🚢 Dire Straits

Modern logistics systems are highly automated and efficient. But they are also prisoners of geography. And when that geography is compromised, the effects are huge.

Good day my good friend.

This week, I am providing a sequel to a post that I wrote last year. Building upon some work I did some years ago for the Development, Concepts, and Doctrine Centre of the Ministry of Defence (now called Defence Futures), the original post showed why the American Government’s advances towards Greenland made strategic sense. Now, this update shows the scale of the blunder they made with Iran.

I should probably stress that this is my view only, and I have not been active in the defence space for some time now. If you want some more informed analysis of the situation in the Persian Gulf, I highly recommend War on the Rocks and the Institute for the Study of War. Both of whom put out excellent analysis and commentary.

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While the likes of Amazon and Teemu give the impression of a seamless and integrated global logistics system, there is a worrying geographical reality at the centre of it. Global trade is highly concentrated into a handful of narrow waterways and canals. Despite the oceans covering over 70% of the Earth’s surface, the reality of commercial shipping (driven by our demand to have things to us as quickly and cheaply as possible) means that most trade takes place on a few key corridors. This, inevitably, results in choke-points.

Most people working in international logistics can probably tell you what these are off the top of their head. But just in case you don’t know, some of the most important include:

• The Strait of Malacca between Malaysia, Indonesia, and Singapore;

• The Strait of Bab el-Mandeb between the Red Sea and the Gulf of Aden;

• The Bosporus between the Mediterranean and Black Seas;

• The Suez and Panama Canals;

• The Strait of Dover in the English Channel;

• The Strait of Gibraltar between the Mediterranean Sea and Atlantic Ocean;

• The Strait of Hormuz between the Persian Gulf and the Gulf of Oman.

Others might also add the South China Sea and East China Sea to this list.

Because global trade gets constrained at these corridors, there is a distinct, calculated method in the madness of global geopolitics and military strategy when it comes to these areas. If you control the Strait or the Canal, you can apply a vice-like grip on the global economy.

The global transport system is heavily reliant on maritime transit, with over 80 per cent of the volume of international trade in goods carried by sea. But these vessels have to travel through these chokepoints. They are narrow, and in some places have shallow water which constrains the shipping lanes even further. When combined with sometimes volatile states on the adjacent shores, this presents a major risk to shipping operators.

The physical environment of a maritime chokepoint restricts the speed and manoeuvrability of massive commercial vessels. In the open ocean, a modern supertanker or ultra-large container vessel has infinite avenues of evasion and manoeuvre. Within a strait, its path is highly predictable, strictly regulated by the depth of the waters and traffic management systems, and easily observable from the coast.

Environmentally, these waters are treacherous. Shifting shoals, severe weather patterns, and narrow navigable channels mean that the margin for error can often be very small. For instance, the Dover Strait - which I am sure many of my readers will know well - is 20 miles across at its narrowest point. That sounds like a lot, but this is a strait where the weather can turn in an instant, has strong tides and shifting sand banks, is used by over 400 ships a day passing through, and is also crossed by numerous cross-channel ferries. All ships which can not exactly stop on a sixpence if one gets stranded.

Yet, physical hazards are only part of the problem. The biggest vulnerability is geopolitical. Because these straits are flanked by landmasses, any state or non-state entity that controls the adjacent shores possesses the capability to project hard power over the water. As such, local disputes can instantly be internationalised, forcing global powers to intervene in regional conflicts to protect their economic lifelines.

The United Nations Conference on Trade and Development (UNCTAD) routinely highlights the fragility of these systems. In their Review of Maritime Transport 2023, UNCTAD emphasises that shipping continues to navigate complex post-pandemic trends, shifting trading patterns, and unprecedented disruptions. When a chokepoint is threatened, the immediate reaction of the global shipping industry is to reroute vessels to avoid the area of risk. In some instances, like a war breaking out, their insurers will tell them that if they sail into these waters they will not cover them should something happen.

But avoiding the area is a remedy that inflicts its own severe economic damage. For instance, re-routing from the Suez Canal to the Cape of Good Hope, such as when the Ever Given ran aground, adds thousands of nautical miles to a journey. This means higher fuel costs, severe delays, and a cascading shortage of available ships and shipping containers worldwide. These costs are immediately passed on to consumers, driving global inflation and threatening the stability of developing economies that rely on affordable imports.

And so we come to current situation in the Persian Gulf. The Strait of Hormuz, a slender passage between the Persian Gulf and the Gulf of Oman, has 20 million barrels of oil - around 25% of world oil supplies - passing through each day. To block the Strait of Hormuz is to cut the umbilical cord of global energy supplies. A sustained closure of the Strait is resulting in energy prices spiking. That means higher inflation and a global recession. The mere threat of closure by regional actors is often sufficient to influence market speculation and extract diplomatic concessions.

I will not comment on the relative merits of current American, Israeli, and Iranian action in the area. But I will say this. Because of its proximity to the Strait of Hormuz, blocking the strait is one of the few trump cards Iran has. They don’t even have to mine the strait either - just the risk of it is resulting in the likes of Lloyd’s Register to say to shipping companies that if they sail through their premiums will be substantial. Meanwhile convoys protected by naval vessels are untested in a time of drone warfare.

The most frustrating thing is that this kind of outcome could be foreseen by any military planner with a mote of common sense, or even just 5 minutes thinking time. We know this because military planners across the world know of the strategic risks of narrow maritime straits, and the most competent have planned for them.

The method in the madness of deploying vast military and diplomatic resources to secure straits is a simple one. Doing so gives huge geopolitical leverage. It is a mechanism to hold the world hostage or to prevent an adversary from doing the same.

This dynamic has subtly been driving military expansion and infrastructure development globally. A premier example of this is China’s strategic calculus regarding the Strait of Malacca. The vast majority of China’s energy imports from the Middle East and Africa, alongside its massive export volume to Europe, must pass through this narrow, congested waterway between Indonesia, Malaysia, and Singapore. In China this is known as the Malacca Dilemma - the profound fear that in the event of a conflict, adversarial naval powers could blockade the strait and effectively starve the Chinese economy of energy resources and trade.

This vulnerability has driven Beijing to take drastic corrective measures. The rapid modernisation and expansion of the People’s Liberation Army Navy (PLAN) into a formidable naval force is, in part, designed to project power towards the Malacca Straits and secure its sea lines of communication. Concurrently, China’s Belt and Road Initiative (BRI) and the construction of overland pipelines through Myanmar and Pakistan are explicitly designed to bypass the strait. This is an illustration of how the vulnerability of a single transport system can dictate the grand strategy of a superpower.

You also don’t need a navy to exercise power over these waterways. Coastal states are increasingly utilising coast guards, maritime militias, and paramilitary actors to assert control over contested waters without crossing the threshold of conventional armed conflict. A good example is Houthi rebels operating in Yemen. Nominally supported by Iran, this band of rebels fired on ships transiting the Red Sea in 2025, forcing the USA and Oman to negotiate a ceasefire with them. This shows that states (in this case Iran) can effectively restrict maritime access and exert immense political pressure while maintaining plausible deniability.

Given the catastrophic consequences of a severed maritime chokepoint, military planning must revolve heavily around the capability to secure, defend, bypass, or contest these environments. Traditional naval strategy has historically been defined by the sweeping doctrines of ‘sea control’ and ‘power projection’. However, defending a strait is fundamentally different—and often far more complex—than fighting a fleet in the open ocean.

Photo by Venti Views on Unsplash

For a military planner tasked with ensuring the freedom of navigation through a chokepoint, this can that naval forces cannot simply escort civilian vessels safely. To neutralise the threat, naval and air forces must be prepared to strike inland targets—such as missile launchers hidden in complex terrain or mobile radar stations. This changes the nature of the mission, and risks escalating into a broader conflict involving strikes on a sovereign nation’s mainland.

The vulnerability of maritime straits also makes them immensely attractive to non-state actors, terrorist organisations, and proxy militias. These groups recognise that they do not need a multi-billion-pound navy to disrupt global trade.

Recent conflicts around the Bab el-Mandeb strait serve as a blueprint for future military planning. Operating from coastal sanctuaries, relatively lightly armed militant groups have successfully disrupted one of the world’s most vital shipping corridors. They employ cheap, commercially available drone technology, repurposed anti-ship ballistic missiles, and swarms of small, explosive-laden fast-attack boats. British and American naval vessels now have to routinely patrol these waters.

Military planners are forced to grapple with a scenario where a state-of-the-art interceptor missile, costing millions of pounds and fired from a billion-pound air defence destroyer, is required to defeat a loitering munition that costs only a few thousand pounds to manufacture. Needless to say that quite often, that is against the planning assumptions of even the finest military minds in the world.

While the threats on the surface and in the air are highly visible and immediately terrifying, below the surface the challenges are equally steep. The physical characteristics of maritime chokepoints like shallow depths and unpredictable tidal currents make anti-submarine warfare exceptionally difficult.

Conventional, diesel-electric submarines operated by coastal states are a planner’s nightmare in these environments. Running on silent battery power, a small submarine can sit undetected on the seabed within a strait, its acoustic signature entirely masked by the deafening cacophony of passing civilian supertankers and bulk carriers. From this hidden vantage point, it can launch torpedoes or deploy advanced, autonomous naval mines.

Naval mines remain one of the most cost-effective methods of denying access to a strait. A single, cheap contact mine, or a more advanced influence mine resting on the seabed, can instantly close a multi-billion-pound waterway. It is possible to counter-act this through deployment of autonomous underwater vehicles (AUVs), unmanned surface vessels (USVs), and advanced seabed surveillance systems. But this is laborious, dangerous work, and all the while the tankers pile up on both sides of the strait.

Western military planning, particularly for nations like the United Kingdom and its NATO allies, must also contend with the inescapable tyranny of distance. Most of the critical maritime chokepoints are located thousands of miles from home ports and industrial bases. Despite what the shouting in the House of Commons might indicate, putting a ship to sea is not something that takes 10 minutes. And maintaining a continuous naval presence in the Indo-Pacific, the Persian Gulf, or the Red Sea requires an extraordinary logistical undertaking.

This is just to put a single vessel to sea. In reality, you aircraft carriers with their associated crews, amphibious readiness groups, and ships whose sole purpose is to escort merchant shipping. Not just this, but you need support ships, maintenance crews, and open supply lines with ships on constant rotation. If that was not enough, you need a forward base where you can refuel and restock ships, rotate crews, and provide support, all negotiated through diplomatic agreements. In fact, probably the most important assets that navies have are these land-based bases of operation.

When I was working with the MoD, an officer said to me that the reason the why the US Armed Forces are the best in the world is not because they have the best weapons (they do), or they spend the most (they do), or because they have the biggest armed forces (China does), or because they have the best fighters (mmm…arguable). But they have by far the best logistics of any armed force. It is a truly herculean effort to sustain a highly sophisticated fighting force overseas for months or years on end, all while protecting the fragile logistical vessels that keep the combat ships armed and fuelled.

The inescapable reality of maritime chokepoints necessitates a fundamental shift in how nations approach global security and economic resilience. States can no longer rely solely on the reactive deployment of naval power to solve crises once they have erupted.

The lessons of recent years, whether it be drones in the Persian Gulf and Black Sea or rockets in the Red Sea, point towards tactics of multi-modality that build resilience into global transport systems. This means developing robust overland rail freight networks, expanding pipeline infrastructure, and investing in secondary, alternative maritime routes to reduce the reliance on passage through straits. It requires the onshoring or nearshoring of critical manufacturing to shorten supply chains and reduce the volume of essential goods that must pass through highly contested waters.

The global economy is a brilliant, highly optimised, but terrifyingly fragile construct. It is perfectly reliant on the uninterrupted, clockwork movement of goods, energy, and food across the world’s oceans. Maritime straits are the vulnerable points of this entire system. They are transport corridors fraught with physical limitations, environmental hazards, and acute geopolitical perils.

For military planners and national security strategists, these narrow strips of water force modern navies to adapt to asymmetrical threats, to invest heavily in cutting-edge defensive technologies, and to maintain a constant, exhausting global posture to deter aggression. If you block or take the strait you can apply a lethal chokehold to the global economy. Safeguarding these vulnerable transport systems is the paramount prerequisite for global stability.

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👩‍🎓 Latest Research

The clever clogs at our universities, government departments, and other clever people have published the following excellent research. Where you are unable to access the research, email the author – they may give you a copy of the research paper for free.

Incorporating user travel behavior into bike‑sharing destination prediction: a data‑informed macro‑micro integration approach

TL:DR - Couples city‑level flows with individual behavior to improve station‑level demand prediction. Which is useful for rebalancing and siting decisions.

Going car‑free: an interventional study in Australia and Saudi Arabia

TL:DR - A rare experimental and behavior‑change study testing what actually helps people reduce car use in contrasting urban and cultural contexts.

Performance analysis of multi‑objective demand‑responsive transport as a replacement for local bus lines

TL:DR - Evaluates if DRT can sustainably substitute lightly used fixed routes, balancing service coverage, wait times and cost.

CarPLAN: Context‑Adaptive and Robust Planning with Dynamic Scene Awareness for Autonomous Driving

TL:DR - Advances imitation‑learning motion planning with a mixture‑of‑experts decoder and displacement‑aware encoding, tested on nuPlan/Waymax.

Evidential deep learning for quantifying uncertainty in lithium‑ion battery remaining useful life (RUL) estimation

TL:DR - Brings uncertainty‑aware diagnostics to EV batteries—valuable for public fleets (buses, vans) when scheduling duty cycles, depot charging and TCO.

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😀 Positive News

Here are some articles showing that, despite the state of the world, good stuff is still happening in sustainable transport. So get your fix of positivity here.

National pipeline for 23,000+ zero‑emission buses published

The Department for Transport released a 10‑year zero‑emission bus order pipeline giving manufacturers and authorities visibility of likely demand through 2035—an encouraging market signal for UK production and decarbonisation. Trade press welcomed the outlook while noting the need for more granularity.

Greater Manchester orders 55 more electric buses for the Bee Network

Mayor Andy Burnham confirmed a new order of 55 Wrightbus e‑buses—part of a £66m investment—pushing the region towards a fully electric bus fleet by the end of the decade and supporting UK manufacturing jobs.

TfL’s West London Orbital moves forward—electrification planned on key sections

Design funding and consultation were confirmed for the West London Orbital Overground route; at least the northern section will be electrified, with battery operation considered elsewhere—another step toward cleaner urban rail capacity.

30 brand‑new electric buses arrive for Salisbury

Salisbury Reds, Wiltshire Council and DfT’s ZEBRA 2 funding have delivered 18 double‑deck and 12 single‑deck UK‑built e‑buses, promising quieter streets, better air quality and improved passenger experience across the city (even the Stonehenge Tour goes electric).

Arriva invests £340m with the first new low and zero‑emission buses rolling out in West Yorkshire

Arriva launched a nationwide fleet and depot upgrade programme; the first 50 new buses are entering service in West Yorkshire, with depot electrification projects to follow. Over half of the 809 new vehicles ordered will be fully electric.

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💻 Hard Work

Not too much to report on this week. At least not anything newsworthy. Unless you count endless hours of Teams meetings as newsworthy.

So while I am here, a reminder of two events I am helping to organise. For any members of the Transport Planning Society, they are running their Annual Quiz across the British Isles on Thursday 26th March at 6pm. Current confirmed cities are Birmingham, Cardiff, Cambridge, Dublin, Edinburgh, Exeter, Leeds, Liverpool, London, Manchester, and Winchester. You need to book in advance. You can find the contact details on the TPS LinkedIn page.

Also, Mobility Camp is back! On Wednesday 30th September we are heading to Cutler’s Hall in Sheffield for another amazing day, focussing on Enabling Agents of Change. Or as I like to think of it: let’s just get it done. You can get your tickets now by pressing the below button.

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🎶 Musical Finale

This week was a week listening to the classics. One of them was Black Hole Sun by Soundgarden. Yes, the lyrics are a bit…odd. But it still stands up as a great tune 32 years after it was released.