[rz2k]

They very rarely need to plow snow in New York city, but when they do there are hundreds of miles to plow, and it is much faster if they begin the plowing before even an inch accumulates.

It is much more efficient to press the thousands garbage trucks into this rapid snow plowing service a few days per year than to waste 20 acres storing snow plows for the 350 days per year when they are not needed.

[mertd]

They also bury the trash bags under the plowed snow, which is a win-win for them because they can forget about collecting them until spring. :)

[i_am_proteus]

This and also: NYC residential trash collection is curbside. Literally leave trash bags on the curb. Trash collection cannot occur when the curb is snowed in.

So, were there separate trucks for the two tasks, the trash trucks would sit idle until after the snow plow trucks had finished their rounds.

Given the infrequency and relatively small volume of snow NYC gets, plus the curbside trash collection, sharing trucks and drivers is reasonably efficient.