It came as a relief when Jessica Lange finally admitted that her driving was a bit unpredictable. I was afraid to bring it up from the passenger seat.

“My kids used to say, ‘Mom, pick a lane!’ ” the two-time Oscar winner said, chuckling.

On a day with silvery light coming through clouds and Lake Superior to our right, she was piloting us northward from Duluth on Hwy. 61. We had a perfect car for a road trip: her green 1967 Mercedes-Benz 250S — which used to be owned by movie director Milos Forman, who used it to flee the 1968 Soviet invasion of Czechoslovakia — heavy as a tank and with seat belts of questionable functionality.

But Lange knew where she was going. For her, a Minnesota native who summers in what she called “a cabin” along Lake Superior’s North Shore, Hwy. 61 was more than a conveyance; it was a creative wellspring dating back to her childhood.

We went through towns with names like Castle Danger and Beaver Bay, past dense stands of trees and signs for smoked fish and homemade pies. The road is the subject of her latest book of photographs, “Highway 61,” which came out Oct. 1.

The 84 black-and-white photographs document all manner of life along the highway, which runs — first as a state road, then for most of its route as a U.S. highway — from the Canadian border to New Orleans. Lange has spent time over the past six years documenting all eight states where the highway unfolds.

She was born in Cloquet, and the route was a central artery for her family, but the book also chronicles the changes she has witnessed — stretches of the road that she describes as “empty, forlorn, as if in mourning for what has gone missing.”

Lange, 70, who starred in “Tootsie” and “American Horror Story,” among dozens of other movies and TV shows, hasn’t given up acting. Her latest production is “The Politician,” which has launched a new season on Netflix.

But photography is much more than a hobby for her, as I discovered on our road trip. Wherever we stopped, she paused to take photographs.

In the book’s afterword, Lange wrote about how her first album purchase was “Highway 61 Revisited,” released in 1965 by fellow Minnesotan Bob Dylan.

When she left home at 18, she jumped on Hwy. 61 and “headed south out of town,” she wrote, “on my way to Europe and beyond, the start of a new life.”

Capturing small moments

The photographs are grainy, suffused with intense light and shadow, capturing small moments featuring people, road signs, horizons, carnivals, diners. The book’s cover has one of her most-striking images, an African-American child looking right at the camera with an intense gaze.

“It’s expressive, emotional street photography,” said veteran dealer Howard Greenberg, who is giving Lange a show in his New York gallery. “It’s not a tourist view. She gets close to her subjects.”

At first glance, “Highway 61” may evoke the work of William Eggleston and Robert Frank. Lange knew both of them personally. But her favorite practitioner is someone less famous, Czech photographer Josef Koudelka, noted for his work with high-contrast, black-and-white images.

“I never use a flash or carry lights or anything,” Lange said when we stopped for lunch in Beaver Bay. “I never crop. I think it’s a conceit. I always loved that Henri Cartier-Bresson showed you the whole image.”

Lange studies photography — she said she had been reading Roland Barthes’ “Camera Lucida” — but her take on the medium is more instinctual than theoretical.

“It’s storytelling,” Lange said.

Sarah Paulson, her co-star from “American Horror Story” and a close friend, has four of Lange’s images on the walls and is soon getting a fifth.

“When you’re seeing through Jessica’s lens, it’s immediate and feels visceral,” Paulson said. “It’s the same alchemy that makes her so extraordinarily powerful as an actress.”

Photography, and what it captures, has potency for Lange, who recounted a moment when she was 5 or 6, looking through a box of photos in her grandparents’ attic.

“One man was looking directly into the camera, and his gaze was so arresting to me as a little girl,” she recalled. “And I thought, ‘I’m connecting to him somehow.’ That’s the power of photography.”

A late bloomer

At the University of Minnesota, photography accidentally ended up in her curriculum when she couldn’t get into a painting class. But her passion for taking photographs had to wait until after her movie career took off.

She started taking pictures seriously in the 1990s, when her partner, playwright and actor Sam Shepard, came back from a trip to Germany with a Leica as a gift. She saw it as a way to take high-quality pictures of their two children, and her practice grew from there.

Her fame has not hindered her approach as a street photographer, a genre that typically relies on the camera-wielder being unobtrusive. Anne Morin, whose company, diChroma Photography, produces traveling photography exhibitions and has sent Lange’s work on tour, said that she works very fast. Even in northern Minnesota, where a Lange sighting is not that unusual, it can take people a few seconds to connect the face they are seeing to the movies they have seen. By then, she’s gotten the shots she wants.

I saw this firsthand at Black Beach Park in Silver Bay — so named for its tiny black stones. Encountering a mother and two children, her camera suddenly was up and she snapped several pictures of the family. “The boy turned as I was taking it, and it produced a great shape,” she said.

In the age of Instagram, when “everyone is a photographer,” as she put it, it’s a treat for her to take control of the lens. It’s a break from fretting that someone is taking her picture in a supermarket: “I don’t have to worry about being absurd.”

I wondered, given her success in acting, how seriously she wanted to be taken as a photographer.

“You know how this works,” she said, sounding not bitter but realistic. “You’re an actress, therefore you’re not considered a photographer. So you’re an actress who photographs. It’s a kind of mindless categorizing; if you’re one thing, you can’t be another.”

But Midwestern optimism, and what I gleaned was one of Lange’s core personality traits — what Paulson called her sense of “freedom and abandon” — won the day.

“I’ve got a day job,” she said, and laughed. “I just love taking photographs. That’s the only reason I do it.”