Ground-moving target indicator (GMTI) radar, commonly deployed on airborne platforms, is currently precluded on surface vehicles due to multipath spread-Doppler clutter in complex terrain. Multiple-input multiple-output (MIMO) radar techniques have been shown to successfully mitigate spread-Doppler clutter in other radar applications, such as over-the-horizon (OTH) radar. In the instance of a forward-looking, vehicular-mounted GMTI radar, MIMO spacetime adaptive processing (STAP) techniques have been shown to mitigate multipath clutter resulting from a point reflector and the ground. However, fully adaptive MIMO STAP uses a large number of degrees of freedom, which requires an immense amount of training data to support. In addition, a single point reflector is not an accurate representation of an urban environment. This research explores using partially adaptive MIMO beamforming techniques with a significantly reduced number of degrees of freedom than fully adaptive MIMO STAP, in the situation of a forward-looking, vehicular-mounted GMTI radar in the presence of a large specular reflector, such as a highway guardrail or a building wall. (5 pages)