According to the European commission (Road Safety Evolution in EU, 2009), 1.2 million road accidents took place in the European Union in 2007. These road accidents have resulted in 1.7 million injuries and more than 40 thousand deaths. It turned out that human errors were involved in 93% of these accidents. V2V communication is a key element in reducing road casualties. For the development of future V2V communication systems, the exact knowledge of the statistics of the underlying fading channel is necessary. Several channel models for V2V communications can be found in the literature. For example, the two-ring channel model for V2V communications has been presented in . There, a reference and a simulation model have been derived starting from the geometrical two-ring model. In (Zajić et al., 2009), a three-dimensional reference model for wideband MIMO V2V channels has been proposed. The model takes into account single-bounce and double-bounce scattering in vehicular environments. The geometrical street model (Chelli & Pätzold, 2008) captures the propagation effects if the communicating vehicles are moving along a straight street with local roadside obstructions (buildings, trees, etc.). In (Acosta et al., 2004), a statistical frequency-selective channel model for small-scale fading is presented for a V2V communication links. The majority of channel models that can be found in the literature rely on the stationarity assumption. However, measurement results for V2V channels in (Paier et al., 2008) have shown that the stationarity assumption is valid only for very short time intervals. This fact arises the need for non-stationary channel models. Actually, if the communicating cars are moving with a relatively high speed, the AoD and the AoA become time-variant resulting in a non-stationary channel model. The traditional framework invoked in case of stationary stochastic processes cannot be used to study the statistical properties of non-stationary channels. In the literature, quite a few time-frequency distributions have been proposed to study non-stationary deterministic signals (Cohen, 1989). A review of these distributions can be found in (Cohen, 1989). Many commonly used time-frequency distributions are members of the Cohen class (O'Neill & Williams, 1999). It has been stated in (Sayeed & Jones, 1995) that the Cohen class, although introduced for deterministic signals, can be applied on non-stationary stochastic processes. In this chapter, we present a non-stationary MIMO V2V channel model. The AoD and the AoA are supposed to be time dependent. This assumption makes our channel model non-stationary. The correlation properties of a non-stationary channel model can be obtained using a multi-window spectrogram (Paier et al., 2008). For rapidly changing spectral content however, finding an appropriate time window size is a rather complicated task. The problem is that a decrease in the time window size improves the time resolution, but reduces the frequency resolution. To overcome this problem, we make use of the C...