I-5 between Sacramento and LA is designed for 70-80 mph in a well-maintained passenger car. It has too many trucks for anybody to come near that as an average, though >100 mph is commonly seen in spurts (and, note to CHP, on Sunday mornings). I-5 has many kinks; to be a good HSR alignment it would need to be realigned (at a significant cost to agricultural land around it, which btw also occurred when I-5 was built) with long, smooth curves both vertical and horizontal that allow a train to run at 180 or more (225-250 to meet original HSR proposition specs). Every bridge and interchange would need to be replaced. So Cox is dreaming; a HSR line along I-5 (which would work well for flyover traffic only, therefore even a bigger boondoggle what what we're getting now) would hardly be a piece of cake or cheap to build; the only thing you would avoid would be going through or around the towns along 99 that the current alignment has to deal with.

A hyperloop along I-5 would have the same problem, but worse due to the higher (potential) speed.

Would Cox prefer something along 101? Hee Hee watch the volcanic eruption in Santa Barbara... But of course in common with most of the Republicans he'd prefer nothing.