The move from 4 inch to 6 inch wide stripes has absolutely nothing to do with drivers seeing the stripes better or them lasting longer.
All this money is being spent so the few self-driving cars on the road don’t crash. Self-driving cars have massive difficulty seeing 4 inch wide stripes. They needs stripes a minimum of 6 inches wide to stay safely in their lane. So California state freeways and highways are being re-striped from Canada to Mexico at high cost so that a tiny handful of automated self-driving cars don’t crash.
While the 6 inch wide stripes will eventually be needed as more self-driving cars appear on roads, there was no need for a massive restriping of the entire state. This could have been done piecemeal as each section of road was being worked on.
And it is a lie that 6 inch wide stripes last longer than 4 inch wide stripes. Semi truck tires will wear them down equally fast.
Which makes me wonder, will highway departments have to return to the southern/western style triple-stripe centerlines for head-to-head traffic to stop automated vehicles from crashing?