By the early 1990s, the El Toro Y had become one of the most congested freeway interchanges in the world, its severe overcrowding fed by a housing boom in southern Orange County. In November 1990, Orange County voters approved Measure M, a half-cent increase in the county sales tax to finance transportation improvements. In 1993, the California Department of Transportation began a massive expansion project, adding a new interchange and collector/distributor roads at Bake Parkway and Lake Forest Drive, and carpool lanes and connectors. The $166-million project also vastly increased regular traffic lanes. The project increased the number of vehicles per day from 300,000 to 400,000. After the project was completed in 1997, the El Toro Y stood as one of the widest roads in the world, at 26 traffic lanes wide. The traffic delays at the interchange sparked the construction of several parallel bypass toll roads. The San Joaquin Hills Toll Road, designated State Route 73, opened in November 1996 and connects San Juan Capistrano and Costa Mesa. Another parallel road to the El Toro Y is SR 241, the Foothill Toll Road, which is planned to include a southern extension known as "Los Patrones Parkway" that will end near SR 74. Originally, the route was supposed to connect to I-5 in northern San Diego County, but local opposition regarding environmental issues near Trestles have put the project on hold. In 2017, the Transportation Corridor Agencies considered extending this route to San Clemente. However, residents opposed the proposed route because it would have cost $2 billion, would have intersected at the busiest interchange in San Clemente, Avenida Pico, would have demolished many new homes with real estate value, would have been constructed next to a high school, and would waste taxpayers’ money because the interchange had undergone improvements between 2015 and 2018. Local residents also say that traffic would be worse, equivalent to the SR 91 and SR 241 interchange. The Irvine Spectrum Center, a large shopping center featuring a movie theater, numerous shopping destinations and a large obelisk, which conceals a cell phone and television tower inside of it, is in the cleft of the Y. On July 29, 2008, a moderate earthquake centered in Chino Hills caused damage to an expansion joint on one of the overpasses in the interchange. Caltrans closed the 5 Southbound Truck Bypass/Bake Parkway/Lake Forest exit to replace the expansion joint that was damaged during the quake.
The El Toro Y was referenced in an episode titled of the animated sitcom The Simpsons, when Bart gives Homer a list of "Must-See Attractions" in Los Angeles. In the second episode of, it was initially reported that O. J. Simpson was spotted in Al Cowlings's Ford Bronco on Interstate 405 at Irvine Center Drive at the El Toro Y. However, the scenes were shot elsewhere in Los Angeles.
