The last leg of the distribution chain is one of the most severe polluters in transportation today. Unmanned aerial vehicles might reduce emissions, by providing an alternative route of delivery in urban settings as well as a short-cut to infrastructure for developing regions.

Transportation is a sector heavily reliant on fossil fuels, making its carbon dioxide emissions second only to those from energy production. Still, many transports, although long distance, are energy efficient due to large volumes. A commodity’s final car journey to its destination might actually use 200 times the amount of oil (per kg of load) as the entire crossing of the ocean. Much of the environmental issues with transportation are hence accumulated from numerous short trips, forming a hard-to-manage emission source distributed in time and space.

Transport of goods have been made more efficient by smarter route planning and management, aided by GPS and computerization. But recent technology might also allow for more drastic changes to the world of transportation.

Drones find new functions

Unmanned aerial vehicles, or drones, is a concept encompassing large and expensive fixed-wing aircraft, small, cheap, battery-driven quadcopters, and everything in between. They might be remote-controlled, or autonomously navigating, only monitored by a crew on the ground.

During the last decade, UAV:s have found increasing military use. But rapid development in battery-, sensor- and control technology are beginning to foster visions of widespread civilian application as well – in ten years, drones might have ten percent of the air freight market, according to some estimates.

Quadcopters, four-rotored helicopters, are an age-old design only recently made practically feasible by the evolution of electronics. To keep them balanced, a control unit continously takes readings from various sensors and adjust the rotors accordingly. With simple and light-weight design, good maneuverability and the ability to hover, they are excellent candidates for both transport and other tasks.

Urban first aid-drones is one idea. When a call for assistance is registered, a drone carrying a defibrillator could be dispatched immediately, reaching the patient before an ambulance could get there; for heart patients, a difference of even a few minutes would increase the chance of survival substantially.

If drones are able to communicate and synchronize their actions, even more possibilities open. Swarms of drones could be useful for making measurements or observations, of environmental or other factors, covering large areas with small measures.

Solving the last mile problem

The most difficult challenge in transportation is the so-called last mile problem. Up until a certain limit, items can be collectively handled and transported in bulk, and economies of scale come into play. Route optimizations can push that limit further. Eventually, there still will be single packages needed to be transported from repositories to individual destinations. Fetching them by car means moving tonnes of steel back and forth, even if only a fraction of the load capacity is needed; the car also has to follow the road grid, and wastes even more energy in braking and accelerating as dictated by traffic.

One blatant example is taking the car to grocery shop – however convenient, speaking strictly in terms of energy efficiency it is far from optimal. When it comes to tasks like this, light-weight but powerful drones could supply an otherwise seemingly unachievable weight-to-load-efficiency. And if they can be charged from renewable sources of energy, all the better. Efficiency gains would also spread to other modes of transport, as drone traffic would relieve roads from some of the congestion.

New regulations, modified networks

Amazon.com, the worlds largest online retailer, announced plans in 2013 to put drones in widespread service for delivery of their products. Prototypes capable of carrying two kg of load in 80 km/h are being tested. Meanwhile, DHL became the first operator of a regular drone service, carrying parcels by quadcopter between the German mainland and the car-free island of Juist, a couple of kilometers off the North Sea coast.

The DHL choice of route makes sense, as it avoids many challenges which lie ahead in adopting drone technology. In denser traffic and urban settings, drones must be able to detect and avoid both one another and other obstacles. Security and integrity will be crucial, and with the lack of a pilot, it must be considered who should be held accountable should an accident occur. Existing rules and regulations are hardly adequate, and new and updated ones will be needed. The EU is currently assessing the issue, looking to develop a framework of standards.

To reap all the potential benefits, modifications to transport networks will probably be required, and repositories relocated to match the working range of the drones. Or perhaps trucks could be housing on-board swarms of drones, making deliveries to nearby destinations before returning to their mobile beehive?

All drones won’t be airborne

A break-through of unmanned delivery would likely affect sea and road traffic as well. Rolls Royce is a pioneer in drone ships, currently doing research and development in Norway. They believe tankers and freight ships soon could be controlled entirely from ashore, without compromising safety, and suggest test traffic will be underway in the Baltic Sea within ten years. Without a crew on board, energy efficiency would increase as the space used for their compartments could carry load instead.

Automated trucks and cars are also subject of intensive research. For instance, Volvo Car Corporation has participated in a successful project called SARTRE, where environmental road trains were tested on unmodified highways. A lead vehicle with a driver would be followed by automatic vehicles in close order formation, thereby reducing drag, fuel consumtion and emissions.

A shortcut to development

Delivery by drone could help the environment in other ways as well. Developing countries tend to use cheap but polluting sources of energy and outmoded technology. Increased wealth creates the margins needed to invest in greener energy and better technology – and new modes of transport can play a big part in the fight against poverty and underdevelopment.

One billion people in the world lack a reliable access to roads. In analogy with how many countries in poorer parts of the world have been able to quickly introduce mobile telephony without ever having installed landlines, a drone-based network of transportation could offer these people a cheaper and faster short-cut to modern infrastructure.

Simple quadcopters could be important vehicles in that context as well, but there are also innovations in heavy transport to be considered.

Cargo zeppelins

The British company Hybrid Air Vehicles is developing a new generation of cargo zeppelins, combining benefits from carriers, airships and drones in the same hull. They are fairly slow, but can carry 50 tonnes – reminiscent of the evolution of shipping, where fuel efficiency considerations have sparked a trend towards larger loads and lower speed, dubbed ”slow steaming” by the industry.

While airships of old needed a lot of crew, the 91 m long Airlander makes do with only two crewmen and very limited resources on the ground. The lift comes not only from the helium inside, but is also generated by the shape of the hull – spindle-shaped segments, side by side. This makes the Airlander faster and more maneuverable than airships, and 70 percent more fuel efficient than a cargo aircraft.

What the role of unmanned vehicles will be in the transportation networks of tomorrow is yet to be seen. But they are providing novel opportunities for transport on the seas and oceans, in the air and in the streets, and in developed regions as well as where infrastructure is lacking. And importantly, they seem to be able to address domains where emission reduction has been lagging and would otherwise be difficult.

The article was published in February 2015