  In future 6G millimeter wave (mmWave)/sub-THz vehicle-to-everything (V2X)
communication systems, vehicles are expected to be equipped with massive
antenna arrays to realize beam-based links capable of compensating for the
severe path loss. However, vehicle-to-vehicle (V2V) direct links are prone to
be blocked by surrounding vehicles. Emerging metasurface technologies enable
the control of the electromagnetic wave reflection towards the desired
direction, enriching the channel scattering to boost communication performance.
Reconfigurable intelligent surfaces (RIS), and mostly the pre-configured
counterpart intelligent reflecting surfaces (IRS), are a promising low-cost
relaying system for 6G. This paper proposes using conformal metasurfaces
(either C-RIS or C-IRS) deployed on vehicles' body to mitigate the blockage
impact in a highway multi-lane scenario. In particular, conformal metasurfaces
create artificial reflections to mitigate blockage by compensating for the
non-flat shape of the vehicle's body, such as the lateral doors, with proper
phase patterns. We analytically derive the phase pattern to apply to a
cylindrical C-RIS/C-IRS approximating the shape of the car body, as a function
of both incidence and reflection angles, considering cylindrical RIS/IRS as a
generalization of conventional planar ones. We propose a novel design for
optimally pre-configured C-IRS to mimic the behavior of an EM flat surface on
car doors, proving the benefits of C-RIS and C-IRS in a multi-lane V2V highway
scenario. The results show a consistent reduction of blockage probability when
exploiting C-RIS/C-IRS, 20% for pre-configured C-IRS, and 70% for C-RIS, as
well as a remarkable improvement in terms of average signal-to-noise ratio,
respectively 10-20 dB for C-IRS and 30-40 dB for C-RIS.
