Note that ISTEA repealed the previous Federal-Aid System, effective in 1992, and established the functional classification system for all public roads.In 1963, this route was defined as running (a) Route 1 near Corona Del Mar to Route 405.In May of 1996, the California Transportation Commission declared the toll road a "freeway." In March 2016, the CTC allocated additional funds for a project on Route 73 in Laguna Beach in Orange County at the northbound collector/distributor from the El Toro Road on-ramp to the Laguna Canyon Road (Route 133) offramp.The project will widen the ramp and modify signals.In July 2007, the CTC relinquished right of way in the city of Costa Mesa, from the South City Limit to 0.4 mile North of Red Hill Avenue, consisting of reconstructed and relocated city streets.The City, by relinquishment cooperative agreement dated June 4, 2007, waived the 90-day notice requirement and agreed to accept title upon relinquishment by the State.Now, the toll road is being termed a freeway because it is under Caltrans control.
In 1983, Chapter 849 changed the origin of the route and modified the routing to be "Route 5 near San Juan Capistrano to Route 405 via the San Joaquin Hills." It also noted that "Mac Arthur Boulevard from Route 1 near Corona del Mar to San Diego Creek in Irvine shall cease to be a state highway when the Route 73 freeway as described above is completed." This reflected the planned construction of the San Joaquin Hills Toll Road. In 2003, Chapter 525 removed the text about the former portion of the route. The portion of the current routing from near UC Irvine to I-405 was LRN 184, defined in 1933 (as was the remainder of the since deleted 1963 routing) Route 73 was not defined as part of the initial state signage of routes in 1934.
In September 2011, it was reported that a request by the California Department of Transportation (Caltrans) to sign a freeway agreement related to the road that connects Newport Beach to Aliso Viejo was delayed at the Sept. Laguna Beach officials opposed construction of the roadway and much of the sentiment against it remains.
Route 73 was inherited by Caltrans from the Transportation Corridor Agency, which constructed it, but the standard freeway agreement was overlooked in the process, according to a Laguna Beach staff report.
The portion of this freeway between Mac Arthur Blvd and Route 405 was named by the "Corona Del Mar" freeway by the local Caltrans District.
The first freeway segment opened in 1977; the last segment in 1996.