In DART v. Amalgamated Transit Union, 273 S.W.3d 659, 660 (Tex. 2008), DART and its employees' union operated under a 13(c) arrangement. Id. The court, in holding 13(c) did not preempt DART's immunity from suit under state law, noted that Texas law prohibits a state political subdivision from collective bargaining with public employees. Id. at 661 (citing Tex. Gov't Code Ann. 617.002(a), (b) (West 2012)). The union in DART did not challenge the applicability of section 617.002. Id. Thus, DART stands for the proposition that a 13(c) arrangement does not preempt the applicability of section 617.002. See id. at 660-61.