Zero-emission Zones Are Helping Some Cities Fight Pollution

With growing urban populations and increases in cars, trucks and buses, cities are poised to experience more harmful pollution threatening people's health and livelihoods.

But some cities around the world are turning to an emerging solution called zero-emission zones (ZEZs).

These are designated small areas of about 1.5 square miles to 11 square miles inside large cities in Europe, Asia and North America where only zero-emission vehicles (such as electric cars and trucks), pedestrians and bikes are granted unrestricted access, with gas and diesel vehicles either prohibited or forced to pay an access fee.

What Are the Pros and Cons of Zero-emission Zones?

The policy, which requires limited public funds, considerably reduces emissions and can bring additional environmental and economic benefits. For example, research shows that ZEZs can reduce most tailpipe nitrogen dioxide emissions from trucks - a major source of air pollution. Further, carefully-conceived ZEZs are expected to reduce the number of cars on the road making cities less congested and helping spur the market for more zero-emission vehicles.

Although city leaders often like the idea of ZEZs, they are also daunted by the possible negative socioeconomic impacts of the policy. For example, the high costs of new zero-emission vehicles or access to transportation may impact low-income residents and vulnerable groups living in the zones, who need to get to work or school. Or small freight carriers may not be able to reach their customers, disrupting the supply of food and other goods.

Overcoming Barriers: Lessons from Zero-emission Zones Leaders

Still, even though ZEZs are still a nascent approach with some knots to untangle, several cities are beginning to implement them. A WRI report, "Feasibility of Zero-Emission Freight Zones: Scenario Analysis and Risk Assessment," shows only about a dozen cities around the world have officially implemented or announced formal proposals to pilot ZEZs. Currently, these cities include Rotterdam and Amsterdam in the Netherlands, London and Oxford in England, Brussels in Belgium, Santa Monica and Los Angeles in the United States, Oslo in Norway and the cities of Shenzhen, Foshan, Dongguan and Hangzhou in China.

These early adopters have already found effective ways to implement ZEZs, offering lessons for other cities:

1) Start By Targeting Trucks

When first implementing a program, it's more common to prioritize trucks over private cars for a couple of reasons. First, in recent years, banning gas-powered private cars from entering ZEZs (often in city centers) could have profound accessibility impacts for local residents and stimulate widespread public objection. Further, compared with the soaring market shares of electric passenger cars (22% in the EU, 35% in China and 9% in the U.S. by 2023), the adoption of zero-emission trucks has been much slower. Implementing more policy instruments like ZEZs can help stimulate the growth of zero-emission trucks.

To reduce air pollution and to bring the transport emissions close to zero by 2030, Amsterdam initially proposed to introduce a ZEZ for all vehicles - including private cars - within the city's built-up area (which is almost the entire city) in 2030. However, due to concerns about public acceptance, the city postponed private car restrictions to after 2030, to provide ample time to foster public support. Instead, the city plans to pursue a ZEZ for trucks inside of the A10, a ring road circling Amsterdam, beginning in 2025.

Within the truck segment, light-duty trucks and vans will be targeted first in Amsterdam, because heavy-duty trucks - particularly long-haul trucks - have limited zero-emission models and are too expensive to purchase.

A PostNL truck parked along the side of a road in Amsterdam. The Netherlands mail service uses electric trucks to make its deliveries in city centers. Photo by Bjoern Wylezich.

Amsterdam is not an isolated case. All the global cities WRI studied restricted or plan to restrict gas- or diesel-powered trucks in the initial phase of implementing a ZEZ policy. Only London and Oxford have also banned private cars, which will be planned pilots on a few streets that are less than 1 kilometer (0.62 miles) long.

Oslo plans to target both gas or diesel-powered light-duty trucks and heavy-duty trucks in the first phase of its ZEZ implementation. Chinese cities, such as Dongguan and Hangzhou, are also banning diesel heavy-duty trucks from entering the ZEZs, aiming to eliminate heavy-duty trucks in the city center. Arguably, this measure could lead to increased freight movements and worsen traffic congestion since heavy-duty vehicles could be replaced by many smaller vehicles.

2) Small Zones Avoid Bigger Challenges

Cities need to make sure the design of ZEZs doesn't disrupt the supply of goods and interfere with a city's economic and social activities. Opting for small zones, like Shenzhen did, is one strategy to avoid these challenges.

As part of the 2018 "Shenzhen Blue" Sustainable Initiative, the city government created to quickly curb air pollution, 10 ZEZs were established. But to manage potential public objection, the city started by designating small zones in high visibility areas of the city.

Under the rationale, the 10 zones totaling 22 square kilometers (8.5 square miles), or 1.1% of Shenzhen, were established in the center of each urban district where there were high levels of air pollution, traffic congestion and parking shortages. The individual zones span from 0.37 to 5.4 square kilometers (0.14 to 2.1 square miles).

Some ZEZs are also located around city government offices or public schools to take advantage of public procurement of zero-emission trucks and avoid impacting local residents.

In 2023, Shenzhen introduced six additional ZEZs near universities and public parks to further accelerate the adoption of zero-emission trucks, increasing the total ZEZ area to 26 square kilometers (10 square miles).

Similar to Shenzhen, most of the global cities WRI analyzed have all started or planned to implement ZEZs in small areas that measure 4 to 31 square kilometers (1.5 to 12 square miles). Some cities are also exploring other small locations outside of city centers. For example, the Chinese central government is considering establishing ZEZs (or ultra-low emission zones) at industrial parks, seaports, railway yards and airports.

3) Create Support Measures for Small Businesses

Small trucking companies serving areas and neighborhoods within ZEZs are particularly vulnerable to the economic impact from new ZEZ policies. Therefore, supportive measures should be designed to protect this segment of traffic that would need to reach residents and businesses located in these zones.

Staff from a zero-emissions delivery program use an electric cargo trike for distribution. Zero-emissions delivery will be a critical practice as ZEZs continue to grow. Photo by Simon Turner/Alamy Stock Photo

In Rotterdam, during the transition to electric vehicles, small trucking companies, which transport goods in and out of the city, warned that the high transitional costs from purchasing new vehicles would diminish their profits. But supportive government measures were created to help. The city of Rotterdam expanded subsidies created by the Netherlands that encouraged small carriers to purchase electric trucks. The city is also providing advice on costs, information on relevant subsidies and tax exemptions, advice on charging solutions and making free trials of zero-emission vehicles available.

Further, to ensure small companies are prepared for the new policy, Rotterdam is also providing a long phase-in period. The ZEZ policy, which covers 13 square kilometers (5 square miles) and restricts various sizes of trucks from all-day access, was communicated to the public in 2020, about four years before its implementation is set to begin in 2025. In addition, Rotterdam included a 3 to 5 year phase-out period for existing gas- or diesel-powered trucks (Euro V and VI). These trucks won't be banned completely until 2030 so that small companies don't have to retire newly-purchased gas- or diesel-powered trucks and can buy zero-emission vehicles at cheaper prices.

Last but not the least, Rotterdam is expanding the battery-charging network at public parking lots and major destinations (such as distribution centers, offices and depots). It is also addressing issues such as the interoperability of chargers and the charging impact on the grid systems.

4) Combine Zero-emission Zones with Additional Benefits

ZEZs do not necessarily generate additional benefits such as congestion relief or delivery efficiency. For example, zero-emission trucks may not be able to travel as far as gas- or diesel-powered trucks before needing to recharge and the heavy weight of the batteries may mean these zero-emission trucks can carry less goods. This leads to operational inefficiencies and increased traffic congestion. Therefore, cities need to go beyond the single goal of emission reduction when designing ZEZs.

When the city of Rotterdam created its policies, it wanted the ZEZs to have multiple goals: achieve zero emissions, efficient operation and zero congestion through the implementation of the ZEZs. To tackle operational inefficiency and create additional benefits, Rotterdam adopted a series of efficiency improvement measures, including establishing urban consolidation centers outside the ZEZ so that goods from various origins are bundled into fewer vehicles and distributed to ZEZs and adopting efficient delivery practices (such as data-driven route planning) to reduce empty runs.

Successfully Achieving More Zero-emission Zones

Accelerating the transition to more zero-emission vehicles is vital to improving air quality, reducing human health risks and lowering emissions that harm the climate and environment. While the introduction of ZEZs may be daunting, cities like Amsterdam, Shenzhen and Rotterdam show that creating ZEZs is possible. However, it's important that the policies should also avoid negative impacts that could impact small trucking companies and residents, as well as create co-benefits for operational efficiency and congestion alleviation.