Not the previous poster, but it seems "black" represents garbage truck whilst "green" represents recycling.
The argument they were making is if your garbage weren't going to a recycling plant, it would be going to a landfill. Either way, the same amount of waste has to be transported from your home, so the same number of trucks would still be driving around.
Recycling is a trivial number of trucks. And far as I know, they don't crush the material. Also they keep it separate (paper/glass/metal) and the sections probably never fill evenly. So a pretty inefficient operation is my guess.
That may be with the recycling operation were you live, but everywhere I have lived it's been one bin type, one truck, dump the bin and go. The only time I have had to do more than separate paper from non-paper was back when I also had to hand-carry recyclables to a drop spot.
But then your garbage truck (black) would have to pick up all the recycling that the green truck used to pick up.
So unless your current black trucks are never full then you would either need more black trucks or they would need to make 2x the trips.
Not sure what black/green means. We have separate recycling pickup vehicles around here. They wouldn't run at all if there were no recycling.