelines                 electric (for pumping); mostly decarbonisable via grid

Transport overall is about 25-30% of global CO2 emissions. The mix is shifting slowly but visibly: EVs are growing fast; shipping and aviation are structurally harder.

Common Pitfalls

"High-speed rail doesn't work in [my country]." In most cases, it does for specific corridors at specific distances. It doesn't work for all of a country. The all-or-nothing framing is usually wrong

"Cars are freedom." Cars are useful; the full cost (land, deaths, environment, infrastructure) is larger than most drivers pay. A literacy move: notice the subsidies when you hear arguments for or against transport modes

"Electric vehicles solve everything." They solve some things (local pollution, operational emissions). They don't solve road safety, congestion, land use. Transport mode mix still matters

"Just move everything by rail." Rail is great for specific flows. Flexibility and last-mile still require roads. The optimum is a mix, not substitution

"Aviation is evil." Aviation is a specific combination of high per-unit emissions and enormous value (connecting distant places, moving urgent goods). The policy question is how much aviation, priced how, not whether to ban it

Next Steps

Continue to 07-telecom-and-internet.md for the physical layer under every digital service.