By Jove, it does work on everything!
]]>Nearly all of the area of a road is really there because human drivers do stupid human stuff. Shoulders, extra space in the lanes, the pavement in the center of each lanes...
If you assume self-driving vehicles when you're roadbuilding, your road goes from one ten-foot-wide swath of asphalt for each lane to two one-foot-wide swaths. You put in occasional "ramps" for lane changes, with markers so that the auto-driver knows when it's allowed to do that. Cost of roadbuilding goes down by probably three-quarters, and it takes much less time to lay the pavement down. If you can build self-driving motorcycles, you get footpath-sized roads not unlike the ones the Chinese used for millenia. (www.lowtechmagazine.com/2011/12/the-chinese-wheelbarrow.html‎ has a reasonably good description.)
Since we're talking "geopolitical," look at the military applications. You can build a narrow-gauge tracked vehicle that will build an entire temporary paved road, moving at walking speed, and not using all that much material. (Lotta rammed earth going on here, or maybe dirt with binders added.) Suddenly, new supply lines grow themselves, at a rate of maybe fifty miles per day. You end up with supply deltas; no huge depots, no ammo dumps, just a widely distributed mesh of tiny roadlets with tiny beetly carty things carrying all the stuff.
]]>Sentence from 2053:
The Rough Tunnel rain might just keep us going, if we can build enough rosmem to clear it.
Which is part tech : "rosmem" = reverse osmosis membrane, add power and it converts brackish/salt/contaminated water to pure. It's a substance because you just stretch it across a frame of some kind; and part event: the Rough Tunnel is the valley that the Indians dig through the Himalayan Plateau when their country gets uninhabitable. Since they use fusion demo charges for a lot of it, you get lots of dust in the high atmosphere, which buys the world a couple of years of cooling but means you've got to filter your irrigation water if you want to eat your crops. Biofuels are a fallback, but people don't pay as much for a BTU of radioactive diesel as for two BTUs of edible wheat.
Might be a 2043 sentence, but I think 2033 is a little early.
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