A limited-access Beltline allows you to drive uninterrupted through Middleton. In 1987, you got to take the scenic cruise along Parmenter Street. Additionally, there is no little open space for development west of the Beltline.
Source: oversized atlas of aerial views of Dane County (Madison Public Library)
Latest Google Maps view
North to South: Airport Road Business Park (east of Firefighters Park), University Green Business Park (left), Discovery Springs (right, but still west of the Beltline)
All you see is open space immediately to the west of the mostly 2-lane U.S. 12 as it slices through the western edge of Middleton and Madison, Middleton's business park in the northwestern section of the photo notwithstanding.
From south to north: Discovery Springs (Middleton), Greenway Station (Middleton), Old Sauk Trails Business Park (Madison, the development just getting underway).
Had this photo been taken a year earlier, the divided Beltline (U.S. 12) and Old Sauk Road intersection would not yet have been constructed. At that time, the Beltline narrowed to two lanes in the vicinity of Mineral Point Road.
Latest Google Map view
North of Old Sauk Road is Old Sauk Trails Office Park. South of Old Sauk Road is the Junction Ridge neighborhood and commercial/office district.