The state canceled plans to extend the freeway segment south, and the southern part of the road remains an undivided highway.

After entering the canyon, which lies between Laguna Coast Wilderness Park (west side of SR 133) and Aliso and Wood Canyons Wilderness Park (east side of SR 133), the first major intersection is with El Toro Road (CR S18).

After crossing I-5, SR 133 becomes part of the Eastern Transportation Corridor along the northwest side of Orange County Great Park (built on the site of the decommissioned Marine Corps Air Station El Toro), crossing an interchange with Irvine Boulevard at exit 12 before ending at SR 241.

[17] Widening of the part north of SR 73 to a four-lane expressway was completed in late 2006, moving the road out of the canyon bottom and allowing better access to areas in Laguna Coast Wilderness Park.

[17] The Eastern Transportation Corridor, which includes SR 133 north of I-5, was completed on October 15, 1998, opening a new shortcut from Orange County to the northeast.

As of July 2024[update], the standard two-axle car toll for both the northbound offramp and southbound onramp of Irvine Boulevard is a flat rate of $2.20.

[26] Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, based on the alignment that existed at the time, and do not necessarily reflect current mileage.