Described herein are embodiments that provide out-of-band authentication for vehicular communications using Joint Automotive Radar Communications (“JARC” if singular, “JARCs” if plural). A method includes receiving, by a directional radio of a connected vehicle, a directional communication having a payload that includes the first temporary identifier and sensor data for a purported transmitter of the directional communication. The method includes initiating, by the directional radio and a radar of the connected vehicle, a set of JARCs with the purported transmitter to determine an authenticity status of the first temporary identifier. The method includes executing a vehicular action for the payload of the directional communication responsive to the authenticity status.