One distinguishes between Car-to-Car and Car-to-X. The former means the communication between the cars themselves, the latter, the communication between the car and a fixed point, e.g., one built into a traffic light or one provided by a manufacturer. In the meantime it's insides are very interlinked. The advantages are exploited with newer and newer software or ever appearing new assistants. Now one would also like to create synergies beyond the confines of the car. We experience parts of this daily, e.g., when once again, the subject of autonomous driving is raised.
One thing is certain, the external interlinking of cars will come earlier and, e.g., as the videos on this page show, hopefully also point the way to fewer road accidents. Experts are of the opinion, that the technical requirements have just recently been achieved. Since for two message inputs, the one which continuously flows in, and the other, then when a dangerous situation threatens, have made progress in leaps and bounds, a new high performance software is needed. The biggest concern is, that once again, a backdoor for unwanted hacker-activities may be thus opened.
That which is already running smoothly, is the necessary exchange with commercial areas, who have already gathered more know-how in this field. Ever since the invention of the CAN-Bus, one rather has the impression, that other branches are using the tried and tested and also unbeatably reasonable BUS-systems, originating from the motor vehicle technology. These now have to learn, perhaps from the cell-phone industry or others who have experience in the field of wireless networking. The aviation field could provide a good example, which can only be looked at with envy by those developing autonomous driving.
Indeed, before one can feed information into the network, one has to first acquire the information oneself. What's more, this information also has to be reliable. Now, what is important as the basis of a warning to others? The location, i.e. exactly where one is. This is also the first thing that must be ascertained in an accident call. Another important thing is, that this information must not only be precise but also understandable for other systems. Satellite-systems are not always reachable, e.g., in a 'dead-spot'. This is why there must always be at least one complementary system, that can process the location data acquired from the vehicles sensors.
Indeed, this is not enough. Should one wish to send processed data Car-to-Car, then one can use this system beforehand, to check the calculations and the received satellite-data determining one's own position. This also works with Car-to-X and presumably, also with pedestrians who are carrying a cell-phone, which apparently also reacts if the phone is switched off. By the way, particularly these road users belong to a group who are to be especially protected by the system. Just recently, one has been considering including other inanimate objects in the internet process. School-bags, e.g., may be worth thinking about.
The factor that is desperately lacking, is the third dimension, the height. Some may consider it to be not all that important, but it simply belongs to the positioning. I was standing in front of the fair-gate in Frankfurt, where I wanted to be however, was in front of the one exactly opposite, it took a lot of steering wheel work before I had corrected the error. What could help in the future, would be more precise maps. Perhaps a new system for the storage of such data is what's needed. In the meantime at least, one is pin-pointed to within about 10 meters. You can imagine, that with this low degree of accuracy, no field can be cultivated and no braking distance can be calculated. 12/14