I don't think this will change much, they've been using lane restrictions via signs for ages...
Plan for 'smart' junctions to end gridlock on M25 | Transport | News | London Evening Standard
the problem is bottle necks. For some of you that do not know the M25 circling Englands capital London. There are areas of the motor way still only 3 lanes & other areas as wide as 10 lane.
Like with any motorway, there's a huge amount of traffic on one road, heading the same way & when one lane is blocked, the tail back begins.
Would not extending 2 extra lanes work, by keeping one of the new lanes permanently closed, only opening if there was an accident or other obvious emergencies.