The Arizona Department of Transportation (ADOT) operates a transportation library. The mission of the ADOT Library is to provide ADOT employees with the published information they need to carry out their job responsibilities contributing to a safe, efficient, and cost-effective transportation system in Arizona. Historically, ADOT's librarians have used professional judgment to decide which materials to add to the collection. This research is the first formal investigation to determine the information needs of ADOT staff and the role of the Library in meeting those needs. This study has provided information regarding: (a) the information needs of the ADOT staff, including the means by which they currently obtain the information they need; (b) preferences regarding access to Library services and resources; and (c) awareness and use of the ADOT Library. Findings from the study also provided insights into the role of transportation libraries, the extent to which ADOT Library practices align with acknowledged effective practices in transportation libraries overall, and opportunities for ongoing improvement and enhancement of Library operations, communications and marketing efforts, customer service, and valuation. Recommendations were developed to facilitate delivery of ADOT Library services in fiscal periods characterized by severe budgetary constraints and limited resources as well as in less constricted fiscal periods permitting continued investment in ADOT Library resources (staff, collection materials, information technologies). The research findings can be used by ADOT to inform strategic and contingency planning efforts and will enable ADOT to make data-driven decisions regarding the Library collection and services.