The environmental impact of snowmobile noise has received widespread publicity over the past few years. In order to define and solve any noise problem, a satisfactory and repeatable measurement practice must be evolved. In the case of SAE J192, the particular operating environment of snowmobiles proves a challenge to this task. Environmental conditions affect not only the propagation of sound at the test site, but also the performance of the vehicle itself. This results in a potential for significant variation in the sound pressure level of the sound source. Hence, the test procedure must be designed so as to minimize if not eliminate such sources of variations.