The first is a smallish 4 cubic yard dumpster, actual dimensions being approximately 72"x48"x65".
Before starting construction, I questioned what scale they should be constructed in. I've generally accepted that 28mm is about 1/56th, but I decided to use 1/43 scale vehicles for these games. Most of the cars are actually smaller than 1/43, and most of the trucks are actually 1/50th or smaller, so the distortion isn't as bad as it might seem initially. I also figured that I might well use some 1/48th scale accessories from model railroading, model ship-building, etc.
So back to the dumpsters, my concern was that a 1/56th scale dumpster would look too small next to 1/43 to 1/50 scale cars and trucks. I also wanted figures to fit in at least some of the dumpsters, which would be harder to do in 1/56 scale. On the flip side, at 1/48 scale, the compromise scale I decided that I would use if the vehicles looked to big for 1/56, I was afraid that they would tower over the figs and even smaller buildings.
I ended up sketching out three views of each of five different sized dumpsters in both 1/56 and 1/48. I still had the same concerns. Big dumpsters looked too big in 1/48, and small ones looked too small in 1/56. I still couldn't get a good feeling for how they would look with other accessories such as fire hydrants, garbage cans, mail boxes, etc.
In the end I decided to just start building and see what looked okay. The smallest of the dumpsters that I had scaled was the 4 yard one mentioned above. I decided to build it in 1/56 and see how it looked. If it appeared too small next to the figs and cars, I'd junk it, and go with 1/48. If it looked okay, I'd just do them all in 1/48 scale.
So here is the result.