八達通
Bus-bus interchange became a common practice since the 1990s. In 1991 bus-bus interchange was introduced for Shing Mun Tunnel routes. Later on bus-bus interchange using transfer tickets was introduced on some overnight routes and Tai Lam Tunnel routes. With the Octopus card being accepted on some franchised bus routes since 1997, the first bus-bus interchange using Octopus card was first introduced in 1999.