If this hasn’t happened to you, you must be taking the train or the bus to work.

A bit of discourteous driving, a honk on the horn in complaint, and the next thing you know, some raving my-life’s-not-my-fault rageaholic is screaming, gesturing, stopping short or trying to provoke some accident or reaction that will allow him to give full vent to the fury that is his beef with the big, wide world.

“Unhinged” taps into that, makes its home there. And thanks to the fact that this film by a start-up studio will be the first American movie to open wide in mid COVID 19 pandemic, it’s the best showcase Russell Crowe‘s had in forever.

Sure, it’s a B-picture, a straight-up rage-on-the-road genre movie in the “Duel,””Changing Lanes” or “Falling Down” mold. But Crowe, overweight and the very embodiment of “gone to seed,” gives this villain-we-all-know a face to fear and a hulking pick-up truck to match.

Because yeah, in much of the country, this “type” is sitting high, driving recklessly and tailgating as if all the risk is on you.

Caren Pistorius, of “Cargo” and “Light Between the Oceans,” is Rachel, the divorcing mom who picked today of all days to oversleep. She’s going to make her teen son (Gabriel Bateman) late for school. Again. She loses “my best client” because she’s late to the lady’s hair appointment. Again.

And matters aren’t made better by the distracted jerk in the pick-up who sits at the light and makes her even later. A blast on the horn doesn’t move him, so she has to peel around him. He glowers.

Of course he makes it his business to catch up, stop beside her and make his point.

“Don’t I get a courtesy tap?”

Maybe he’s got a point. But that’s the only one.

“I’ve been having a hard time lately.”

Oh yeah, bub? “Join the CLUB.”

It’s go-time — a mom in an aged Volvo trying to outrun or out-maneuver a raging psychotic in a giant Ford truck, just to get her kid to school.

After that? That’s when things turn deadly, the stakes are raised and the city streets (New Orleans, subbing for Any City) become a nightmare, not just of traffic snarl, but of being hunted by an aggrieved crazy person who had snapped long before he didn’t get his “courtesy tap.”

“Unhinged” isn’t quite undone by its endless instances of foreshadowing. But everything you see, from the household item Rachel’s houseguests (Juliene Joyner, Austin P. McKenzie) have misplaced to that thing she leaves in her car when she goes to gas up, is UNDERLINED so that we’ll be sure to “get it” when it plays a part in the coming mayhem.

Crowe is intense enough throughout, but his best moments might be the film’s opening, when we see that he’s already snapped and started his rampage in the wee hours of the morning.

The car chases are kinetic and wholly within the realm of believable. No “She must have had stunt-driver training to get out of that” moments. Suspense is heightened by keeping the cameras tight on the drivers as they’re taking these non-performance vehicles to their limits.

Conversely, every time the movie stops for scenes where the villain goes after those closest to Rachel, taunting her by phone as he has his “revenge,” “Unhinged” feels unmoored.

The bodies piles up, the cops are always a step or two behind and if they’d confined this thing to the cars and real-time carnage director Derrick Borte and screenwriter Carl Ellsworth (“Disturbia”) might have had another “Duel” on their hands.

Instead, the tension breaks, again and again.

Pistorius, looking too young to have a teen son, underplays the terror the way her character underplays her “concern” about being late all the time.

And the first movie to “reopen America’s cinemas” proves not worth the risk seeing it in a theater will entail.

MPAA Rating: R for strong violent content, and language throughout.

Cast: Russell Crowe, Caren Pistorius, Jimmi Simpson, Gabriel Bateman

Credits: Directed by Derrick Borte, script by Carl Ellsworth.  A Solstice release.

Running time: 1:30