**4.2.1 Enhanced route planning**

In this application the infrastructure continuously collects information related to traffic density and makes forecasts for road segments with potential traffic jams. Then when an equipped vehicle drives next to a RSU the traffic density information on the neighboring area as well as driving instructions are transmitted to it. This information is processed by the vehicle and then the driver is informed about possible delays and alternative routes to avoid traffic jams. This way a significant number of drivers could be guided around congested areas so the entire transport system to become more efficient. A significant side effect of this application will be the reduction of pollution deriving from vehicles got stack in congested highways.

Figure 7 shows an enhanced route planning scenario in which the RSU informs the driver of the red vehicle about heavy traffic ahead and suggests a faster alternative route to the driver's final destination. It is obvious from the description of this application that for its implementation a RSU with wireless communication is essential to provide the necessary information. A vehicle equipped only with some perception sensors, without communication capabilities, could make a rough estimation about the traffic density in the road segment it is currently driving, but without any information on alternative routes.

Fig. 7. Enhanced route planning application.
