Traffic circle

Why do the cars go around a flat circle in the road? This vehicle can be clearly seen to have just gone around the traffic circle because the front tyres are still in the cornering mode. Vehicles will go to great lengths to miss crossing the circle even with their back tyres, this also includes large trucks. Trucks will approach very close to the pavement in order to 'go around' the white, very slightly raised circle, even when there are no other vehicles anywhere in sight. This could have been a reaction to having someone crouched, taking a photograph, as the vehicles went by, but this is an unlikely scenario. It is more likely that the larger roundabouts that exist elsewhere, have conditioned motorists to go around the item above; although this would not apply to people that have never driven anywhere but on the Orkney Mainland, so it can only be assumed that it is considered bad manners, or bad driving, if a driver in fact does refuse to go around the circle and instead decides to drive straight over it. This is a point of authoritarian control, where the rules of the Highway Code are adhered to by all motorists; the code is adhered to even when no other traffic is present, much in the same way as using an indicator when there is no other person/vehicle around to inform of a driver's intended action. The rules are so deeply ingrained in to the subconscious of the road user, that they are followed automatically and without necessary forethought.