In August, 1988, the Burlington Northern Railroad presented a report on the results of their testing at the AAR Communication and Signal Annual Meeting. They stated that the accuracy of both systems over a six-month period was in excess of 99.99%. Based on the spectacular results from both systems, the Burlington Northern asked the AAR to form a committee to write an AEI standard for the North American rail industry, and suggested that the AAR use the current draft ISO standard for container identification as a starting point. A committee was formed by the AAR, charged with the development of an AEI standard. Railroads such as Norfolk Southern Railway, Union Pacific Railroad, CSX Transportation and Canadian National Railway began their own testing programs and reported the results to the AAR's AEI Committee. In August, 1989, the AAR informed various identification system vendors that Amtech's identification technology had been selected as the AEI standard. By the fall of 1989, the AAR's AEI Committee had selected a technology and defined the tag's data format. The only major question still unresolved was whether to place tags on the sides of the rail cars or underneath, each approach having advantages and disadvantages in cost and maintainability. It was finally decided by the AEI Committee in the summer of 1990 that a tag would be mounted on each side of each car. In July, 1990, the AAR Committee on Car Service sent a resolution to the O-T General Committee of the AAR to set a mandatory implementation date when all rail cars in interchange service would be tagged. The O-T General Committee is the highest operating committee within the AAR. The O-T General Committee requested that the AEI Committee perform a cost/benefit analysis on mandatory AEI implementation and recommend an implementation schedule. In October, 1990, the O-T General Committee approved the recommended AEI voluntary standard. With these recommendations, in August, 1991, the O-T General Committee of the Association of American Railroads voted to make the AEI standard mandatory. The mandatory vote was ratified by the AAR Board of Directors at their meeting in September, 1991. The mandatory period started on 1 March 1992, and ended on 31 December, 1994. By the end of this period all 1.4 million rail cars in North American interchange service were to be tagged. As part of the AAR's adoption of a standard based on Amtech technology, AAR required that