Passing lane
A passing lane (North American English), overtaking lane (English outside North America) is a lane on a multi-lane highway or motorway closest to the median of the road (the central reservation) used for passing vehicles in other lanes. (North American usage also calls the higher-speed lane nearest the median the "inside lane" but in the United Kingdom this is the "outside lane".) Countries with right-hand traffic put the passing lane on the left; those with left-hand traffic put the passing lane on the right.