Re: How can this "micro trenching" possibly work?
Around here I love it when i see them resurfacing a road with asphalt instead of redoing the concrete. If they redo the concrete it will be closed all year, and sometimes take longer than that. Asphalt may need to be done more often, but it is very quick - if they aren't messing around taking advantage of the closure for other maintenance it they can do a mile long section in a week, easy.
From what I can tell they will do a road in concrete, then they'll redo it with asphalt several times, but I guess at some point the concrete underneath gets in bad enough shape that they have to rip everything out and start the whole process all over again.
I love riding my bike on newly done asphalt - it is so smooth. Concrete never is as smooth due to the expansion joints, and the texture they 'comb' into it. Of course 10 years down the road, the asphalt is a minefield of patchwork that has me praying for it to get resurfaced ASAP, while 10 year old concrete is still in pretty good shape...