We had regular & diesel both at $1.79 here last week, which means they were both $1.5x [or cheaper] just east & west of us in southern Missouri.
Diesel was cheaper than regular when we bought our Duramax a few years ago, so we thought we'd be ahead of the game, then within 6 months it jumped up to over .50 more and has been at least that much higher ever since...with it now on par with regular, it makes me wanna get it out of the shop and start putting miles on it again!