md 175's first divided highway section was created when the highway was relocated from us 1 to just north of the modern md 108 intersection in conjunction with the construction of the i-95 interchange in 1969 and 1970. the state highway's interchange with us 29 in columbia was built in several stages. the westbound and eastbound bridges across the little patuxent river were built in 1970 and 1974, respectively. the first parts of the interchange to open were the ramps between county-maintained little patuxent parkway and southbound us 29. md 175's bridges over us 29 were built in 1974. the interchange fully opened when the new little patuxent parkway was completed from the existing highway at the present md 108 interchange west to us 29 in 1977. the portion of md 175 north of the new highway was replaced by an eastward extension of md 108 and md 104. the highway's trumpet interchange with columbia gateway drive opened with little patuxent parkway. md 175 was two lanes from us 29 to columbia gateway drive until the road was expanded to a divided highway in 1987. the highway's interchange with snowden river parkway was constructed in 2001. md 175's roundabout in odenton was installed in 2004.