This would reduce congestion on a lot of motorways and unclog the "arteries" of the country. This may also stop roads being snowed up during winter months if they were used 24/7. It would reduce accidents; pollution; road rage; fuel consumption; journey time and many other incidental problems associated with our roads. It would also free-up the hard shoulders that are currently being used as roads and give us back our safety margin on those motorways. Heavy goods driving will have to become nocturnal but many people work shifts all their lives and many HGV drivers already work nights.
Let's use the roads 24/7 not just during "working" hours.