I would take a wild guess at 1920s rather than before the First World War, just something about the scene. Are the two vehicles connected? People are standing in front of the, presumably stationary, hearse-like one to get a look at the front one drive by and the "hearse" is facing in the opposite direction to the front car. I would guess the front one is a visit by an "important" person, probably not Royalty as the police would salute them as well. Might the cap touchers be ex-servicemen saluting someone senior military? I don't think the crowd would behave like that, hanging out of tram windows etc, for a funeral.
Robert