Along the lines of the past-to-present historical tactical analysis that the discussion has moved toward....picked up an old (1962) copy of General Grivas on Guerrilla Warfare recently. Grivas was the leader of the EOKA on Cyprus from '54 to '59 who fought a campaign that blended classic guerrilla warfare with terrorism against the Brits and the Turkish Cypriots.

He describes in detail the use of roadside/in-road RCIEDs (he refers to them more simply as mines) in his campaign.
...on tarred roads we used what we called a "small cannon", a tube of any size, closed at one end and filled with explosives or gunpowder mixed with fragments of iron which acted as projectiles. This contraption was made fast to a tree or wall by the side of the road at a suitable height or angle, so that when it was electrically detonated the projectile should strike the target. The "small cannon", when used by our groups, yielded excellent results and very rarely failed to come off. After our mines were perfected and more powerful, the results obtained were remarkable, vehicles being hurled a distance of as much as 16 to 22 yards, and hardly any of the occupants came off unharmed...
So, here we have an excellent example from the 1950s of insurgents making use of IEDs, what sounds like crude versions of EFPs, and their continuing creative evolution of the techniques in combat.

Overall it was an excellent book, that I highly recommend to the group. I finished it with a strong interest to learn if our British partners have any contemporary resource material studying the IED ("mine") TTPs of EOKA...