Marshrutkas are just privately operated buses with fixed routes ("marshrut" = "route" in Russian, marshrutka is short for "marshrutnoe taxi" = "fixed route taxi

Marshrutkas are just privately operated buses with fixed routes ("marshrut" = "route" in Russian, marshrutka is short for "marshrutnoe taxi" = "fixed route taxi"). They used to be loosely regulated, which resulted in various safety concerns, as the vehicles they drove were barely street legal. They're pretty much phased out right now, and replaced with regular buses.