Summary: The Army's modernization of its fleet of medium tactical vehicles, at a projected cost of $15.7 billion, is one of the Army's largest acquisition programs. From 1991 through 2022, the Army plans to buy more than 85,000 trucks to replace its aging fleet of medium trucks. The new trucks, part of the Family of Medium Tactical Vehicles (FMTV), are 2.5- and 5-ton trucks based on a common truck cab and chassis. GAO found that the Army's plans for implementing its follow-on production contracts need to ensure that the government receives trucks that meet FMTV program standards. The current contract allowed the contractor to produce trucks even though they were unable to pass testing and show that they met performance and reliability, availability, and maintainability standards. These trucks required modifications to achieve satisfactory performance that caused program delays. In addition, the Army relaxed its final acceptance inspection method from a 100-percent inspection to a sampling inspection method without validating that the contractor's production processes ensured that the trucks met quality standards. Recent government inspection data and quality deficiency reports on trucks in the field show that the contractor is not consistently producing trucks with the quality standards set for FMTV trucks. The Army plans to compete future procurement of these trucks with the expectation that program costs can be reduced. Therefore, it has decided to develop a second source to produce the trucks. The current contractors and second source will share the annual production. However, the Army has not determined the costs and the benefits of this plan or compared it to other alternatives. GAO's preliminary analysis of the production quantities that the two contractors could expect to share from the competition indicates that the Army's plan may not yield cost savings.