Cheaper Than Walking? The Shocking Running Costs Of The Trident Bubble Car Revealed

[Trident] The automotive industry’s history is not just about bigger cars and more powerful engines. Innovations driven by urban congestion, fuel efficiency, and new ideas about personal mobility have sometimes produced vehicles with unconventional sizes and shapes. Long before compact city cars became a mainstream segment, some manufacturers were already challenging the assumption that cars must be large, often in radical ways. These ultra-compact production vehicles balanced practicality with experimental design, earning a unique place in automotive history. Here are five of the smallest and most unconventional mass-produced cars ever built.

[REVAi] India’s REVAi was an early pioneer that brought the micro electric vehicle concept to market. Sold in the UK as the Reva G-Wiz, this quirky car was produced from 2001 to 2012 and looked like a child’s doodle brought to life.

[REVAi] With a tiny 67-inch (1,700 mm) wheelbase and an overall length of just 102 inches (2,600 mm), it did not even qualify as highway-capable in some jurisdictions. Its rear-mounted 13 kW electric motor delivered a modest 50-mile (80 km) range, later extended to 75 miles (120 km) with a lithium-ion battery upgrade. Despite its limited performance and questionable build quality, more than 4,600 units were sold across 26-plus countries, establishing the REVAi as a trailblazer in the ultra-compact EV segment.

[Vespa 400] This diminutive car marks the only four-wheeled venture from the iconic scooter brand Vespa. Produced from 1957 to 1961, it was designed in Italy but manufactured in France by ACMA.

[Vespa 400] The Vespa 400 featured a folding soft top and minimal cargo space in its two-seater layout, offering limited practicality even by the standards of its day. With a 66.7-inch (1,693 mm) wheelbase, 112.2-inch (2,850 mm) overall length, and a featherweight 793-pound (360 kg) curb weight, it made even the tiny Fiat 500 look substantial. Powered by a 0.4-liter two-stroke twin-cylinder engine paired with a three-speed manual transmission, the Vespa 400 was marketed as an affordable, easy-to-park urban runabout. More than 30,000 units were produced during its short run.

[Trident] The British-made Trident stands out as one of the most futuristic microcars of its era. With a transparent bubble canopy, this three-wheeler looked like a cross between a go-kart and a miniature aircraft. It was powered by a single-cylinder, two-stroke DKW moped engine producing just 4 horsepower, and it was promoted with the bold claim of being “cheaper than walking” thanks to its ultra-low running costs.

[Trident] At only 74.8 inches (1,900 mm) long, the Trident delivered an impressive 99 miles per gallon (42 km/ℓ), rivaling modern scooters. More mobile capsule than car, it perfectly captured the experimental spirit of the microcar era.

[Isetta Microcar] The Isetta is arguably the most commercially successful vehicle on this list. Introduced in Italy in 1953, it featured a distinctive front-opening door and an extremely narrow rear track. Despite measuring only 90.2 inches (2,290 mm) in length, it became a sensation in post-war Germany, prompting BMW to license the design for local production.

[Isetta Microcar] Multiple versions were produced using either Iso or BMW motorcycle engines. BMW alone manufactured more than 160,000 Isettas. The Isetta’s design and underlying concept continue to inspire modern microcars, including the Microlino.

[P50] The P50 holds the title of the smallest mass-produced car in history. Built from 1962 to 1965, this three-wheeler was marketed as being able to carry “one adult and a shopping bag.” With an astonishingly short 53.9-inch (1,370 mm) overall length and a weight of just 130 pounds (59 kg), it was light enough to be lifted and moved by hand.

[P50] That party trick gained global attention after the P50 appeared in a 2008 television broadcast. Like the Trident, it used a single-cylinder, two-stroke DKW moped engine. Today, replicas of the P50 are produced in both electric and internal-combustion versions, staying faithful to the original’s spirit and proportions. These vehicles are far more than curiosities or failed experiments. They represent radical interpretations of urban mobility, and they can be seen as precursors to today’s electric scooters, ultra-compact EVs, and broader micro-mobility solutions. As small and unconventional as they look, the questions they raised still matter: How small can a practical car be, and what truly counts as the minimum viable unit of personal transportation?