How much cost the Motorway widening every Year?
It must be cost effective otherwise they wouldn’t do it 
Does this thing keep you awake at night ?
dar1976:
It must be cost effective otherwise they wouldn’t do it
The alternative, more cynical answer is: “It must buy enough votes otherwise they wouldn’t do it ”
There’s some parts of the m25 they could do with widening to 5 or 6 lanes rather than from 3 to 4.
if people didn’t hog the overtaking lanes, then we wouldn’t need all this widening work.
Silver_Surfer:
There’s some parts of the m25 they could do with widening to 5 or 6 lanes rather than from 3 to 4.
This would not help with congestion. Congestion happens at junctions where Mr Rep in his Vectra swings from the outside lane to the inside lane at the last moment cutting everyone up. Just look at the 5 lane section of the M25/M3 junction southbound if you need convincing. Terrible even out of rush hour because there are too many lanes with too many people trying to change lane.