Vehicle to vehicle WiFi communication is standardised under the 802.11p and 802.11bd ammendments. They main difference between 11p and standard WiFi is they have halved the bit rate to increase the range and provide a way for vehicles to broadcast info outside a pre-established network context. 11bd builds on 11p adding more functionality. I don't remember the specifics of 11bd as at the time I was working with the technology 11bd hadn't finished standardisation yet.

11p and 11bd are more generally V2X comms of which there are a cellular variants (C-V2X and NR-V2X)