I feel the sound -> stress connection palpably. Especially sudden loud noises like a horn honking cause me to feel upset for a long while after being startled. Seems like a convincing argument to me for car-free spaces, although honestly I just wish we had stronger social norms against unnecessarily using a car's horn.
Fun thing is, when I am in the city, I like opening the windows in summer and car noises don't bother me much because it's normal and part of the scenery.
But then I am perfectly capable of putting on my pajamas past 10PM, climb down the stairs from the flat to the street, knock on the car's window and ask the driver to turn off the engine because the low humming noise I hear in my bed is driving me insane. It's when the sound is useless and could be easily prevented that I get crazy. Misophonia very much also.