Why Cities Need Tailored Plans For Sustainable Mobility
Summary of results
Urban mobility can be the driver for global cities to reach their Paris Agreement goals by 2030. There is still time and an array of solutions at their disposal.
Each city has a unique set of attributes such as population, density, and modal shares. Choosing the right, individualized pathway requires a comprehensive understanding of each city’s features. While every city is different, our research buckets them into three categories: multi-transport cities with a balanced set of mobility offerings, from mass transit to shared and micromobility; car-dependent cities in which cars are overwhelmingly the most used mode of transit; and emerging cities in developing economies with weak mass transit networks and low levels of government investment and infrastructure. These categories not only reflect the variance in mobility networks but also broadly organize the most feasible solutions for each type of city.
The results of our research, summarized below, highlight the need and reasoning for different approaches to sustainability.
To align with cities’ ambition and priorities, solutions are folded into four urban mobility scenarios, offering multiple options to reach the 1.5° Celsius global warming limit:
- A default scenario minimizes any behavior change, yet seeks to decrease emissions.
- An electrification scenario accelerates the shift from gasoline vehicles to electric vehicles.
- A multimodal scenario encourages the use of shared and public mobility.
- An active mobility scenario promotes walking and cycling.
Current modal splits for each archetype reflect the uniqueness of their challenges and how to resolve them. Car-dependent cities overwhelmingly rely on cars, which make up 85% of their modal split, while multi-transport and emerging cities have a diverse modal mix. Public transit and cars make up more than three-fourths of the modal split in multi-transport cities, with walking accounting for most of the remainder. Emerging cities are typically reliant on public transit (including paratransit), with the remaining modal share largely split between cars and motorbikes and mopeds.
Identifying those modal shares helps target where emissions reductions are most needed. For example, since cars make up 85% of the modal split in car-dependent cities, much of the 49% emissions reduction needed must come from electrifying cars or reducing car demand. Car emissions are likewise a priority for multi-transport cities but are a goal in parallel with public transit emissions. Emerging cities have to reduce emissions by 30%, the lowest rate among the three archetypes, due to less comparably mobility demand — although public transit, car, and moped emissions should be reduced. Electrified mobility is by far the most recommended method in our research for cities to decarbonize, even among cities that already boast a holistic network and have strong sustainability plans. But for many of even the best-situated cities in our research, an energy grid reliant on coal or fossil fuels negates the benefits of an electrified fleet.
Electrification and clean energy grids are common threads that run through each of the three city archetypes. But the degree to which electrification is necessary depends on the city’s unique makeup.
Even cities with strong mobility networks need to slash emissions at the highest rates.
Average multi-transport cities’ attributes and trajectory
Multi-transport cities are those with holistic mobility networks, boasting the most balanced modal share splits. And yet, while some cities in this category, like Shanghai, Hong Kong, and Singapore have strong public transit networks, they have a greater challenge in achieving climate targets due to their carbon-intensive energy grids that rely on fossil fuels.
But these cities generally enjoy a greater flexibility thanks to the range of solutions they can leverage to bring down emissions. San Francisco is the outlier among all cities in our research, only requiring a 29% emission reduction to reach the 1.5°C goal or 11% on top of its existing city plans. The Bay Area city aims for electric vehicles to compose at least a quarter of registered private vehicles and 80% of trips to be low carbon by 2030 and has a $40 million plan for more equitable, transit-centric housing development to boost public transit use.
New York, Singapore, and Hong Kong, cities with robust mass transit systems, likewise boast a higher degree of flexibility in choosing which scenario works best. The electrification and multimodal scenarios are best for New York, which already has a power grid that is transitioning to more sustainable sourcing. New York began a $35 million project to expand subway lines and pledged to build more micromobility infrastructure in 2023 and has plans for increased electric vehicle uptake.
Hong Kong’s public transit system, which topped the Oliver Wyman Forum’s Public Transit ranking, has an incredible 71% modal share. With that ridership already so high for Hong Kong’s public transit system, the city should instead turn to a multimodal scenario to increase shared mobility modes, especially car-sharing and bike-sharing. But Hong Kong should combine that approach with electrifying cars and buses while decarbonizing its energy grid. Singapore, likewise with dense public transit infrastructure, should opt for a similar solutions as Hong Kong.
Electrification and decarbonizing energy grids are the clear advice for the other cities in this category, like Shanghai and Berlin. Paris likewise should electrify, particularly because of its low-carbon grid.
Overview of multi-transport cities’ attributes and trajectory
Cities dependent on cars must take advantage of their potential
For cities like Dubai, Los Angeles, and Mexico City, employing scenarios other than heavy electrification are possible, but unrealistic to achieve. Particularly in Dubai, hot climates may make active mobility an unappealing option for long distance travel, while the default scenario would require nearly halving mobility demand in each city. And public transit isn’t comprehensive enough to serve all travelers just yet – although each of these cities have committed to bolstering mass transit offerings.
Average car-dependent cities’ attributes and trajectory
These cities must comprehensively electrify their mobility fleets, and they should use their legacy of heavy car use to their advantage. These cities have the existing infrastructure to accommodate high car usage, making the electrification scenario the most feasible.
Los Angeles, where cars control a whopping 93% of modal share, must cut emissions by 58% to hit their Paris Agreement targets. California’s ban on the sale of new gasoline-powered vehicles beginning in 2035 will help accelerate the pivot to more EVs on the road. Additional local efforts are underway: The Los Angeles City Council approved a plan in 2022 to electrify more than 10,000 city vehicles, and LA Metro aims for a 100% electrified bus fleet by 2030.
Dubai and Mexico City must reduce emissions by 45%, but both have high-carbon power grids that will likely continue to emit high emissions by 2030 (particularly Dubai’s grid, which is highly dependent on fossil fuels). That will reduce the impact of both cities’ efforts to encourage more EVs if the electricity isn’t sustainably sourced.
Overview of multi-transport cities’ attributes and trajectory
Cities in emerging markets need large investments in urban mobility
Emerging cities, like Lagos, are centered in developing countries with low government investment in infrastructure, resulting in weak public transport networks and shared mobility support. And yet, demographic and urbanization booms are in progress that, in part, will contribute to a 50% rise in emissions.
Overview of emerging cities’ attributes and trajectory
Commuters heavily rely on public and para- transit given there are few alternatives, including personal cars. As a result, the electrification scenario fits Lagos best, particularly given its urbanization boom.
High carbon emissions are typical of developing economies, as population growth paired with new opportunities for work and travel rapidly accelerate mobility demand. Lagos faces those same risks, but new technologies give it a way to leap beyond those growing pains, quickly lower its carbon footprint, and modernize its mobility network.
Lagos still lacks legacy electric infrastructure for both its mobility fleets and its energy grid. Efforts are underway: Lagos’s Metropolitan Area Transport Authority has partnered with energy company Oando Clean Energy to offer electrified buses as an alternative to conventional BRTs and Danfo buses. But much more investment and international support is needed.