Side glass soiling due to A-Pillar overflow is a growing challenge for automotive manufacturers. Pressure to remove traditional vehicle features, such as A-Pillar steps, to achieve lower drag targets has meant that A-Pillar overflow has become more common. A-Pillar overflow, however, can be a major concern if important regions of the side glass are affected. The ability to predict where and under which conditions the A-Pillar will overflow is important for making correct design decisions. The development of a numerical simulation solution is desirable as experimental testing requires a late stage prototype, making it very difficult and costly to correct problems. This paper provides an update on the ability of simulation to predict A-Pillar overflow, comparing simulation and numerical results on a test vehicle. These results include both with and without wipers, as the presence of wipers was found to impact the A-Pillar overflow in the experiments. In addition to showing the agreement between experimental and simulated results, this study will investigate the mechanisms responsible for A-Pillar overflow, examining why A-pillar breaching occurs at specific locations.