Highway Accident Fairness Act of 2021 This bill makes staging a collision with a commercial motor vehicle a federal crime and modifies legal procedures for suits arising from commercial motor vehicle accidents. A person who operates a motor vehicle and intentionally collides with a commercial motor vehicle (or arranges for another person to cause such a collision) is subject to a fine, a prison term of up to 20 years, or both. If the collision results in serious bodily injury or death, the prison term may not be less than 20 years. With respect to legal procedures, the bill (1) requires a plaintiff in a suit concerning a bodily injury or death that involves one or more commercial motor vehicles to disclose the identity of any third party who is financing the litigation in exchange for a portion of the plaintiff's recovery, and (2) grants federal courts jurisdiction over such actions in cases where damages exceed $5 million.