AMP: 14 Location: Rockville Rd and Beach Pond Rd, Voluntown Reassurance shield after the 165 split. AMP: 16 Location: Rockville Rd and James Rd, Voluntown Reassurance shield halfway to the Rhode Island line. AMP: 16 Location: Rockville Rd and Spring St, Voluntown Welcome to Rhode Island! Route 138 continues as the longest state highway in … Continue reading Connecticut Route 138, CT 165 to RI-138/RI State Line