On a motorway, where would vehicles travelling in opposite directions share the same carriageway?

Explanation: Contraflow systems allow traffic to pass in opposite directions on the same carriageway; they're usually found where roadworks are being carried out. Care is needed as the lanes may be narrower than normal, the road surface may be poor, and oncoming traffic will be passing much closer than normal.

Category: Band 2 traffic signs and signals

References: The Official DVSA Guide to Driving: Section 11, Highway Code: Rule 290, Know Your Traffic Signs: Page 130