I've been wondering the same, If your going 70+mph through Needles you'll get moved over a little bit on one of the turns, this is where it makes sense to slow to 60mph, but when you get to Ludlow, you have 25+ miles of brand spankin new HWY posted 60mph. There's one 60mph sign right after the west bound rest area that said END 60mph for the longest time, until somebody scratched it out "END". I used to jump right back up to 75-78 after seeing that, then see a 60mph sign posted by the Military Base im like WTF.