So if I'm understanding this correctly, you had the device set to let in ambient sound, but a motor vehicle slamming on the brakes was filtered out, and you consider this to be a good thing? Sounds dangerous to me.
It was still audible, but filtered from 'damagingly painful' to 'perceptible', and only on the side that was directly exposed. I don't find a lot of navigational value in listening to someone's poorly maintained brakes while I'm walking around.
