Over the course of 1974, Kraftwerk cropped their long hippy hair and adopted smart business suits. It was a self-consciously German rebranding, mixing deadpan humour with serious artistic intent. An elegant riposte to Anglo-American pop hegemony, Autobahn was a defiant reclaiming of a rich cultural hinterland that spanned Schubert and Stockhausen, Bach and Beuys. “Ralf had a kind of German idea in mind,” Flür recalls. “Germany also needed something like The Beach Boys. Something with self-understanding and immaculate presence, after the ugly wars that our parents had inflicted on the world. Something positive and youthful, that freed us from the stench of the past.”

Autobahn is not quite a fully electronic album, though everything Kraftwerk recorded afterwards would be. Featuring vestigial traces of violin, flute, piano and guitar, it was mostly recorded over the summer of 1974 at Conny Plank’s newly established farmhouse studio in Wolperath, 20 miles southeast of Cologne. Sometimes Plank would drive his 16-track mobile recording truck to Kraftwerk’s fabled Kling Klang headquarters on Mintropstrasse in downtown Düsseldorf, parking in the yard outside and running wires from his mixing desk into the building.

Opening with a clunking car door and a churning ignition sound, the full LP version of “Autobahn” is a serene 22-minute journey of swerves and curves, gentle gradients and blaring horns, tarmac-rumbling rhythms and doppler-shift effects that simulate the sensory whoosh of passing vehicles. Unspooling like a ribbon of road stretching to the horizon, it rolls on a warm rhythmic throb that accelerates and decelerates at different points, with a full breakdown midway through.

Plank and Kraftwerk painstakingly assembled Autobahn from multiple sound sources, primitive samples and field recordings. They made extensive use of Hütter’s new Minimoog plus an EMS Synthi, ARP Odyssey and other early synthesisers. To suggest passing vehicles, they used tape-reversed bursts of white noise. The song’s harsh, sibilant, sinister-sounding vocal chants came from a Robovox, a programmable speech synthesiser built by Schneider. A thousand harmonising details converged into a marathon artificial road trip. “The white stripes on the road, I noticed them driving home every day from the studio,” recalls Hütter. “Then the car sounds, the radio – it’s like a loop, a continuum, part of the endless music of Kraftwerk. In ‘Autobahn’ we put car sounds, horn, basic melodies and tuning motors. Adjusting the suspension and tyre pressure, rolling on the asphalt, that gliding sound – pffft pffft – when the wheels go onto those painted stripes. It’s sound poetry.”

The simple, spare, circular lyric to “Autobahn” was composed by Emil Schult in a single day, then tweaked by Hütter. The seven-line nursery rhyme describes the view over a sunlit valley, the colours of the grey road with its green-edged white stripes, and the sound of a car radio which plays the song’s refrain back to itself. A droll, self-referential feedback loop. But of course, the lyric mostly consists of the single childlike chant “Wir fahren fahren fahren auf der Autobahn” (“We drive drive drive on the motorway”) repeated over and over. Anglophone listeners were quick to make phonetic connection with the refrains in “Fun Fun Fun” and “Barbara Ann” by The Beach Boys. But although Kraftwerk were fans of their car-loving California cousins, Hütter insists “Autobahn” is not a sly homage.

“In the case of The Beach Boys, ‘Fun Fun Fun’ is about a T-Bird,” Hütter explains. “But ours is about a Volkswagen or Mercedes. The quote is really more ethnic. People said: are you doing surfing on the Rhine? Yes, maybe, but we don’t have waves. It’s like an artificial joke. But no, it’s not a Beach Boys record, it’s a Kraftwerk record.”