The United States Department of Transportation established the Disadvantaged Business Enterprise (DBE) program to ensure nondiscrimination and fair competition on federally assisted contracts for all enterprises. Although DBE programs set DBE participation goals and offer supportive services, DBEs are rarely successful and still experience significant participation barriers, performance impediments, and development hindrances. With limited studies focusing on DBE success, the author investigated multiple interdisciplinary studies for the success of DBEs in the transportation sector. The author used qualitative, quantitative, mixed, and multiple methods in these studies. The quantitative data was collected from DBEs nationwide, DBE directories, DBE program websites, and national databases. The qualitative data was collected from DBEs and DBE liaison officers who were willing to participate in a particular research study. These studies began with describing characteristics of DBE firms and practices of DBE programs. Then, the author identified DBE challenges using both variable clustering technique and principal component analysis. Next, the author proposed a framework for providing supportive services in business, engineering, construction, and other (BECO) categories. The BECO framework revealed useful supportive services to DBEs in construction contracting, engineering consulting, and other business areas. Last but not least, the author summarized common DBE fraud and abuse schemes such as front, pass-through, fabrication, and false claims. Although these studies have limitations, the outcomes provide an understanding of DBE firms and DBE programs, inform policymakers on future regulatory changes, and improve both the experience of DBEs and the quality of DBE programs.