This is an emotional time for my wife and me, as our youngest kid just got his learner's permit and it's dawning on us that this is the last time we'll experience the stomach-churning stress that comes with having a rookie driver in the family.
As I did with the two older kids, I have tried to impart to the boy my philosophy on driving, which is that everyone on the road is insane and you can never let your guard down, because they're all trying to kill you.
My wife thinks this tends to make the kids jittery behind the wheel.
"Why can't you just tell them to 'drive defensively' and leave it at that?" she said.
"They have to know about the lunatics," I told her. "Not telling them would be like not telling a toddler that some dogs bite."
So a few weeks ago, the boy and I drove to the Essex branch of the MVA, that grim, fluorescent-lit outpost where bored-looking civil servants process driver services forms for sullen citizens, and he got his learner's permit.
It turns out he's a very good driver, although in keeping with parental law, I am nevertheless required to say "Slow down, slow down" every five seconds when he's behind the wheel.
But this is more than my wife says, since when she drives with the boy, she sits there mute in the front passenger seat with a look of bug-eyed terror, gasping and reaching for the dashboard every time he slows down or makes a turn.
The boy says she makes him nervous.
But she does the same thing when I drive, which makes me nervous, too.
So it's something he's going to have to live with.
Another thing we've noticed is that the boy seems reluctant to keep his hands at the 9 o'clock and 3 o'clock positions on the steering wheel, as recommended by driver-training experts.
Part of this has to do with the fact that young people have no idea what the 9 o'clock and 3 o'clock positions are, since they don't look at clocks anymore and all their watches are digital.
But the other part has to do with the fact that holding the steering wheel in the 9 o'clock and 3 o'clock positions doesn't look cool, and they're afraid other young people will think they're dorks if they drive in this manner.
So the boy keeps trying to drive with one hand, and my wife and I keep telling him this is against the law, although he knows from his brief driving career that it's absolutely fine to drive in this state while you're yakking on a cell phone or eating a slice of pizza or combing your hair in the rear-view mirror.
The other day, the boy drove for the first time on the Beltway, that traffic-choked ribbon of macadam that encircles Baltimore and offers a more, um, challenging driving environment.
Almost immediately, he was treated to the full panorama of mental illness that's on display there 24 hours a day.
First he had a guy in an Audi doing 85 mph roar up behind him in the right lane, then shoot past and weave in and out of traffic as startled motorists hit their brakes and tried to get out of his way.
Then we got behind a woman wearing a scarf and driving a Honda Civic doing 40 mph, causing a long line of slow-moving cars to form behind her. At first glance, you might have thought it was a funeral procession.
Naturally, the woman in the Civic seemed oblivious to the problems she was causing, even as one car after another managed to pass her, and the drivers shot her dirty looks.
Seeing the woman wearing the scarf poke along reminded me of the Little-Old-Guy-With-The-Hat Theory, first espoused in this space years ago.
This is the theory that says if you ever find yourself behind a car driven by a little old guy with a hat, you can automatically figure on your trip taking longer.
Because he'll drive at least 20 mph below the speed limit.
If the little old guy is wearing a baseball cap, then your delay might not be too bad - figure 5 or 10 minutes.
If he's wearing a Greek fisherman's cap, it'll probably be a little longer, maybe 15 or 20 minutes.
And if he's wearing an old-fashioned fedora, forget it, you're doomed.
The guy will be poking along so slowly you'll think he's driving in reverse.
Figure on a half-hour to an hour delay, easy.
But I didn't get into the Little-Old-Guy-With-The-Hat Theory with the boy as we drove the Beltway.
There will be plenty of time for that in the weeks and months ahead.
Getting behind the woman in the scarf was enough for one day.