Evaluation of vehicle structural durability is one of the key requirements in design and development process of commercial vehicles. Computer simulations are used to estimate vehicle durability because of its cost advantage and reduction in lead time to launch the product.The objective of this work is to find the service life of the passenger commercial vehicle (Bus) by calculating cumulative fatigue life in operation under actual road conditions. Chassis and superstructure were considered for this exercise. Measured road load data at vehicle wheel centers were used for performing multi-body simulation in ADAMS to extract load histories at attachment points. Modal transient response analysis is performed using MSC-Nastran with the extracted load time history. Strain based fatigue life analysis is carried out in MSC-Fatigue using modal superposition method (MSM). The estimated chassis and superstructure fatigue life is compared with the physical test results.