To tackle climate change, scientists say that we need to hit net zero emissions by 2050. To make those policies more clear, Energy Innovation has debuted a new analysis that calculates exactly which policy changes are needed in the U.S. to reach that goal, using a tool the group developed called the Energy Policy Simulator.

As electric cars continue to get cheaper, they’ll naturally replace more and more fossil-powered cars—but not quickly enough to get to net zero emissions by midcentury without more aggressive policy shifts. Other parts of the transportation industry, including ships and aviation, will be harder to transform. These are the key policies that will need to be implemented:

Electric vehicle sales requirement: Since vehicles can last for decades, getting to net zero by 2050 means ending sales of new fossil-powered cars very quickly. By 2030, 100% of new cars, motorcycles, buses, and trains will need to be all-electric. Half of new medium- and heavy-duty trucks will have to be all-electric. Seven other countries also have bans on new fossil vehicles sales set to take effect in 2030. This policy will cover 73% of the needed emissions reductions.

Transportation demand management: Changes in policy can help encourage people in cities to drive less, including encouraging new building near transit hubs and improving public transportation. Because vehicles are shifting to clean energy, though, these policies are only responsible for 13% of emissions cuts in the sector.

Hydrogen vehicle sales requirement for trucks: Trucks that travel long distances are more challenging to run on electric power, so this policy says that 50% will have to run on hydrogen by 2040 instead.

New efficiency standards for airplanes (a 25% improvement by 2040), ships (a 20% improvement by 2040), and to a lesser extent, other vehicles, which will already be transitioning to clean energy.

Read the full article about how the U.S. gets to zero carbon emissions by 2050 by Adele Peters at Fast Company.