A6144(M) motorway ceased being a special road on 25 May 2006 losing its motorway status. It is now subject to a 50 mph (80 km/h) speed limit and is classified as the A6144. The road through Sale retained the A6144 number, meaning that there are two branches (and two junctions with the M60 motorway) with the same road number. Despite losing motorway status, the road still prohibits pedestrians, cyclists, and horse riders. Following the change of signage on 25 May 2006, two marker posts, the A6144(M) confirmation sign and a lay-by warning sign are privately preserved. A6144(M) motorway The A6144(M) was a
Dartford Crossing to be part of a general orbital route around London and was provisionally known as part of the "South Orbital Road". The first engineering work to take place was a compressed air driven pilot tunnel, which was drilled between 1936 and 1938. Work on the tunnel was delayed due to World War II, and resumed in 1959, using a Greathead Shield, similar to the work on the Blackwall Tunnel some 60 years earlier. The delay in work due to the war allowed the tunnel's design to be improved, which included a better ventilation system. After negotiations with the Ministry of