Supporting safety critical applications is at the core of car-to-car communication.
DSRC was developed to meet all V2X requirements. It is the incumbent V2X technology, with huge planned investments in infrastructure. Moreover, the USDOT is in the process of mandating DSRC in all new vehicles. Vehicles with DSRC-based V2X can be bought today from GM and Toyota, and Volkswagen announced a plan for mass-market deployment starting 2019.
Recently, C-V2X, a technology still in the making, is promoted by the cellular industry. No C-V2X products are available today, and are far from reaching the maturity and security levels needed for critical safety systems.
C-V2X introduction contradicts the notion of a large network of interoperable vehicles. Having a vehicle from one manufacturer not capable of communicating with a vehicle of another manufacturer is a major safety risk.
DSRC is more cost effective than C-V2X, since the latter is a costly and complex technology, rooted from base-station implementation. C-V2X is using a multi-user receiver requiring a 0.1ppm clock source. Moreover, C-V2X and cellular modem are expected to work concurrently but cannot share resources to reduce cost as a shared network will create a cybersecurity risk.
In addition, C-V2X struggles to meet the specific application requirements of car-to-car communication as detailed in the whitepaper, co-written by Autotalks and NXP: Download the full DSRC vs C-V2X comparison white paper.
the regulatory environment supports this view. Using C-V2X instead of DSRC in US or Europe is practically impossible.
For detailed analysis please find the full interview here: Insight on the V2X regulatory activity with Autotalks CTO, Onn Haran