The Sonic Road is a fusion of the Wing, Sonia, and Bloody Roads. The Sonic Road was created and is used solely by Van Sahashi.
The Sonic Road essentially refines the Bloody Road's fierce attacks by adding the Sonia Road's flexibility and the Wing Road's ability to attack using winds. Riders of the Sonic Road often use fang and thorn based attacks, which are supplemented by the manipulation of winds. An example of this would be how somone could somewhat negate the Fang Regalia's sacrifice of the A-T's ability to jump by using the Wing Road to create a surface of air to stand on, therefore still being able to maneuver in mid-air.