  The requirements of vehicular communications grow with increasing level of
automated driving and future applications of intelligent transportation systems
(ITS). Beside the ever-increasing need for high capacity radio links,
reliability and latency constraints challenge the mobile network supply. While
for example the millimeter-wave spectrum and THz-bands offer a vast amount of
radio resources, their applicability is limited due to delicate radio channel
conditions and signal propagation characteristics. Reconfigurable intelligent
surfaces (RISs) as part of smart radio environments (SREs) of future ITS
infrastructure promise improved radio link qualities by means of purposeful
cultivation of passive reflections. With this, obstructed mmWave or THz beams
can be guided around obstacles through RIS reflection paths to improve the
otherwise limited coverage. In this article, application use cases of
RIS-enhanced vehicular communications are proposed. Beside static deployments
of RISs at exterior walls of buildings, unmanned aerial vehicles (UAV) could
provide reflection capabilities on demand, while future vehicles could - in a
visionary approach - consist of meta-material allowing for their opportunistic
utilization within an enriched SRE. Results of a case study based on our
multi-scale mobility and network simulation model clearly highlight the
potential of RIS deployment for hybrid vehicular communication scenarios. Path
loss and outage percentages can be reduced considerably.
