  5G Vehicle-to-Everything (V2X) is a promising technology to satisfy the
increasing demands of intelligent transportation systems. Emerging V2X
applications with a high level of automation impose very strict requirements on
latency (less than 10 ms) and reliability (higher than 99.99%). For sporadic
traffic, such demands can be satisfied with a distributed channel access method
called Mode 2. This letter proposes an analytical model of Mode 2 that
estimates the packet loss rate and the network capacity taking into account the
peculiarities of Mode 2 and -- in contrast to the existing models -- provides
the accuracy required in the emerging V2X scenarios. The model can be used to
find the optimal transmission parameters that maximize the network capacity
and/or to select the required bandwidth.
