A past practice exists of hiring cops to direct traffic in connection with tree trimming when the past practice is unequivocal, clearly enunciated and readily ascertainable over a reasonable period of time. The union filed a grievance and claimed that the City of Bridgeport permitted a contractor to trim trees, without assigning an off-duty police officer to direct motor-vehicle traffic near the site, to protect public safety. The city objected that the past practice, for nearly two decades, has been that off-duty police officers are not routinely assigned to direct motor-vehicle traffic in connection with tree trimming. The municipal tree warden, Ray Dimizzo, credibly testified that for the previous 18 years the city has not routinely required the use of off-duty police officers in similar situations. Article 37 of the collective bargaining contract does not require the use of extra duty police officers to direct motor vehicles in the vicinity of tree trimming. "The Union," wrote the arbitrators, "has not demonstrated that the CBA requires hiring of police officers to work at a tree-trimming site." Arbitrators denied the grievance. Stephen Sedor represented the city. Eric Brown represented the union.