From the neo-liberal point of view, cities are becoming multimodal; there should be something for every taste. Investment in public transport, such as metros or light rail, is accompanied by increases in road capacity. New housing development involves apartment buildings, row houses, and single-family homes. Technologies with high carbon emissions and those with low emissions are being added. These market shares of each are not necessarily combined to yield improvements in the environment and total carbon emissions.

This must change. “Sustainable urban development and mobility development is not only about promoting environmentally less damaging niche technologies and products, it is also about actively constraining and shrinking the existence of the unsustainable ‘products’ – novel as well as old ones—that are part of the multi-segmented regimes. At least, the market shares of the environmentally favorable solutions must be increased significantly at the cost of the more polluting and resource-consuming ones.” (Naess & Vogel, p. 9 2012). For transportation, this implies a move away from cars to multimode transport involving better public transport through subways, buses, light rail, and more bicycling and walking.

We cannot expect electric vehicles to resolve the problem of transportation. “Urban car traffic causes a number of social and environmental problems in addition to energy use and emissions, such as traffic accidents, barrier effects, congestion, noise, and the encroachment of transport infrastructure on green areas and existing built environments. These problems will not be solved through the introduction of ‘clean cars’ “ (Naess & Vogel, p. 3 2012). Cities aspiring to sustainable development will have reduced car use in favor of better public transportation, more bicycling, and walking. The buildings will be high-density, limiting single-family houses and other low-density structures.

A compact city is one of the key concepts in sustainable urban development. Clearly, it is difficult and expensive to provide high-class public transport in low-density urban districts. Instead, with short distances to potential destinations, a higher proportion of trips can be made by bike or foot. The remaining shorter motorized trips will produce fewer gas emissions than the longer trips of low-density areas. Locating a high proportion of new buildings close to the city center contributes to reduced energy use and gas emissions from transport. This applies to residential development and office workspaces.

There is a choice of homes in high-rise buildings (often with swimming pools and gyms), smaller apartment buildings, and duplexes, but space for dispersed single-family homes is limited. Local service facilities such as primary schools, kindergartens, and grocery shops should naturally not be centralized in the downtown area but interspersed with residential areas all over the city.

Thus, sustainable urban development will increase the share of low-carbon modalities and actively decrease the share of those with high carbon emissions. Returning to the neoclassic model, we may concentrate our different tastes on the diverse low-carbon solutions. Certain sustainable cities will favor more biking, others more green spaces, others more walking, others light rail, and so on.

Even the difference between single houses and duplexes can significantly change density and sustainability, at least in Palisades Park, New Jersey, two miles from the Washington Bridge in New York City. The Big Apple is home to our largest economy, but its suburbs are almost all zoned for single-family homes. Palisades Park was weird when it passed its first zoning code in the 1930s; they wrote the law reserving the land for single-family houses or duplexes. Initially, the town was constructed as a single-family community, but as the demand for housing in New York increased, more people wanted to live there, and more duplexes were built. Palisades Park was able to grow and make room for more people who wanted to be part of New York's story. The town is vibrant because more people are also living there as customers.

Single-family zoning grew up in the early 20th century, basically as a system for preventing minorities from moving into these emerging suburban communities. You couldn’t build an apartment building there. You couldn't build a duplex. It was basically. Anyone who can afford a single-family home is welcome to come. Well, in practice, what that meant is that these communities remained white and exclusive. And so, by the mid-20th century, what you have is that much of the American landscape around urban areas is reserved exclusively for single-family development. (Applebaum, p 2, 2024).

International research on urban transportation modes shows significantly increased odds of transport-walking within the neighborhood when households were located within 800 m of a train station and within 400 m of a bus stop. “Although causality cannot be conferred by cross-sectional data, these results provide some evidence that a shift from private motor vehicle use to active and public transport use has the potential to be achieved through careful integrated urban and transport planning that prioritizes pedestrians, cyclists, and public transport users. The effectiveness of this approach has been demonstrated in a number of North American cities, including Portland, San Francisco, Minneapolis, Chicago, Washington, New York, Vancouver, and Toronto.” (Boulange et al., p. 164, 2011).

Portland, for example, has a closely connected bike network from three to six blocks from anywhere in the city. There is an extensive grid of bike boulevards with traffic-calming features. The bike culture is lively and includes education, promotion, and annual events like Ciclovia. City regulations require that new or reconstructed streets have bike facilities.

For fun, explore the 15 greenest cities in America.

How is your city for biking? What is the quality of your public transportation? Are your green spaces sufficient and well-located? Is it easy to walk to your favorite places? Is there enough housing for everyone? In other words, how is your city progressing towards a more humane and sustainable development?


1 Naess, P., & Vogel, N. (2012). Sustainable urban development and the multi-level transition perspective.
2 Applebaum, B., (2024), We Have a Housing Crisis. This New Jersey Town Has a Solution, New York Times, May 8.
3 C. Boulange et al. (2017), Examining associations between urban design attributes and transport mode choice for walking, cycling, public transport. and private motor vehicle trips, Journal of Transport & Health 6 (2017) 155–166.