Jump Boost field
From the Super Mario Wiki, the Mario encyclopedia
Jump Boost fields are entities that appear in Mario Kart Tour. They appear on 3DS Rainbow Road R and 3DS Rainbow Road R/T and are always paired with a ramp. They lift drivers upward, providing them with a Jump Boost, which is separate from the Jump Boost they receive when they drive off the paired ramp. Because of this, they function similar to air currents in the game, and are treated as such when completing challenges that require the player to ride on air currents a specific number of times.