Abstract: A vehicle with a ventilation system that includes a chassis and vehicle body. The vehicle body is mounted on the chassis, and has a floor, a ceiling, a front section, and a back section. The front section includes control instrumentation and an adjacent driver seat. The front section further defines a vent opening and has a duct mounted on the ceiling. The duct extends from the vent opening, and has at least one air portal structured and arranged to direct air over the driver seat. The duct includes a main passage and projections, which are partially defined by sloping walls so as to provide a region of less constrictive air flow as compared to an intake passage. The intake passage extends upward from the vent opening to inhibit moisture from entering the main passage, and the projections and slope of the intake passage serve as a conduit to drain away any moisture that does manage to enter the main passage.