[narwan]

Marcello said:
Ok, let's see if I get this.You are proposing to create obstacles on the roads and in order to prevent said obstacles to be easily bypassed you are proposing digging trenches

Nope. Never said the obstacles would be easily bypassable. On the contrary, if they were they wouldn't exactly match the definition of an obstacle now would they? The whole trenches thing which you seem to get hung up on was nothing more than a simple side remark as part of a list of possible ways to create blockades. Which means it was only one of many options and that clearly implies that in mnay situations there would be other and better alternatives. But in some it could be of great use. My reference to blocking trucks is simply to reitterate that we're talking about blocking supply units, NOT combat units.

Marcello said:
Now, it seems pretty evident to me that this requires a a trench long, deep and wide enough that either going off road and driving around it or filling it to create a passage would be a significant nuisance and time wasting, thus creating a bottleneck. A ten meters long trench simply will not do the trick.

Well, you clearly imagine a piece of terrain where 10 meters wouldn't do the trick. What's important though are those few places were 10 metres (or 20 etc depeding on what is effectively feasible in a situation) would do the trick! The whole point of the 'art of obstruction' is to do it where it counts.

Marcello said:
"It is much, much easier to demolish and block than it is to clear and circumvent."

It depends exactly on what sort of blocks are being talked about.

Exactly. The right type of block for the right type of place. Glad you agree.

Marcello said:
The israelis spent a couple of years building the
Bar-Lev line. The egyptians breached it in matter of hours.

A defensive line is something completely different, as is breaking a line in combat. You will also know then that after the breakthrough the egyptians had a very hard time keeping the troops on the other side supplied.

Narwan