Actually, these more thorough posts were intended earlier than the discussion on the Suspension-system in November, and they were thought as an introduction to the carved material found in the northern roman provinces and in Rome herself.
In Rome some of the most prominent buildings show wagons in more scenes, e.g. The Column of Marcus Aurelius on the Piazza Colonna, and the Arch of Septimius Severus (photo right) in the Forum Romanum, but 
wagons are also represented on sarcophagi, in both mythical and “every-day-life”-scenes.
These are all nice carvings contributing in different contexts, but my personal field of interest is on the carvings from the northern roman provinces, especially from Pannonia (around modern Hungary) and Gallia Belgica (around Germany and Belgium). Most of these stem from 
burial monuments of some kind, but we do not know that 
many details about most of the monuments. In Arlon, Belgium, a lot of carvings were found build into a fortifying wall from the end of the third century AD, without any traces of origin or inscription to let us know more about the story of the carvings.
In the roman province of Pannonia, according to the National museum in Budapest, there was a “pre-roman” tradition saying, that dead people was transported into death on a wagon, which is why many tombstones/stelai show a carved wagon along with the grave inscription. Often the type of wagon used is the four-wheeled transport-wagon, as seen on the photo left, but in a few cases, where supposedly dealing with more wealthy persons, the two-wheeled wagon-type, as seen on the photo right, is used. This latter wagon-type is also seen on some city-roman sarcophagi, in a bit different output, though. Here the type is called “Sessel-wagen” in German, but I have not been able to find neither the English nor Latin word for the wagon-type yet. The Latin name would be crucial, though, if one were to make a full typology of the roman wagon types.
