CheckPointz allows you to post the location and description of accidents, roadwork, or other physical barriers on the road that lead to traffic jams and delays.
If you see another persons point on the map and can visually confirm it, you will extend the life of the traffic stop or bottleneck.
Each traffic point lasts 120 minutes from when it was last confirmed. You can gauge how likely how bad the traffic will be by the number of people confirming it.