Not sure about that; I seem to recall the exact same situation in the 90s, before any apps: major street blocked, adjoining minor streets become clogged with ca

Not sure about that; I seem to recall the exact same situation in the 90s, before any apps: major street blocked, adjoining minor streets become clogged with cars trying to get around that. But I think I see your point now: Waze amplifies the problem an order of magnitude. Still not sure that maintaining a list of "undesirable" streets is a good idea, but maybe discouraging the routing algorithm from taking side streets might work? (Seems to work around here - perhaps also a matter of map data quality?)