A lot of improvements have been taking place on this road. The next project to begin will be a pretty substantial project almost $1 billion in cost.
It be between SR-57 and SR-55. It will include some reconstruction, added lanes, and other improvements to reduce congestion:
https://octa.net/news/news-releases/sr-91-improvement-project-gets-underway-in-oc/?fbclid=IwZXh0bgNhZW0CMTEAAR1y_1bePZnVtSDHmy4XSy9xKDfLigdtZQElr3sJXKbb3wahvzTFNU8PwcQ_aem_sO3LNbl05EeOaASSbQE7qQ
Will the 91 Express Lanes be extended from CA 55 to CA 57? Perhaps the existing carpool lane could be converted to a toll lane all the way to Interstate 110.
Still no one dares to rebuild the CA-91 west to CA-55 south ramp to eliminate the left exit
But still it won't be enough, not with the rate Riverside County is growing.