(credit: US Department of Transportation)

Nearly three years after it was first mooted, the National Highway Traffic Safety Administration published a Notice of Proposed Rulemaking on Tuesday that will mandate vehicle to vehicle (V2V) communication systems in all new cars and trucks. Once the rule is finalized, car makers will have two model years to begin including V2V systems, with some added leeway for product cycles. V2V-equipped cars will communicate with each other at short ranges to prevent the kinds of accidents where current advanced driver assistance systems, most of which depend on line of sight, aren’t effective.

V2V, and the related vehicle to infrastructure (V2I), relies on the Dedicated Short-range Radio Communication (DSRC) wireless protocol to communicate between devices at ranges of up to 984 feet (300m). Vehicles will be able to send out standardized “basic safety messages” that trigger driver alerts or even emergency avoidance actions to prevent crashes. (For a more detailed explanation of how V2V works, check out this piece from Ars’ Sean Gallagher.)

Recognizing the immense implications of an insecure protocol, the notice asks industry and the public for input on the proposed security specifications and proposes that “vehicles contain “firewalls” between V2V modules and other vehicle modules connected to the data bus to help isolate V2V modules being used as a potential conduit into other vehicle systems.” Privacy is also given due attention, and the proposed rule would prevent cars from sending out identifiable data like a vehicle’s VIN or a driver’s name or address.