per department policy, was for legitimate law enforcement purposes). b. Reasonableness of length of delay When a traffic stop detention is prolonged by a reasonable delay to comply with legitimate police policy, no Fourth Amendment violation has occurred. See Belcher, 244 S.W.3d at 539; Hartman, 144 S.W.3d at 573. But the duration of the delay must be reasonable in light of the law enforcement purposes served. Texas courts of appeals that have reviewed delays for the same law enforcement purposes at issue here — increased experience and expediency in conducting DWI investigations and the need to have officers available to respond to emergency calls — have found delays of twenty minutes or more were reasonable with respect to the public policies served. See Belcher, 244 S.W.3d at 541-42 (<HOLDING>). The delay here was approximately fifteen
holding twentyseven minute delay while waiting for dwi officer did not violate fourth amendment holding that legitimate law enforcement interests were served by local police officers delay while waiting for state police officer to arrive to conduct dwi investigation because state officers had more dwi experience and local officers needed to be available to respond to emergencies holding that delay while awaiting arrival of dwi enforcement officer even though officer who initiated the stop was qualified to perform dwi investigation was for legitimate law enforcement purposes because dwi officer brought greater expertise to scene and could complete dwi investigation more rapidly holding that delay while awaiting arrival of dwi enforcement officer was for legitimate law enforcement purposes because dwi officer was more experienced and could complete dwi investigation faster holding delay of thirty to thirtyfive minutes waiting for state police to conduct dwi investigation during which time some investigation by local officer occurred did not violate fourth amendment