This paper discusses the use of Extreme Value Analysis Technique for determining vehicle extreme service loads in service. A statistical method is presented (1) to estimate long term most severe loads in service from short term measurements, and (2) to estimate the multiple circuit proving ground loads from a few measured circuits. A procedure is also discussed for determining the minimum required trip time for recording load data (short term) so that the data have a statistically valid base for long term projection. Actual strain/time histories were measured for several structural components in “service-run-like” environment. Two thousand kilometers of run were recorded, the data were analyzed and the results presented. A detailed theoretical discussion on the extreme value distribution function is given in the Appendix.