From the EPA, on US emissions:

Transportation (28% of 2021 greenhouse gas emissions) – The transportation sector generates the largest share of greenhouse gas emissions. Greenhouse gas emissions from transportation primarily come from burning fossil fuel for our cars, trucks, ships, trains, and planes. Over 94% of the fuel used for transportation is petroleum based, which includes primarily gasoline and diesel.

The largest sources of transportation greenhouse gas emissions in 2021 were light-duty trucks, which include sport utility vehicles, pickup trucks, and minivans (37%); medium- and heavy-duty trucks (23%); passenger cars (21%); commercial aircraft (7%); other aircraft (2%); pipelines (4%); ships and boats (3%); and rail (2%).

Driving accounts for a larger percentage of emissions than you'd think - something like 14% of emissions are gasoline alone.

Electric cars have about half the lifecycle emissions of gas cars, so that's equivalent to a ~7% reduction in emissions - more if the grid goes solar.

That said, replacing suburban sprawl with traditional denser streetcar suburbs like you see in the Netherlands would be a much bigger reduction in emissions.