The previous studies in the series of which this study is a part focused mainly on individual intersections where traffic congestion or safety problems do not extend to other locations. This study focused on large single intersections and sets of adjacent intersections on the region’s arterial roadways where many crashes occur and there is extensive congestion during peak periods. Four intersections were studied: one in Southborough, one in Wilmington, and two in Quincy. MPO staff selected these locations using a process involving extensive data screening and numerous interactions with MassDOT Highway Division District offices and city and town governments. Staff performed safety and operations analyses and developed recommendations for improving the selected intersections’ operations and the safety of drivers, bicyclists, and pedestrians at these locations. Three memoranda, one for each municipality, present the analyses and recommended improvements.