Why?

An enduring mystery for me about Cambodia is one of their driving quirks: drivers of three- and four-wheel vehicles don’t drive in the middle of the lane as might be expected. Instead it is normal for the driver to straddle the lane marker–not to center the car or tuk-tuk on the white line but rather to make sure one wheel is over the line. In this photo of a three-wheel tuk-tuk on a definitely not-crowded street, the right wheel straddles the lane marker. Why do they do that?