Hazards can be defined by anything from someone moving into your lane, to there being an accident ahead.
If something like this happened, the system would automatically detect it and then display a warning.
Here is an example of a warning when someone moves into your lane ahead of you.

The image above is highlighted in a sharp red, however for something not as serious as a car coming into your lane it wouldnt be as sharp. This colour would be for something like an accident or immediate danger.
The system would also monitor the traffic through a 3G feed, so it could notify if the driver if the traffic was particularly heavy in an oncoming area. It would then work with the GPS to deliver a work around route.
The system would also monitor the traffic through a 3G feed, so it could notify if the driver if the traffic was particularly heavy in an oncoming area. It would then work with the GPS to deliver a work around route.