 South Rolling Road was constructed as a state highway by the early 1920s between what were to become U.S. Route 1 and US 40.Parts of South Rolling Road were transferred to county maintenance after they were severed by the construction of I-95 and a freeway relocation of the southern end of MD 166 in the early 1970s.MD 166 begins as a continuation of the four-lane Metropolitan Boulevard freeway at the northern terminus of I-195 just north of the Interstate's interchange with I-95.