It's not just about emissions. The entire character of the area changes. The streets fill with pedestrians and bicycles. Garbage trucks and ambulances still us

It's not just about emissions. The entire character of the area changes. The streets fill with pedestrians and bicycles. Garbage trucks and ambulances still use the streets. But they face no traffic and are exceptions rather than the rule. They don't need to be either low emission or quiet, though those things are also nice to have, since those things are no longer the most pressing issues.