I'm just that good! I know good people. Very good people.

@nic, I travel too much to do all the flagging and reviews! Those frequent flier miles won't earn themselves!

@JonCuster, I am not advocating for doing 15+ below the limit; my max under is at most 15mph under; e.g., I'd probably go 60mph if the limit is 75mph (which is the max on this PHX-ABQ-AUS route), and hardly any roads have limits above 75mph in US (I may as well go 65mph if it's 80mph and road ain't empty). BTW, I realised that going 50—60mph not only lets you conserve the fuel considerably, but also lets you enjoy the scenery without as much of a risk of a split second getting you off-road.

@JimMacKenzie, yes, of course; coming from someone who used to drive 80+, I'm obviously going to take reasonable care to ensure not to intentionally (or by omission) obstruct my prior selves. :-) Plus, even though the roads are designed for 80+, they're still usually posted at just 70mph or 75, which I'll likely cruise at 15 under, in the left lane.

@VMAtm, I don't really understand what your comment is about, or why someone downvoted this answer recently; the law is pretty clear that passport must be issued within 3 mo, has nothing to do with gathering the documents.

@Tom, your statement is not true; I haven't seen a single station in Lubbock to have 87, for example.

@NateEldredge, in West Texas around Lubbock, was offered 86, 88 and 91 at United Express. No 87. Are you sure California still has 87 even in Truckee?

@NateEldredge, that's basically an empty table! I think I recall seeing some such table, but it was likewise half-empty, plus the values didn't seem to be correct to start with. Realistically, the map would be unlikely to be divided with state lines, as many states, from Texas to Colorado, have quite varying levels of elevation.

@ZachLipton, yes, exactly -- the numbers are always displayed once you're at the pump, but GasBuddy isn't regulated. :-)