Several weeks ago, painted lines and flexible plastic lane dividers began materializing on Maryland Avenue, one of the major north-south arteries that connect downtown Baltimore to the residential neighborhoods above the city. The resulting 2.6-mile route is called a cycle track, one of the city’s first examples of fully protected bike infrastructure. This new two-lane bike highway eliminated a lane of automobile traffic and 15 parking spaces, to the disgruntlement of many motorists who used…