Until 1940, the New York City subway system was separated into three companies: the Interborough Rapid Transit Company (IRT), the Brooklyn-Manhattan Transit Company (BMT), and the Independent Subway System (IND). Even after all three companies were officially unified, changes to passenger-facing signage and wayfinding information progressed much more slowly. In 1957, graphic designer George Salomon submitted a proposal to the New York City Transit Authority (NYCTA) titled "Out of the Labyrinth." This proposal outlined several of the issues related to the sudden merging of the three companies and offered solutions to assist passengers, both local New Yorkers and tourists, in navigating the subway system more easily. In 1958, the NYCTA used Salomon's suggestions in their redesigned subway map, the first in the city's history to use a Beckian grid, a style named after Harry Beck who standardized the London Underground map, and featured eye-catching colors to distinguish operational routes in the three separate service divisions (IRT, BMT, and IND). This map design was used throughout the 1960s before being officially replaced with Massimo Vignelli's design between 1972-1978 and Michael Hertz's design in 1979, which remains largely the version still in use of as 2024.