This one is not your typical bonafide "egg" but I feel it's a good mention because the reference seems to be lost on the vast majority of people I tell about it.

In San Fierro there is a broken up stretch of neglected double-decker freeway running parallel to the interstate entering onto the Garver Bridge. This is a direct representation of the aftermath of the Oct. 17, 1989, Loma Prieta Earthquake that shocked San Francisco. There were 67 deaths with 3,757 injured.

The most famous incident was the collapsed Cypress Street Viaduct on the Nimitz Freeway (I-880). 40 of the 67 dead were here - likely the reason for the flowers planted near the site by Rockstar.