ADUO in F1: What is the engine regulation that could define course of 2026 Formula 1 season?

The 2026 Formula 1 season introduces ADUO, a new engine regulation acronym tied to the sport's most significant regulatory overhaul in its history, which includes new power units featuring a 50-50 split between electrical power and internal combustion engines. ADUO relates to rules governing engine development adjustments, intended to manage performance gaps that typically emerge when new engine regulations are introduced. The FIA will conduct its first review of engine performance following the Canadian Grand Prix to assess how the new regulations are playing out among competitors.