Interstate highway construction slowed dramatically in the 70s after federal funds largely dried up except for the remaining critical arteries like the Colorado I70. Since then, a dozen highways proposals have come and gone because of eminent domain and environmental impact lawsuits in Southern California alone.
The I710 expansion, for example, was finally axed a few years ago after six decades of opposition from South Pasadena and the surrounding cities. At one point the state was considering a plan to tunnel under the town for about a $billion a mile because the opposition was so intractable (well funded and connected) before Caltrans gave up and started selling all the housing they'd been accumulating for decades for the project.
The I710 expansion, for example, was finally axed a few years ago after six decades of opposition from South Pasadena and the surrounding cities. At one point the state was considering a plan to tunnel under the town for about a $billion a mile because the opposition was so intractable (well funded and connected) before Caltrans gave up and started selling all the housing they'd been accumulating for decades for the project.