crab shuffle

occasionally see this & wonder just how it works: following a bloatmobile down the freeway. it's a long straight stretch of road. i'm relaxed in my chair, more or less centred at the wheel & i can easily see the driver's front wheel of the bloatmobile. how can that be? is the idiot (an old fart, turns out) driving it weird? or is its alignment off—that drastically?