This week, London debuted its ultra-low-emission zone, meaning vehicles that do not meet low-emission standards will now have to pay an extra fee to access its city center.

Although the city introduced congestion pricing over a decade ago, charging all vehicles a daily fee to enter its central business district, ULEZ rules will add an additional fee of £12.50 per day (about $16) for people driving what are deemed polluting vehicles, including most cars made before 2006. That means people driving polluting vehicles into London will have to pay both the ULEZ charge and the regular congestion charge, up to £24 per day (about $31).

The new policy is intended to not only reduce traffic congestion, but also dramatically reduce emissions and pollutants. According to estimates supplied by Mayor Sadiq Khan’s office, the policy could decrease emissions by almost half.

“Thousands of motorists have already started to change their behavior as they prepare for ULEZ by driving less polluting vehicles into the area, and using cleaner transport alternatives including walking or cycling, and public transport,” said Khan.

Road pricing isn’t the only way to encourage low-emission transportation modes. In London, the city is using the funds to deploy transformations that incentivize low-carbon travel, including pedestrianizing its historic center and spending $1 billion on bike infrastructure.

As New York City becomes the first U.S. city to implement congestion pricing, it’s a good time to look at how two smaller American cities are trying to encourage their own shifts from fossil fuel-powered vehicles to cleaner transportation methods.

In Sacramento, which is in the midst of an electric vehicle revolution, the city is increasing access to low-carbon transportation with multiple EV car share programs, electric on-demand buses, and a fleet of dockless electric bikes. The idea is to provide residents with ubiquitous options that don’t require using gas-powered vehicles.

And it seems to be working—more people are riding Jump e-bikes than using Uber ride-hailing services in the city’s downtown.

In addition, Sacramento is offering incentives for people who use low-carbon options by partnering with the transportation app Miles. Like other transit apps, Miles has gamified using non-car transportation, but it also adds a rewards structure. So when users opt for lower-emission modes like walking, biking and riding transit, they are awarded points that they can apply towards food and drinks at local businesses. All the data goes to the city, which planners can use to make decisions about how to help people move around.

Of course, even with the possibility of winning a Starbucks gift card, most people won’t ride bikes or scooters if they don’t feel safe. Over in Cambridge, Massachusetts, the city approved a new plan this week to make protected bike lanes standard for any street that’s being upgraded. The city’s Cycling Safety Ordinance is the first municipal law in the country that will mandate construction of permanent bike infrastructure. Supporters of the law say it will end up creating a safe, separated 20-mile network connecting the city’s major destinations.

What makes Cambridge’s ordinance so powerful is that it removes the ambiguity around where bike lanes should go, which often ends up slowing or eliminating their implementation. By making bike lanes part of capital projects that have already been deemed necessary to help people get places they are trying to go, the new lanes will end up making bike trips faster and more direct, instead of funneling riders onto side streets. In turn, riders will be rewarded with efficient new routes that help them avoid vehicular traffic while utilizing low-emission modes.

Over 400 U.S. cities have pledged to work together to reduce emissions, yet few are taking the dramatic steps needed to curb transportation emissions, which continue to rise. By rewarding low-emission behavior and prioritizing decarbonized travel, city leaders can make it easier for residents to make the switches necessary to help achieve their climate goals.