In order to make vehicle testing on test stands more realistic, environmental factors including changes in altitude, have to be taken into consideration. A change in altitude results in changes in air pressure and temperature, which will influence the vehicle’s behavior regarding emission output, fuel consumption, wear of components and decrease of maximum power and torque. Determining and measuring this influence in real road tests is cost-intensive as well as time-consuming since test routes with high changes in altitude are very limited and the test conditions may vary depending on the geographic location and time of the year. During development oftentimes the better solution is to test and optimize the vehicle on a chassis dynamometer and afterwards confirm these simulated tests under real driving conditions. Therefore, an altitude simulator is used in combination with a chassis dynamometer to carry out altitude simulation tests of vehicles in test cells. Altitude chambers have been used in the past, but offer less flexibility in usage.