In this work, the flow velocity distribution was determined by measurements of visualized flow, obtained with a one-fourth scale three-dimensional model, and by numerical analysis. The measurements of interior flow were obtained using a method which combined the particle-tracking technique, a basic method conventionally employed for flow visualization, with a pulsed-laser-light-sheet technique. Flow images taken with a video camera were then processed by means of an image processing system. Flow velocity distributions were obtained for two different discharge modes - a dashboard-vent mode in which air was discharged from four vents provided along the top of the dashboard, and a bi-level mode in which vents at the foot position were added to those of the first mode. Three-dimensional numerical analyses using a direct-simulation method were conducted to calculate the interior flow, and a comparison was made with the measured results obtained in the visualization experiment.