con ‧ tra ‧ flow /ˈkɒntrəfləʊ $ ˈkɑːntrəfloʊ/ BrE AmE noun [uncountable and countable] British English
a temporary arrangement on a road that is being repaired, that makes traffic travelling in both directions use only one side of the road:
A contraflow is in operation between Junctions 6 and 12.