During the Great Depression, New York City had as many as 30,000 cab drivers, creating fierce competition and raising concerns about vehicle safety and maintenance. Efforts to create a taxi monopoly were abandoned after allegations that Mayor Jimmy Walker had accepted a bribe from a major taxi company.
The city's taxi industry was formally regulated in 1937 under the Haas Act, signed by Mayor Fiorello H. La Guardia, which created the medallion system still used today. By the mid-20th century, yellow cabs had become synonymous with New York, serving millions of riders and appearing in countless films, television shows, and photographs.