Abstract
The project was carried out to determine the likely infiltration rate of a gas into a stationary motor vehicle for different wind speeds and directions. Measurements were first made on five vehicles under both positive and negative pressures to determine their leakage characteristics both with the vents open and with them closed. A tracer gas method was then used to determine the air change rates in the vehicles for different wind speeds and directions. In the second part of the project the scenario considered was that of a vehicle moving through a cloud of contminant. Measurements of air change rates (ACH) were made on a vehicle driven at constant speeds of between 35 and 70 mph (15 and 32 m/s).