The radio system for the V2V Communication
is derived from the standard IEEE 802.11, also
known as Wireless LAN. As soon as two or
more vehicles are in radio communication
range, they connect automatically and
establish an ad hoc network. As the range of a
single Wireless LAN link is limited to a few
hundred meters, every vehicle is also router
and allows sending messages over multi-hop
to farther vehicles. The routing algorithm is
based on the position of the vehicles and is
able to handle fast changes of the ad hoc
network topology. In the below picture (fig. 1)
we can see that oil is there on the express
highway and the a vehicle got slip due to it,
this movement is caught by the system and
emergency warnings are send to other vehicles
about the danger, it even controls the speed of
the vehicle to avoid accident.