Definition of slip road

The term "slip road" originally came into use in the mid-20th century, as part of the development of modern motorway systems. In England, the first motorway to be constructed was the Preston bypass (M6), which opened in 1958. A "slip road" or "slip lane" refers to a short connecting road that links a main motorway with either an adjacent junction or another section of the same motorway, typically at different speeds or orientations. These slip roads are designed to provide safe and efficient entry and exit points for motorists, helping to minimize the impact of these movements on the main carriageway of the motorway. The roots of the term itself go back to the railway industry, where a "slip line" was a short, connecting track for vehicles to move between different railway lines or platforms. This usage can be traced back to the late 19th century, as a means of facilitating the movement of rolling stock and passengers between different railway lines. By the mid-20th century, as automobile traffic began to increase and motorways were being constructed, the term "slip road" came into use in the context of motorways and highways. The name reflects the similarity between these short connecting roads and the railway industry's "slip lines," as they both facilitate the movement of vehicles between different transportation systems or modes. Overall, the use of slip roads has become a standard feature of modern motorway and highway designs, allowing for safe and efficient movements of vehicles onto and off of these major transportation networks.