Car usage has a direct negative link to the environment regardless of electric vehicle transition or technology level or anything like that. More car usage will always hurt the environment in game.
Fuel efficiency standards please environmentalists, but do not directly benefit the environment. They do however, increase car usage. Therefore, implementing fuel efficiency standards has a net output of dropping the environment. Conversely, canceling fuel efficiency standards improves the condition of the environment.
Was this indirect link intentional?
Well i think it was intentional. But yeah electric transition ruins it a bit: If you read the text attached to the policy it reduces the cost of driving by reducing the fuel demand and makes it cheaper to operate a car → car usage goes up. So it makes sence before the electric transition took place. On the Other hand you could also see it that electricity is also a kind of fuel. If this fuel is used more efficient more people will use the car instead of railroad or bus because it is cheaper. So it still makes sence.
Yes, plus cars are themselves very bad for the environment beyond the fuel, so it ads up for me.