When the holidays begin, my reptilian brain takes over. It keeps me breathing, but as McGill University describes it, “The reptilian brain … tends to be somewhat rigid and compulsive.”

That’s attractive. Or not, especially when it comes to car travel this time of year.

I’m turning to a couple of sources for attitude adjustment. The first is from a new book by Scott and Alison Stratten called “The Jackass Whisperer.” It is a compendium of examples of bad behavior, aka jackassery, each followed by notes about the 3-year-old’s (unfiltered and sometimes unhinged) way to respond and the whisperer’s, or adult, way to respond to these affronts to decent conduct.

Not surprisingly, a large chapter describes “The Jackass in Transit,” which notes that “travel brings out the colicky baby in all of us.” The Jackass “doesn’t think the speed limit applies to them.” They also talk on the phone, follow your vehicle too closely, don’t let anyone into their lane and never turn off their turn signal.

As a driver, you would never do these things, at least, not on purpose. But what if you did by mistake? And what if those people who are riding with you took every opportunity to point out every flaw in your road technique?

Welcome to Adulting, Part 2, where coexisting in a car is more than just a test of wills; it’s a test of how well you receive and respond to feedback from a BSD — back-seat driver.

A 2019 survey by Ford suggested the answer to that is “Not terribly well.” About 10% of respondents have ended a relationship because of back-seat driving, it said.

About half of all drivers “don’t listen to back-seat drivers, but 20% blame them for road rage,” said Jess Carbino, whose doctorate in sociology from the University of California, Los Angeles, has led her to become a relationship expert, including stints as a sociologist for Tinder and Bumble dating apps.

The helpful advice that the BSD is trying to impart not only upsets the driver but, according to the survey, also is the source of more than half the arguments in the car, Carbino said.

If you’re the BSD, you may think you’re saving lives by screaming, “Watch out for that car!” Could be, but it also could be that you’re damaging a relationship by delivering that information in a way that could be labeled jackassery. A better way, Carbino said, might be something like, “From where I’m sitting, you might be a little too close to that car.”

Even if that’s delivered in a cool and calm voice, I’d still be tempted to tell the BSD where to go, and it wouldn’t be to the destination for which we were originally headed.

The solution, Carbino said, is to talk before you make the trip. Discuss what’s appropriate and set boundaries. If kids are on the trip, include them in the conversation. Everybody should understand what their role is and is not, and that failure to be respectful “can lead to feelings of resentment,” Carbino said.

If you’re giving “helpful” advice, note that it might not be perceived as such. “Individuals who are trying to be helpful in giving advice actually have the opposite effect,” she said.

Can this car trip/relationship/family be saved?

Hope and help are at hand, Carbino said, thanks also to technology, much of it available in newer cars. People believe in its safety value, the Ford study said. Consider that:

>> Some cars can parallel park, which makes “you stink at this” a thing of the past.

>> Cruise control can help you keep to a (provable) and steady speed. Adaptive cruise control will slow your vehicle if it’s coming up too quickly on the car ahead.

>> Backup cameras can help you see seemingly around corners (cars that are coming) and, of course, behind you.

>> Blind-spot mirror sensors may help ensure you’re not cutting it too close when you change lanes.

>> Front-bumper sensors also help when you’re in tight quarters, alerting you to cars that are too close for comfort.

You need not buy a new car; some of these are available as after-market items.

Technology will never replace acting like an adult, but it’s a good companion for a less nettlesome ride. And please don’t clip this column and hand it to the offender. It’s no substitute for discussion. But as the impetus for conversations? I’m all for happier holidays every time.