A songthau is a van type thing, that acts as a kind of bus. Here is one:
Today we were on one with 21 people (there are seats for 8). We were all sitting on each others knees and at every stop more people would get on. People were hanging off the back as we drove down the Asia highway. It was about a million degrees. At one stop a woman climbed on board with what looked like a towel. It was a brand new baby (born earlier today) wrapped in toweling. It's mother followed, left hanging off the end of the songthau having only just given birth. Not a word of complaint. Incredible.