Los Angelinos hurling e-scooters into the ocean. Residents of San Francisco and Chandler, Arizona sabotaging driverless cars. Barcelonians squirting cruise ship passengers with water pistols. Borrowing from the Latin term persona non grata for labeling an unwelcome person, modus non grata describes when modes of transport are similarly ostracized and made into proxies in conflicts about the futures of cities.

The origins of these aggressions are straightforward when we consider that the transportation we use reflects our values. This is true for us as individuals and as communities, and this is especially true when a mode of transport becomes a symbol of adjacent socioeconomic and ecological conflicts. Los Angelinos hurled e-scooters in the ocean because those scooters are emblems of gentrification. Residents of San Francisco and Chandler sabotaged driverless cars because those vehicles are exemplars of an erosion in public trust. Barcelonians harassed cruise ship passengers because cruise ships are representations of over-tourism.

The conflicts are about something else, but transportation is the way we fight about them. So far, this era of modus non grata has emerged within individual cities. But there are signs that it will go global with transformative effects.

The big reason modus non grata is poised for global expansion is the rising political power of cities. In countries around the world that are politically polarized, it’s cities—not central or regional governments—that are the most cogent unit of political power. Consider these examples: Debates about gun control measures have persisted in the United States for decades, but it’s a city—San Jose, California—that passed the first law in the nation requiring gun owners to carry liability insurance. While obesity and diabetes are national concerns, it’s cities lke Seattle and Philadelphia that have enacted taxes on sugar-sweetened beverages as a policy focused on improving citizen health.

Why does this matter to transportation? City-led policy actions on public safety and health aren’t far removed from similar actions that would affect transportation—and it’s already happening. Today, many cities around the world are barring large cruise ships from their ports due to over-tourism and environmental concerns. Tomorrow, similar policy actions could limit port access to only ships using fuel cells and renewable hydrogen. Airports governed by city-influenced port commissions could impose additional landing fees on aircraft using traditional jet fuel while economically favoring those using sustainable fuels. Cities could dictate aspects of autonomous vehicles’ programming to produce behaviors preferred by the municipality, such as favoring trips to and from retail districts or even enforcing questionable teen curfew laws. Through do-this-or-leave policy actions, the local levers of modus non grata could grow outward from cities around the world to reshape the global transport ecosystem.

A utopian version of this future, the policy actions of the world’s cities align around equitable and sustainable principles to advance efficient, accessible, and responsible human mobility.

While cities almost always tend to be seats of progressive politics, smaller cities that lean more toward conservative ideologies could theoretically implement their own retaliatory policies, including banning electric vehicles, prohibiting the use of sustainable fuels at their municipal airports, and so forth. A dystopian version of this future produces a fractured transportation landscape in which whole fleets of commercial aircraft, cruise and cargo ships, autonomous vehicles, and other modalities are welcome in some cities and unwelcome in others.

But in a utopian version of this future, the policy actions of the world’s cities align around equitable and sustainable principles to advance efficient, accessible, and responsible human mobility. Fortunately, it’s the utopian version that appears more likely based on the political postures of cities, how those cities are networking, and the fact that transportation providers simply cannot afford the dystopian version.

So, what steps can transportation designers, manufacturers, and operators take today to avoid a modus non grata future? These are the big three:

/01

Minimize have/have-not propositions.

Here’s a fast-track to modus non grata: creating transportation experiences that illuminate economic inequities. In New York City, Uber’s earnings per ride have increased 218% over the last five years while drivers’ share of those earnings have decreased more than 10%. The optics of these figures suggest ridesharing companies are maximizing profitability for investors, and widening the gap between those who can afford these app-based services and those who rely on public transit—all while squeezing labor. This is creating conflicts with cities keen on ensuring living wages for drivers.

These are cautionary signals for future eVTOL and autonomous vehicle fleet operators, both of which have the potential to serve marginalized passengers. Delivering on that potential will require cities to operate their own fleets or tightly regulate how independent operators structure fares if we’re going to make those future services accessible to everyday citizens. Otherwise, those independent operators risk getting nixed by cities focused on solving systemic inequities.

/02

Design more value for cities.

Modes of transport like commercial aircraft and cruise ships aren’t designed for cities—they’re designed to move between cities. How they perform when they’re in cities isn’t part of their reason for being, so designing new ways of delivering value to cities will be essential if they want to maintain their welcome.

In aviation, this means operating cleaner and quieter aircraft powered by sustainable fuels. Dirigibles, as a new kind of aircraft operating in a warming world, might even serve as urban shade providers. Cruise ships, which have already doubled as hotels during major events, will similarly need to innovate new ways of adding value to locals. Even modes of transport designed for in-city deployments, such as autonomous vehicles, will need to add more value to cities while idle, such as illuminating unlit streets, serving as mobile Internet hotspots to underserved communities, and bringing back doctor’s house calls to homebound patients.

/03

Integrate through intermodal connections.

New modes of urban transport often create an otherness about them, either because their rollout strategies involve arriving unannounced—which was the case with e-scooters—or their development stages require testing that only involves a subset of the public—which is the case with autonomous vehicles. This unintentionally positions them as interlopers within existing transportation systems. There’s a way around this problem: creating intermodal connections with those existing transportation systems. Integrating with existing systems turns new operators into collaborators, which is a far more welcome proposition than competitive threats and challenges to shared public spaces and the established norms of existing modalities.

Here, there are enormous opportunities for win-win intermodal collaborations. Shared bicycles and e-scooters should integrate with public transit payment platforms. New eVTOL fleets should connect with moving trains to reduce unnecessary station stops. Autonomous vehicle fleets should use smart contracts to take over bus routes late at night and during other off-peak hours when it’d be safer, more efficient, and more cost-effective for the city.

Originally published in Fast Company magazine