We have shared bus/bike lanes now, but what about shared bus/truck lanes?

I was in Germany in September where this is the standard at the overwhelming majority of traffic lights. I did see several exclusive non-concurrent phases (always automatic) in Berlin, and in the greater Berlin area, I saw a total of four beg buttons, two of which were at temporary traffic signals in construction zones, a permanent one on Unter den Linden and another permanent one outside of Potsdam's central train station. The two permanent beg button lights were at midblock/non-intersection crossings. I saw no beg buttons in Munich. I asked my German friend who lives in Berlin about them and he told me that the walk signal will eventually come on, that the beg buttons just shorten the wait time or, in some cases, prolong the walk signal for slow crossers, not to mention, some "invisible" crosswalks, only marked by a lowered curb (mostly on "playing streets", where drivers are warned by signage that they may drive there, but need to keep it at or below 10km/h and must yield to all vulnerable road traffic). Germans generally don't walk against the light, partially because they're universally predictable (none of this concurrent automatic in one direction, beg button in the other direction nonsense that's too common in Boston (see Berkeley St in the South End), or hodgepodge of settings from one intersection to the other that are the result of Boston's (or really the US's) lack of standards) and the waits are rarely very long, though I saw a lot of midblock crossing in Berlin and Munich. Another advantage to near-universal concurrent walk signals is that it does not give a legal right of way to a turning car over pedestrians going straight who get a don't walk, as is too common here, and drivers turning will be conditioned to expect to yield at almost all turns.