The 70-mile stretch of dusty highway connecting Kirkuk to Sulaymaniyah in Northern Iraq looks like any other road in the world—except for the 70-plus gas stations lining the shoulder. Some look more like a temple. Or have gold-plated pillars. Or brandish a snappy set of Kurdish flags.

In a country with 140 billion barrels of crude oil reserve, pretty much anyone can start a gas station. Some families own a bunch. The economics of the business push prices as low as $1.60 per gallon. And everyone along Sulaimani-Kirkuk Road is selling pretty much the same stuff. So the filling stations have had to find some way to set themselves apart. The answer will be familiar to anyone who studies deer antlers or peacock plumage: It's all about the ornaments.

Photographer Eugenio Grosso visited the road last September, and the visual experience sent him grabbing for his camera. “A petrol station on its own is quite boring,” he says. “But these stations are all different, and different from what we expect.” Grosso hired a taxi driver and spent a day snapping photos of air pumps next to murals of fiery arrows.

Ostentatious roadside architecture has long been a hallmark of car-based societies. The architects Robert Venturi, Denise Scott Brown, and Steven Izenour figured it out in Learning from Las Vegas—if you want to impress someone speeding by in a jaunty automobile, you have to build to be seen quickly, and from a distance, which is to say big, bright, and tall. (See also: classic Los Angeles department stores and Sleeping Beauty's Castle.) For the Iraqi gas stations, some kind of weird architectural Darwinian sexual selection is at work; the boldest and brightest wins the thirsty car.

Grosso's series Oil City showcases an array of architectural frippery, from delicate ivory towers to sinuous, googie-style roofs. Some enterprising owners even rip well-known oil brands' logos—"BO" instead of "BP," "Shall" instead of "Shell." Humbler spots slap on bright stripes and a string of lights. Sure, the road has its share of shabby, single pump-and-hose places, but most do their best to lure in fickle drivers.

None of the roadside spectacle guarantees success. Grosso noticed more than one location looked a bit deserted. “Some looked like a gas station in a ghost village—someone sleeping in the shade, no customers there,” he says. Perhaps it's time to invest in some gold-plated pillars.