Waze

Waze is a navigation app built on crowdsourced reports: drivers flag accidents, police, road closures and hazards, and routing updates from what other drivers are actually experiencing.

That makes it strongest exactly where static map data fails — sudden congestion, temporary closures and incidents that no map has yet recorded.

Its value depends on user density: in cities with many active users it routes better than alternatives, and in sparsely covered areas it offers little advantage.