## 5 International Roadmap to Mandate Connectivity on Board
### When Connected Devices Will Be on Board  
From the above sections about the roadmap of mandatory rules all around the world, it is clear that there are still no fixed regulations or mandatory rules about the integration of connectivity on board and that, in general, none of the mentioned Countries specifically indicate which technology should be used (even if it seems that the US are favorable to IEEE and EU mentions 5G connectivity for the first time in [50]). Independently from the rules, it is also interesting to understand how car makers are moving. The only commercially available on board unit (OBU) and road side unit (RSU) devices are based on IEEE 802.11p standard and some car makers are considering starting installations on board.  
Many carmakersare starting to introduce V2V communication in their vehicles. Toyota announced plans to begin a broad deployment of V2V and V2I communications based on IEEE 802.11p in the US market from 2021 [53]. Toyota was the first automaker to deploy V2V communications in Japan beginning in late 2015. To date, more than 100,000 Toyota and Lexus vehicles with V2V have been sold there, whereas Cadillac (General Motors group, New York, NY, USA) has sold barely one-tenth that many Cadillac CTS sedans. Among the first vendors integrating V2V on board there is also Cadillac. In its Cadillac CTS, Cadillac declared that it would use IEEE 802.11p and global positioning sensors to communicate with other vehicles on the road sending thousands of messages per second to other cars within a distance of 300 m [54]. Messages share vital information, such as traffic conditions, speed, position and direction, but the system does not share any private information or recognizable details since firewalls and encryption ensure the users' full privacy. In June 2017, Volkswagen declared that it would enable vehicles to communicate with each other as of 2019, integrating IEEE 802.11p as well [55]. When it is launched in 2019, the system will be based on warnings and information on local traffic risks that arise at short notice. In addition, Mercedes-Benz (Stuttgart, Germany) already equip, on request, its vehicles with the Drive Kit Plus to enable V2X communication all model series. Audi AG (Ingolstadt, Germany) has completed development of integrated V2X roof antennae. The series-production ready smart antenna contains an entire V2X solution, including radio and modem, global navigation satellite system (GNSS) antenna and receiver, V2X protocol stack and security, vehicle connectivity and V2X application matching ETSI Day-1 profile [56].  
In contrast, Ford (Dearborn, MI, Stati Uniti) announced plans to use C-V2X and, in partnership with Qualcomm and Datang (in Beijing, China), has been testing C-V2X devices since 2017, but since commercial devices are not still available, Ford has not yet committed a launch date [53]. Extensive testing to validate CV2X radio performance was initiated in 2017 in Ann Arbor, San Diego, Aberdeen and Shanghai. A trial with C-V2X was announced in Japan on January 12, 2018 in cooperation with Continental (Hannover, Germany), Ericsson (Stockholm, Sweden), Nissan (Yokohama, Japan), NTT DOCOMO (Tokyo, Japan), OKI (Tokyo, Japan) and Qualcomm Technologies, but, to the best of our knowledge, no other communications have been done after that [57].  
However, given the still limited number of equipped vehicles, with which cars can they actually talk to? The low penetration and the absence of a road infrastructure are the limit of equipped cars today and managing the transition toward a full penetration is not simple. Mandatory rules and suitable business models could represent a real motivation for manufacturers to move forward in an efficient way, equipping a critical mass of vehicles that otherwise would take many years to develop.