There must be a reason someone feels it is worth moving all these lampposts. I'm just guessing that the nearer a lamppost is to the road, the more likely it is going to be flattened by a rogue car, or bumped by someone parking.
They are moving the lamposts to the rear of the pavement so that they light the pavement as well as the road (supposedly). The new design are more directional and so less light washes the surrounding area or goes up to the sky. This is done deliberately to reduce 'light pollution'.