I used to drive 18 wheelers, there is no provision to even get up there to "clean off the mess." Even at that, my mortal fear of heights would have kept me off of the slippery roof of the trailer.

The only drivers that don't have time to take care of themselves, aren't managing their time very well. With a few exceptions, I've never been in a true rush to get to a scheduled delivery destination on time. Most of the "constantly late driver's I've come across were typically truck stop cowboys, or spent too much time fooling around during offtime, making it necessary to be "off duty" longer than would have been normally necessary.