This is odd.

When the French take vacations, they nearly always take them in late July and August, and they overwhelmingly take them in their own country.

Which means those of us in the south of the country, where the dependable sun is, can expect a major influx of visitors from the north choking the major roads.

But it comes with a twist.

Much of the mass migration comes on the same handful of days. Which just seems silly.

One of those days is on Saturday, the first Saturday after the conclusion of the school year.

Already, we are bracing for the flood of tourists in their trailers and SUVs, moving en masse toward the beaches of the Mediterranean, where entire blocks of summer-only apartments are jammed during the second half of summer — and sit empty most of the rest of the year.

It will be a miserable traffic weekend“, according to the English-language Languedoc Living site, crediting “traffic info service Bison Fute”.

Motorists have been advised to “avoid traveling from 3 p.m. Friday afternoon and the whole of Saturday”, when tens of thousands of holidaymakers will head out of cities towards the coast or countryside.

Typically, in this part of the country, traffic is bearable, verging on “light”. It is not an every-day-of-the-week nightmare as it is in, say, Los Angeles.

But then come these ugly days, and people continue to drive as if the roads are clear, rather than crowded, and a wreck here or there bogs down the whole of the system.

Perhaps the biggest traffic day of the year, in France, is the last Saturday in July. That is when the July vacationers pack up and head home and are replaced in their beach apartments by the August vacationers. That is, masses of people are moving both south and north.

(Must be like Black Friday, at the rest stops along the major motorways.)

This year, that blighted day is July 29, and I am making a mental note to avoid driving on any of the major highways. Just hunker down in the house or take a walk around the town, wait till the tail end of the lemming procession has passed by us.

What is curious is the mass behavior by the French. It strikes me as a European thing, too — everyone doing their vacations the same way because it’s how they have always done it. Preferably in August. Several weeks. The whole of the family.

Why not leave a day early, motor within a few miles of your destination, and stay in a hotel for a night?

How about leaving a day later, after most everyone else is off the highway? And just accept that your vacation rental will be used for 27 nights instead of 28? Or returning a day ahead of everyone else and get home before the madness begins? (Significant numbers of Yanks would use one of those options.)

Isn’t that easier to deal with than the nose-to-tail stress of driving from, say, Paris or some other soggy northern city — or even Belgium or The Netherlands? And back?

It is a conformist society, it would seem. At least when it comes to vacations. Even if it means some ridiculously high fraction of travelers head out on the same days and suffer the consequences.

Bison Fute has classed traffic across the whole of France on Saturday as “red” – the second-highest level before black – meaning traveling on roads from all major French cities will be “very difficult” with the possibility of jammed roads from 7 a.m. to 7 p.m.

The July 29 outlook? It will be a “black” day, the worst rating.

Bison Fute’s “ideal travel time” for the following Saturday?

Do it on Sunday.

Not that the French or their fellow Euros will consider that.