The six-lane Arroyo Seco Parkway (part of State Route 110) begins at the Four Level Interchange, a symmetrical stack interchange on the north side of downtown Los Angeles that connects the Pasadena (SR 110 north), Harbor (SR 110 south), Hollywood (US 101 north), and Santa Ana (US 101 south) Freeways.
As the original freeway begins, it passes under an extension to the 1925 Avenue 26 Bridge, one of four bridges over the Arroyo Seco that predate the parkway's construction.