Commuting

[Dead Eye]

I agree with what you say about the M25 traffic - I tend to lane swap to get around the crazy people who stick in lanes 3 and 4 doing 65mph...

In all but the heaviest of traffic I tend to find lane 2 and 3 the quietest, with lane 1 being occupied by trucks and lane 4 with everyone who wants to go fast, but whom aren't really getting anywhere

For filtering, I would reference it as passing between two vehicles who are literally side-by-side - otherwise it's an overtake / undertake as you say