Complex sentence: The race featured both a Double U-turn and an ordinary U-turn in the same race for the first time, and also the first time that a U-turn board was placed at the Detour decision point, before the Detour itself.
Split into simpler sentences: The race featured both a Double U-turn and an ordinary U-turn in the same race for the first time. It was also the first time that a U-turn board was placed at the Detour decision point, before the Detour itself.