ate last year, Google Maps started testing Waze-like incident reporting. The feature started with only crash and speed trap reporting. Shortly thereafter it rolled out widely and now pretty much everyone has the ability to report incidents while navigating. Google is adding a new type of incident to the reporting feature: traffic slowdowns.
Google Maps already indicates the flow of traffic with road colors. Users know if the road is highlighted in orange or red that traffic is moving slow. It could be for a variety of reasons. Google Maps will automatically take you on a different route if traffic is really bad. However, it can be slow to update sometimes. So why not let users help?
To report a traffic slowdown (or a different incident), tap the chat bubble icon while in navigation mode. You will have the option to select Crash, Speed Trap, or Slowdown. Devices set to UK English will display Slowdown as “Congestion” and users in India do not have the Speed Trap option.
Source: https://www.xda-developers.com/google-maps-traffic-slowdown-reporting/