Kansas law was settled a decade before, so the state can’t claim that the officer’s allegedly reasonable mistake of law makes this stop reasonable under Heien. State v. Lees, 2018 Kan. App. LEXIS 64 (Nov. 16, 2018):
Applying Heien and Pianalto, the State asserts that Sperry’s mistake of law about the brake light violation was objectively reasonable, rendering the traffic stop lawful. But as Lees points out in his brief, the statutes at issue in Heien differ from the statutes at issue here. In Heien, it was ambiguous how many functioning brake lights the statute required; but the Kansas statutes are clear that only two functioning brake lights are required. Reading K.S.A. 8-1708(a) and K.S.A. 8-1721(a) together, no reasonable officer would think that the law required brake lights to be spaced laterally as far as practicable and mounted at the same height, as Sperry wrongly believed; neither statute suggests such a requirement in any way. Granted it may be reasonable for the average citizen to believe the law likely requires left and right brake lights, but law enforcement officers are not average citizens. They must reasonably study the laws they are duty bound to enforce. See Heien, 135 S. Ct. at 539-40.
In addition to the fact that the applicable Kansas statutes are unambiguous, the Kansas Supreme Court has previously interpreted them as well, over 10 years ago. In Martin, a driver’s license suspension case, a law enforcement officer stopped a driver for having a malfunctioning brake light, although two other brake lights were working. The city ordinances that prompted the stop were identical to K.S.A. 8-1708 and K.S.A. 8-1721. The Martin court found that two operational brake lights were sufficient under Kansas law. 285 Kan. at 637. The court determined that an officer’s mistake of law may invalidate a traffic stop under the Fourth Amendment. 285 Kan. at 639. But the court went on to conclude that the exclusionary rule did not apply to a driver’s license suspension proceeding under the circumstances of the case. 285 Kan. at 639-46.