High Quality Content by WIKIPEDIA articles! New Mexico State Road 556 is a 15.7 mi (25.3 km) long state highway entirely within Bernalillo County, New Mexico. For most of its length, NM-556 is signed as Tramway Boulevard in Albuquerque, paralleling the Sandia Mountains. The highway`s southern terminus is at an intersection with New Mexico State Road 333, or Central Avenue. The highway then moves north intersecting with Interstate 40. The highway is a divided four-lane road until its intersection with Tramway Road. After that, the highway narrows to two lanes and takes a westerly turn to intersect with Interstate 25. The highway`s northern terminus is at an intersection with New Mexico State Road 313 and New Mexico State Road 47.