New York City mandated yellow for all medallion taxis in 1967. The rule was intended to make licensed cabs easier for passengers to recognize and to distinguish them from unauthorized or unlicensed operators.
The policy helped turn yellow taxis into one of New York’s defining visual symbols. Before the mandate, taxi fleets could appear in a variety of colors, although yellow had already become associated with cabs through private companies and earlier experiments. Standardizing the color made it easier for riders to identify a legitimate vehicle amid dense city traffic.
The rule applied specifically to the city’s medallion taxis, the vehicles authorized to accept street hails. It should not be confused with every vehicle-for-hire in New York: livery cars and later green boro taxis have operated under different licensing and street-hail rules. Today, yellow taxis may pick up street-hailing passengers throughout all five boroughs, while green taxis were introduced primarily to improve service outside the traditional central business districts.