A 1960s Citroën DS traveling at 80 mph without a driver controlling its steering sounds remarkably ambitious, especially considering the computers and sensors available at the time. AutoSion explores how Britain's Road Research Laboratory developed an experimental autonomous driving system using buried guidance cables and the Citroën's unusual hydraulic technology. Presented by John, the documentary traces the evolution of driverless vehicles from primitive radio-controlled demonstrations in the 1920s to modern autonomous systems, revealing how engineers approached a familiar technological challenge using solutions that now seem surprisingly unconventional.
The historical introduction establishes an important distinction between remote-controlled vehicles and genuinely autonomous machines. Early experiments involving a three-wheeled military vehicle and Francis Houdina's modified 1925 Chandler demonstrated that automobiles could operate without someone visibly occupying the driver's seat, but they still required human control from another location. The discussion then moves through General Motors' 1939 Futurama exhibition, its extravagant gas-turbine concept car, and subsequent American experiments involving roadway guidance systems. John's humorous commentary makes these developments entertaining while explaining why impressive demonstrations did not necessarily translate into practical transportation technology.
The documentary becomes considerably more interesting when attention turns to Britain's Road Research Laboratory at Crowthorne. Rather than using complicated radio-transmitter networks, researchers developed a guidance system based on signal cables buried beneath the road. Sensors mounted on the vehicle detected deviations from the cable's magnetic field, allowing the steering system to make corrections automatically. John explains this arrangement in accessible terms, establishing both its advantages over earlier approaches and its fundamental limitation: the vehicle could only follow specially equipped roads. The reported installation of approximately two and a half miles of guidance cable and successful testing at speeds reaching 80 mph provide compelling examples of the project's technical ambition.
The preserved Citroën DS at the Science Museum's Science and Innovation Park gives the documentary its strongest physical connection to the engineering involved. John examines the car's extensive internal equipment, including its substantial control hardware, sensor arrangements, electrical components, and specialized steering mechanisms. The explanation of why researchers selected the DS is particularly valuable. Its interconnected hydraulic systems made automated control more achievable through electro-hydraulic servo valves than it would have been in conventional vehicles with separate mechanical arrangements. The discussion of suspension adjustments compensating for deviations during cornering adds another useful layer, demonstrating that maintaining a vehicle's course required more than simply following an electromagnetic signal.
Visiting the enormous museum storage facility also contributes to the presentation's appeal, although the occasional jokes and promotional interruptions briefly distract from the engineering discussion. More importantly, John shows appropriate caution when examining claims that the Citroën was subsequently tested on a nine-mile section of the M4 motorway before it opened to public traffic. Rather than presenting this story as established history, he acknowledges being unable to locate photographic or video evidence confirming the installation or testing. This willingness to question an appealing historical anecdote strengthens the documentary's credibility, even though the central research project would benefit from similarly detailed references supporting its performance figures and technical conclusions.
The later sections provide a useful overview of how autonomous driving progressed beyond infrastructure-dependent guidance systems. Japan's 1977 camera-based experiments, European research involving Mercedes vehicles, and American developments incorporating LIDAR illustrate the gradual movement toward cars capable of interpreting their surroundings independently. The account ultimately connects Stanford's autonomous vehicle research with Google's self-driving project and the emergence of Waymo. However, this chronology sometimes compresses complicated technological developments into a sequence of headline achievements. The discussion of the DARPA competition is particularly imprecise, and the distinctions between lane-following demonstrations, restricted experimental autonomy, and comprehensive driverless operation deserve more careful treatment. Likewise, the suggestion that radar, electronic controls, and later technologies made autonomy straightforward understates the continuing difficulty of real-world vehicle perception and decision-making.
Pros
- Explores an often-overlooked British contribution to autonomous driving, focusing on the Road Research Laboratory's experimental Citroën DS and its infrastructure-based guidance system.
- Clearly explains how buried signal cables, magnetic-field detection, and automatic steering corrections allowed early driverless experiments to function.
- Provides particularly interesting engineering detail about the Citroën DS's hydraulic systems, electro-hydraulic controls, and suspension adjustments.
- Strengthens the historical presentation through access to the preserved experimental vehicle and the Science Museum's extensive collection.
- Places Britain's research within a broader technological progression, from remote-controlled vehicles and General Motors concepts to camera-based navigation and modern autonomous systems.
- Acknowledges the lack of supporting evidence for the reported M4 motorway experiments rather than presenting the story as unquestionable fact.
- Combines accessible technical explanations, enthusiastic narration, and lighthearted humor without losing sight of the central historical subject.
Cons
- Provides limited identification of primary research documents or technical records supporting several historical performance claims.
- Occasionally blurs the distinctions between remote control, automatic road following, experimental autonomy, and modern driverless capability.
- Compresses later autonomous vehicle developments into an abbreviated chronology, including an imprecise account of the DARPA competition.
- Gives insufficient attention to practical obstacles beyond infrastructure costs, particularly obstacle detection, unexpected road conditions, and independent decision-making.
- Brief merchandise promotions and occasional comedic tangents interrupt an otherwise engaging technical narrative.
AutoSion delivers an entertaining and informative exploration of early autonomous driving, with the experimental Citroën DS providing a fascinating example of how unconventional automotive engineering helped overcome technological limitations. The preserved vehicle, accessible explanations, and historical context make the presentation especially rewarding, while the unresolved motorway claims and occasionally imprecise chronology prevent it from becoming a fully authoritative account. Nevertheless, it succeeds admirably in demonstrating that the pursuit of driverless transportation began long before today's sophisticated sensors and software.
