[2] Friedlaender held appointments in two MIT departments as Professor of Civil Engineering and Economics for the class of 1941.
Friedlaender was also held positions off campus as a director of the Rand Corporation and of Conrail; a member of the American Economic Association, serving on the executive committee for two years; the chair of the Committee on the Status of Women in the Economics Profession (1978–1980; and an associate editor of Transportation Science for 14 years.
Friedlaender was a scholar who published many professional and academic articles, influential books, and several monographs.
One of the most well-known publications she wrote was The Interstate Highway System, which quickly made her an authority in the field of transportation economics at the age of 27.
Friedlaender's work with Spady, Transport Regulation: Equity, Efficiency, and Competition in the Rail and Trucking Industries, raised a lot of attention along with significant policy implications.
There, she actively provided help and was committed to inspiring more women to choose academic careers and attend graduate school.