11 Va. Admin. Code § 10-150-60
No driver shall, without good and sufficient reason, refuse to drive a horse when ordered by the stewards to substitute for another driver. When a driver is programmed to drive a horse and removed at his request, he shall not be permitted to drive another horse in the same race.
§ 59.1-369 of the Code of Virginia.
Derived from VR662-05-02 § 2.5, eff. July 15, 1991.