An eight-mile section of the London orbital road between junction 23 and 25 will be the first motorway in the country to use the hard-shoulder as a full-time live traffic lane, as well as utilising new camera technology to improve traffic management.
Infrared CCTV has been installed on the stretch by the Highways Agency to allow staff at its control centres to have greater visibility of the road network and respond to incidents as they develop.
The agency claims that the new technology will improve journey reliability by reducing congestion and easing traffic flow.
Graham Dalton, Highways Agency chief executive said: "The design changes have meant that smart motorways are quicker to build, more intuitive for drivers and more efficient to operate, while maintaining safety," reports the Hertfordshire Mercury.
The new smart motorway, which has seen 1.1 million man hours go into its completion, will also see new gantries and overhead signals, as well as refuge areas in place of the hard shoulder.
A further section of the M25, between junction 25 and 27, is also undergoing similar improvements, which are scheduled for completion towards the end of this year.
Sections of smart motorway are also planned for sections of the M1, M3 and M62.
Roads minister Robert Goodwill said: "The additional capacity on the M25 is part of the government's record investment in the strategic road network, with £15.1bn being invested to add over 400 lane miles of capacity on our busiest motorways by 2021.
"Our motorways are the backbone of Britain and vital to building the UK economy, with approximately four million vehicles using them each day."