Two fundamentally different futures for personal transportation emerge from this 1975–1979 corpus, and the gap between them is more revealing than either vision alone.

Gerard K. O'Neill imagines transportation liberated from its earthly constraints entirely. His "commutersphere" and "magneplane" aren't improvements on the car — they're replacements for the whole paradigm. The magneplane runs in vacuum, silent, at 300 mph, powered by unlimited electrical energy, computer-controlled to run at intervals of minutes without timetables. The travelsphere crosses intercontinental distances at supersonic speeds for a fifth of jet ticket prices, with no engines, no complex electronics, no petroleum. O'Neill's commuter arrives at a valley station a mile from home, sets their electric runabout to follow a buried wire home at walking speed, and boards the magneplane without consulting a schedule. This is transportation as infrastructure — elegant, collective, nearly frictionless, subordinating individual vehicles to system logic [O'Neill, The High Frontier, 1977].

Against this, Norman Spinrad's Pacifica gives us something that looks startlingly like 2025: a garage full of personal, quirky, individually chosen machines — fusion-powered scooters, jump-harnesses, powerskates, skimboards, one- and two-place floaters — each expressing the rider's personality and risk tolerance. Carlotta's floater is a metal disc with handlebars, a twist-throttle, and a float unit. "Getting there is all the fun." The city's morning traffic is a chaotic, layered mix of glideways, powered boards, cycles, and floaters weaving around each other, sorted by speed and daring rather than by infrastructure logic [Spinrad, A World Between, 1979]. This isn't a system. It's an ecology.

Joseph Weizenbaum, writing as a critic rather than a futurist, names the third path that actually happened — and diagnoses it as a failure of imagination. Computers were used to automate automobile production lines so consumers could choose from "millions of trivial options on their new cars" instead of being given vehicles that differed substantially from one another. The private automobile, he argues, could have been "downgraded as a means of personal transportation in favor of mass transit in, and passenger rail between, the cities" — but wasn't, because the incentive structure pointed elsewhere. Weizenbaum is describing our present from 1976 [Weizenbaum, Computer Power and Human Reason, 1976].

Mark Adlard's Multiface occupies a strange middle position: electric autos available for hire at Autoterminuses, recharged from power points, ranging from a doorless rectangular black box (cheap) to a glittering silver spaceship-on-wheels (two months' increments for a one-way trip). The society has solved emissions and noise — the gas turbine model in the tunnel runs in total silence after 200,000 kilometers, its only sound the stahlex-reinforced tires — but has preserved the class stratification of vehicle choice and the navigational nightmare of the Autocomplex interchange, a map so intricate it "frightened Will merely to look at it" [Adlard, Multiface, 1976].

[O'Neill, The High Frontier, 1977] contributes the most technically specific vision in the corpus. O'Neill's transportation thinking is embedded in his habitat engineering — the magneplane works because the habitat provides vacuum, unlimited electrical power, and computer control as default conditions. His commuter infrastructure is a byproduct of getting the physics right at larger scales. What he couldn't imagine: that the earthly political and economic structures he was trying to escape would follow humanity into space, or that the "unlimited low-cost electrical energy" premise would remain contested on Earth for another fifty years.

[Spinrad, A World Between, 1979] contributes the most sociologically accurate vision. The garage of personal transport devices — each with a different risk profile, each chosen by personality — maps almost directly onto the current urban micromobility landscape: e-scooters, e-bikes, one-wheels, electric skateboards, and now e-mopeds coexisting in chaotic street ecologies. Spinrad got the variety and the individualism right, and he got the cultural attitude right ("Getting there is all the fun") — the same ethos driving the current generation of last-mile devices. He missed that the energy source would be batteries rather than fusion, and that the chaos would generate intense regulatory conflict.

[Weizenbaum, Computer Power and Human Reason, 1976] contributes the sharpest diagnostic instrument. He's not predicting transportation futures — he's explaining why the better ones don't happen. The computer, in his account, gets recruited to optimize existing systems rather than to question whether those systems should exist. In 2025, this reads as prophecy: autonomous vehicle technology has been primarily developed to automate the individual car, not to replace it with something more rational. The "astronomical variety" of trivially different options is now the entire automotive market, extended to software features and subscription tiers.

[Adlard, Multiface, 1976] contributes the most ambivalent vision — a future that has solved some problems (emissions, noise, fuel) while preserving others (class stratification of access, infrastructural complexity). The self-profiling seat, the auto that follows coordinate inputs, the automatic headlights in the tunnel — these are recognizable as autonomous or semi-autonomous features. The Autocomplex map that defeats ordinary navigation is recognizable as every poorly-designed interchange ever built. Adlard imagined the technology improving without the system simplifying.

The corpus splits cleanly between two theories of how personal transportation would evolve. The first — represented by O'Neill — assumes that better physics and better systems thinking would eventually produce better infrastructure: collective, efficient, subordinating individual preference to elegant engineering. The second — represented by Spinrad and partially by Adlard — assumes that personal transportation would remain personal, that individual choice and individual expression would survive any technological transition, just with different machines underneath.

What neither theory fully anticipated is the mechanism by which the second path got locked in. Weizenbaum gestures at it: computers were used to deepen the existing automobile paradigm rather than escape it. By 2025, the pattern is clear — autonomous vehicle research spent two decades trying to make the individual car drive itself rather than asking whether the individual car was the right unit of transportation. Electric vehicles replaced the combustion engine while preserving every other feature of car culture: individual ownership, parking requirements, road infrastructure, suburban sprawl logic. The micromobility explosion Spinrad anticipated arrived, but as a supplement to cars rather than a replacement for them. O'Neill's infrastructure vision remains science fiction. Weizenbaum's critique remains current.

This configuration has significant gaps. All four authors write from wealthy, Western, urban perspectives — O'Neill's space habitats are explicitly designed for people who can afford to emigrate, Spinrad's Pacifica is a post-scarcity society, Adlard's Tcity is a managed welfare state, and Weizenbaum's critique assumes an American political economy. The corpus contains nothing from authors imagining transportation futures in the Global South, where the actual story of personal mobility in the early 21st century has been motorcycle proliferation, informal transit networks, and app-based ride-hailing transforming cities that never built the rail infrastructure the West abandoned.

The retrieved passages also show no engagement with the political economy of transportation infrastructure — who builds it, who profits from it, who gets excluded. O'Neill assumes the habitat's transportation system emerges naturally from its physics; he doesn't ask who controls the magneplane schedule or what happens when workers want to organize. Adlard's class stratification of vehicle access is present but not examined. A different vantage point — labor history, urban planning literature, transportation justice writing from this same period — would surface what this corpus cannot see: that transportation is always also a question of power, and the shape of that power determines which futures actually arrive.