The extension of Interstate 40 through Bakersfield to U.S. 101 is long overdue; one proposed route I saw in the early 1990's would have jogged up the San Joaquin Valley on I-5 to Lost Hills, then along CA. Hwy. 46 through Cholame to 101 at Paso Robles. I drove this route many times in the early 1990's. It is very busy with Ag traffic out of Salinas; too busy for a mostly 2 lane state highway in my opinion.
I agree that Hwy. 152 over Pacheco Pass is a poor road, except for the new part around San Luis Res., paid for by the State Water project. I wonder of the water project engineers knew ( or cared ) how close San Luis Res. and Pyramid lake are to the San Andreas Fault ???