Different rates of urbanization and decarbonization in various regions and countries cause transport corridors to become a subject of global competition across transportation modes, increasing both ecological unsustainability (high energy consumption and related greenhouse gas [GHG] emissions) and system vulnerability.

The ecological (un)sustainability and vulnerability of transport systems are usually analyzed either by the topological properties of the transport networks (articulation nodes, served by the corridors), which are highly dependent on urban density, or by studying the demand and supply side of the transport chains (flows) to assess the impact of the disruptions for the users, society, and governments at regional, national, and international levels.

Dependence on energy use by transportation systems is reminiscent of the Newman and Kenworthy “urban density and transport-related energy consumption” hyperbola, showing an exponential decrease in transport-related energy consumption with an increase in urban density. This can be explained by the fact that high urban density allows for efficient planning of multimodal transportation systems for both passengers and goods, reducing transport-related carbon emissions.

Decarbonization Strategies for Transportation Systems

Urban transportation decarbonization relies heavily on emissions monitoring. Most cities currently focus on Scope 1 (GHG emissions from sources within city limits) and Scope 2 (indirect GHG emissions related to the purchase of electricity, steam, and heating/cooling produced outside the city limits but consumed within the specific boundaries of a city).

Communities seriously working toward efficient decarbonization must also consider Scope 3 (all other GHG emissions generated outside the city limits as a result of activities within the city limits) to transform the entire urban ecosystem.

This is already being done by industries that are considering the impactful implementation of the EU Supply Chain Act. Scope 3 emissions should be considered while developing internal carbon-pricing mechanisms to be ahead of political regulations of CO2 pricing, which is currently €30 per ton (about US $32). Forty-four Organisation for Economic Co-operation and Development (OECD) and G20 countries, which are responsible for about 80% of the energy-related global CO2 emissions, had a carbon-pricing score of 19% at the €60 benchmark (about US $64); that is, 19% of emissions are priced at a level that equals or exceeds the benchmark of €60 per tonne CO2.

In 2018, Switzerland, Luxembourg, and Norway reached a carbon-pricing score of close to 70%, acting as leading countries on the transformation pathway. They achieved this score because fuel taxes for road transport are often entirely invested in the road infrastructure; there is a significant CO2 tax for the use of fossil fuels in private households and commercial enterprise; and electricity supply is significantly decarbonized, leading to low industrial emissions.

At the urban level, Oslo, Stockholm, Tokyo, Copenhagen, Berlin, London, Seattle, Paris, San Fransico, and Amsterdam are considered the most sustainable cities in the world. These cities focus intently on energy efficiency, electric mobility, decarbonization of urban logistics, greening buildings, enhancing urban-farming activities, waste management systems, and designing efficient and smart infrastructures.

Digital technologies help companies and communities improve delivery times and optimize supply chains. For example, a project to digitize China-based Huawei’s supply chain focused on mapping real-world objects like contracts and products to the digital world, automatic recording of real-time business processes and operations like cargo transportation, and managing business rules for complex scenarios using digital solutions (e.g., inventory cost accounting and order-splitting rules).

One of the projects in the 2014 United Arab Emirates Smart City program involves tracking, shipping, and delivering imported and exported goods using blockchain technology. Technologies like big data, Internet of Things, augmented reality, artificial intelligence, robotics and autonomous driving, and digital twins are also being implemented to help achieve decarbonization in logistics systems and are being actively used in Dubai Harbour.

In general, technology helps cities design resilient (physical and digital) infrastructure through:

• Implementing efficient multimodal transport chains, which means moving cargo in a single container from door to door by combining land transport (road or rail) and maritime or river transport (vessel or barge) in one optimal transportation chain, which is cost-efficient and saves CO2. A good example of this is how UPS and DHL created services along China’s Belt and Road Initiative so goods could move multimodally from Asia to Europe.

• Bundling material flows in multifunctional smart hubs, connecting transport nodes, subway lines, click-and-collect points, pickup and drop-off points, stores, retail galleries, commercial areas, conference centers, lounge areas, restaurants, shops, office areas, coworking spaces, fitness clubs, housing, cinemas, and underground parking garages. Examples include the Arnhem Central Transfer as a gateway and transport node among the Netherlands, Germany, and Belgium; the Oculus in New York City; Rotterdam Centraal Station, the Netherlands; West Kowloon Station in Hong Kong, China; Anaheim Regional Transportation Intermodal Center (California, USA); and Transbay Transit Center in San Francisco, California.

• Designing energy-efficient warehouses by applying alternative energy sources and building information modeling. This technology helps designers simulate and analyze buildings in a virtual environment prior to construction.

• Implementing hydrogen energy for line-haul trucking. For example, Toyota Motor Europe used its fuel cell technology to decarbonize the Toyota logistics network, reducing the company’s overall carbon footprint and setting it on a path to full carbon-neutrality by 2040. However, the economic viability of this technology is uncertain. It is estimated that fuel cell long-haul trucks can reach total cost of ownership parity (considering diesel fuel prices, road tolls, and other taxes) by 2030 in Europe if the at-the-pump green hydrogen fuel price is around 4 €/kg. This can be achieved by strongly subsidizing the technology, which is not efficient. Thus, proper carbon-pricing programs should be implemented. Some of the largest shipping companies are introducing new frameworks of efficient internal carbon-pricing programs.

• Leveraging autonomous driving systems, including drones and droid deliveries. For example, Volocopter offers an additional layer of transportation for passenger and heavy cargo that will be highly efficient in megacities.

• Applying ultra-quiet equipment and electric vehicles to reduce delivery noise during off-hours operations. For example, the Eco Truck, launched by Lawsons in the Greater London area, is a 26-tonne flatbed truck powered by a natural gas engine that generates 50% lower noise and 99% fewer particulates than an equivalent diesel engine.

• Improving traffic and transportation management systems through route optimization and vehicle (re)routing. For example, Germany-based SEVAS provides data on priority route networks and restrictions for truck traffic; Tiramizoo offers app-based services to the logistics service providers and municipalities to help them visualize and optimize their last-mile routes; and the Transport for London program used Siemens’s real-time optimizer to reduce traffic delay by 13%, which is expected to generate £1 billion (about US $1.2 billion) in benefits by 2036 by reducing delays for all road users.

• Applying collaborative platforms to be shared among logistics service providers. These platforms help providers share their resources (e.g., free capacities in warehouses or tracks), which strongly supports decarbonization of urban logistics. The overall goal is a transition from individually managed supply chains to open supply networks enabling structural collaboration. Companies like LOGISTEED and Collaborative Urban Logistics & Transport (CULT) offer a variety of functions to be shared, including order reception, transport, delivery, and consolidation of volume and storage.

• Producing selected components in local additive manufacturing (also known as 3D printing) stations. Switching from a central factory to local 3D printing lets manufacturers produce components close to their destination. For example, Thyssenkrupp Marine Systems aims to produce components for its submarines in local fjords. Manufacturers can build their own distributed network of 3D printing stations or outsource the production of some components to a third party. Compared to traditional manufacturing techniques, 3D printing can be relatively flexible, which supports contract manufacturers in bundling the production tasks of multiple partners. In addition to shorter transportation distances, local 3D printing arrangements enable component designs that outperform conventional solutions.

[For more from the authors on this topic, see: “Decarbonization Pathways for Urban Logistics Systems.”]