Patronage across the Brooklyn Bridge increased in the years after it opened; a million people paid to cross in the six first months. The bridge carried 8.5 million people in 1884, its first full year of operation; this number doubled to 17 million in 1885 and again to 34 million in 1889. Many of these people were cable car passengers. Additionally, about 4.5 million pedestrians a year were crossing the bridge for free by 1892. Trolley tracks were added in the center lanes of both roadways in 1898, allowing trolleys to use the bridge as well. That year, the formerly separate City of Brooklyn was unified with New York City, and the Brooklyn Bridge fell under city control. Concerns about the Brooklyn Bridge's safety were raised during the turn of the century. In 1898, traffic backups due to a dead horse caused one of the truss cords to buckle. There were more significant worries after twelve suspender cables snapped in 1901, though a thorough investigation found no other defects. After the 1901 incident, five inspectors were hired to examine the bridge each day, a service that cost $250,000 a year. The Brooklyn Rapid Transit Company, which operated routes across the Brooklyn Bridge, issued a notice in 1905 saying that the bridge had reached its transit capacity.