The T1 Group is formally defined as Prototype Cross-Country Cars and is divided into four primary sub-categories. T1.U, also known as T1 Ultimate, is reserved exclusively for vehicles powered by renewable energy sources; the Audi RS Q e-tron is a representative example of this sub-class. T1.1 covers four-wheel-drive prototypes running on conventional petrol or diesel fuels, while T1.2 covers two-wheel-drive variants under the same fuel rules. Competitors in T1.1 and T1.2 have included machinery such as the Mini John Cooper Works Buggy, the Toyota Hilux, and the Peugeot 3008 DKR. A fourth sub-class, T1.3, is open to vehicles built to SCORE International regulations, including the Hummer H3 buggy and other desert racing buggies that meet those standards.
All vehicles in the T1 Group fall within the broader car class weight limit of under 3,500 kilograms.
T1 vehicles represent the cutting edge of cross-country rally technology. Because they are prototypes rather than production-derived machines, their manufacturers and engineering teams have significant latitude in chassis design, suspension travel, and aerodynamic configuration. The result is vehicles capable of traversing sand dunes, rocky river beds, mountain tracks, and fine-powder terrain at sustained high speeds over marathon multi-day stages.
The class has historically attracted major factory programs. Mitsubishi dominated the Dakar car class for many years with purpose-built Pajero and Montero-based prototypes, while Volkswagen's Race Touareg won from 2009 through 2011. Peugeot returned to the Dakar under T1 regulations to win multiple editions with the 2008 DKR and 3008 DKR. Mini, Toyota, and more recently Audi with its electric RS Q e-tron have all fielded factory T1 efforts.
The FIA and FIM co-organise the World Rally-Raid Championship, which launched in 2022. The T1 class is the primary car category eligible for the manufacturers' and drivers' championships within this series. The championship incorporates the Dakar Rally as its flagship event alongside rounds such as the Abu Dhabi Desert Challenge, the Rallye du Maroc, and the Silk Way Rally, giving T1 factory teams and privateers a full season of top-level competition across different continents and terrain types.
The T1 class sits above the T2 category, which is limited to Series Production Cross-Country Cars such as the Toyota Land Cruiser and Nissan Patrol. It is also distinct from the T3 Challenger class for lightweight prototypes and the T4 SSV class for modified production side-by-side vehicles. The truck class, designated T5, covers vehicles weighing over 3,500 kilograms and has long been dominated by the Russian manufacturer Kamaz. T1 therefore occupies the specific niche of unlimited prototype car racing in off-road endurance competition, combining the engineering freedom of a prototype ruleset with the extreme demands of desert and cross-country navigation stages.