The push for a new formula was driven by existing WRC manufacturers who sought to align the championship with changes in consumer technology preferences while simultaneously reducing the spiralling costs of the outgoing World Rally Car. The FIA approved the transition in June 2018 as part of a broader restructuring of the Rally Pyramid, the hierarchical system of FIA rally categories.
Despite the word "Group" in the official designation, Rally1 comprises a single class with no subclasses. The term Rally1 may be used interchangeably with Group Rally1.
Rally1 cars are defined under Article 262 of Appendix J of the FIA International Sporting Code. Two characteristics set them apart from their predecessors.
First, the cars are Category II purpose-built competition vehicles. Unlike previous WRC machinery, they do not require homologation in Group A or N and carry no minimum series-production requirement. They must, however, be visually identifiable as based on a production road car model. Both tubular space-frame chassis and production bodyshells are permitted, while a common safety cell structure — designed in partnership with the FIA — is mandatory across all entries.
Second, Rally1 retained the existing 1.6-litre turbocharged global race engine producing approximately 386 PS, continuing the powertrain architecture of the World Rally Car era.
Other technical changes introduced with Rally1 include the mandated use of synthetic fuels claimed to be sustainable and renewable, and the deployment of Artificial Intelligence Safety Cameras (AISC) on special stages to monitor for out-of-place spectators and other hazards. Mechanically, suspension travel was reduced, the gearbox was simplified from six to five speeds (aligning with Rally2 cars), flappy-paddle gear shifters were removed, the active central differential was eliminated, liquid-cooled brakes were banned, and various aerodynamic components — including the rear diffuser and hidden cooling ducts — were removed to cut costs and reduce damage bills.
The hybrid electric power unit is supplied to all competing manufacturers by a single third-party provider, Compact Dynamics, with battery cells sourced from Kreisel Electric. This standardised approach prevents manufacturers from developing competing hybrid architectures and controls costs.
The system serves two roles. On liaison sections between stages, it powers the car in fully electric mode when the rally roadbook designates an electric-only zone. During special stages, it provides a boost of up to 100 kW (approximately 136 PS) alongside the combustion engine. It also recovers kinetic energy under braking.
Drivers choose from three pre-set deployment strategies and three recuperation strategies before the start of each special stage. Crucially, once a stage begins, the driver cannot alter when the electric boost is deployed — the system operates automatically according to the selected setting.
The hybrid unit added 84 kg to the cars' gross weight. Due to the system operating at 750 volts, all Rally1 cars carry HV identification markings — white letters on a red background — on the door panels. Crews are required to carry high-voltage gloves in case of an electrical incident.
The hybrid system was discontinued from the 2025 season after teams concluded that the cost of repairing damaged units had become prohibitively expensive.
Rally1 cars are exclusively permitted in the World Rally Championship and must be entered by manufacturer teams. They may appear at individual rallies outside the WRC when entered by manufacturers, but cannot score championship points in any other series.
Rally1 marked the most significant technical overhaul of WRC machinery in over a decade, bringing hybrid technology to the pinnacle of rally competition for the first time. The move to standardised hybrid hardware was a deliberate cost-control measure, aimed at keeping manufacturer participation viable. When the hybrid system was retired in 2025, the fundamental architecture — purpose-built Category II cars with the 1.6-litre global race engine — remained the basis of the top WRC class.