Los Angeles Mayor Eric Garcetti and Stockholm Mayor Anna König Jerlmyr both noted on Wednesday during Fortune’s Global Forum that they hoped their cities could experiment with new technologies to cut their carbon emissions fast.

Despite L.A. being known for its heavy dependence on cars, Garcetti is hoping the city can become the “transportation tech capital of America, if not the world.” He said that cities should be a “hotbed of experimentation” for any new technology that could cut carbon emissions.

König Jerlmyr agreed saying, “As mayors, we often want our cities to be test beds. It is much more difficult on a national level, but we can provide citizen engagement.”

Both cities are looking to reach zero emissions before the Paris Agreement target of 2050.

L.A. hopes to make its electricity grid—the largest municipal grid in the U.S.—completely carbon-free by 2035, which would be achieved by cutting carbon emitted by public transportation and buildings. It is also looking to cut waste and wastewater to zero, according to the mayor.

Meanwhile, Stockholm is looking to be fossil-fuel–free and climate positive by 2040—by pushing new technologies like carbon capture and storage and completely electrifying its grid.

But in the race to build the greenest transportation system, Stockholm might have a starting advantage. Garcetti notes that people forget that fixing this problem is not just building out billions of dollars of infrastructure or forcing people to take public transportation. “It is building more self-contained neighborhoods, good urban planning. Stockholm knows this. It’s a beautiful city where you can walk to where you work, eat, play, live,” says Garcetti.

But picturing L.A. without its flashy convertibles powered by internal combustion engines might be beyond the imagination of many.

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