The Federal Transit Administration (FTA) sponsored this research to assess both the appropriateness of its existing minimum service-life policy for transit buses and vans, and the need to change that policy. The research evaluated the federal minimum service-life requirements based upon the actual experience of both transit operators and vehicle manufacturers. The analyses in this research provide the transit industry and the FTA with a better understanding of (1) the current useful life of transit buses and vans, (2) the appropriateness of FTA’s minimum service-life policy, and (3) the policy’s impact on transit vehicle life expectancies and vehicle retirement decisions at the agency level. Actual ages of buses retired from service generally exceed FTA minimums. Transit agencies interviewed cited availability of capital funds for bus replacement as the primary determinant of retirement age.