(a) The highway described in Schedule 1 to this Order and shown by striped hatching on the deposited plan; and
(b) The new highways which the Secretary of State proposes to construct along the routes described in Schedule 2 to this Order which connect the existing highway to become a trunk road with other highways at the place stated in that Schedule (the highways along these routes being in this Order referred to as ``the slip roads'')
shall become trunk roads as from the date when the new trunk roads are open to through traffic.