The two highways interchange with SH-3, a freeway at this point, near Ahloso. US-377/SH-99 merge onto the freeway, which becomes the Richardson Loop around the west side of Ada. At the southwest corner of the loop, SH-1 joins. Two miles (3.2 km) further north, an interchange serves as the western terminus of SH-19; also at this interchange, SH-3 splits into SH-3E and SH-3W, the latter of which exits the highway to concur with SH-19. At the next interchange, SH-1 splits off, and the freeway downgrades to expressway.