  Reconfigurable intelligent surfaces (RISs) assist in paving the way for the
evolution of conventional vehicular networks to autonomous driving. Having said
that, the 3rd Generation Partnership Project (3GPP) faces numerous open
challenges concerning the RIS-aided vehicle-to-everything (V2X) solutions of
the near future. To tackle these challenges and to stimulate future research,
this article focuses on the prospective transmission design of RIS-aided V2X
communications. In particular, two V2X sidelink modes are enhanced by
exploiting RISs and their variants, followed by a customized transmission frame
structure that partitions the transmission efforts into different phases. Next,
effective channel tracking and resource allocation techniques are developed for
attaining a high beamforming gain at low overhead and complexity. Finally,
promising research topics are highlighted and future 3GPP standardization items
are proposed for RISaided V2X systems.
