In Laos the Tuk-tuks are made by merging the front end of a bike with a trailer backend. The driver "rides" the bike and the passengers sit in the back. There are three classes of tuk-tuk: small "bok-boks" like this, with room for four passengers, medium sized tuk-tuks, with room for six, and "jumbos", which also carry six, but have been fitted with car tyres for travelling on bad roads.
When the driver hasn't got any work, he's able to string a hammock from the canopy and roll down the sides, so that he can have a quick nap.
More about our Vientiane visit at newdigate.me/2010/03/vientiane-capital-of-laos/