Moon dust

One of the particular annoyances of the Moon is the dust.

Unlike of terrestrial dust where the particles get eroded into civilized shapes, moon dust is all sharp-edged and jagged. And hard, like glass. Sticks to the surfaces (the astronauts on the Moon had dirty spacesuits all the time), sticks to everything sticky (the moon buggy repair with duct tape was problematic at first exactly because this), gets electrically charged and some of the particles then hover above the surface. And when carried into an area with air, smells like burnt gunpowder.
http://www.spacedaily.com/news/lunar-05o.html
http://www.physorg.com/news10518.html
http://www.wired.com/science/space/news/2005/04/67110
http://science.nasa.gov/headlines/y2008/21apr_ducttape.htm (note the photo of a dust-smudged astronaut back in the lander)
http://www.hq.nasa.gov/alsj/alsj-dustbrush.html (a nice dialogue describing the lander cabin, full of dust, as a neat and orderly coal mine)

When it gets into bearings, it acts like a fairly efficient abrasive, causing wear. It also can damage seals. Surfaces of optical systems suffer especially much.

Its behavior when disturbed is also different than on Earth. There is lower gravity, so the particles travel further when kicked up, and there is no gaseous medium so there is no turbulence. Even when disturbed with jets of gas from engines, the gas does not cause noticeable turbulences as it expands too fast.

Keeping dust removed from roads, to prevent the dust clouds behind vehicles shown in the trailer, therefore sounds like a good idea for prudent Germans. Offroad routes are a different thing, however.