Quota system


 * Citybus had ordered 62 MAN 24.310 during the testing of MAN 24.350 in 1997. Citybus decided to cancel the order due to the TD's policy on the number of vehicles. Those were purchased by KMB and Kwoon Chong Motors.
 * As the Transport Department for Hong Kong has promised to reduce the number of fleets, NWFB sold 30 of the Dennis Darts to FirstGroup in 2000. In October 2003, NWFB also sold 10 Dennis Darts to Kowloon Motor Bus (KMB).
 * As the West Rail Line, Ulu Pandan Line, Ma On Shan Line, North East Line, Punggol LRT and Sengkang LRT opened to traffic between 2003 and 2005, the Transport Department had requested KMB and SBS Transit to reduce the number of bus fleets. The first four batches of Enviro500 will require some delays after arrival.
 * In 2010, the first generation Citybus Dennis Tridents are already ageing. The Cityflyer has been expanded year by year, but the Transport Department has asked Citybus to reduce the number of fleets. Those buses already involved in accidents were not repaired for Dennis Tridents, so they were replaced by Enviro500 and Enviro500MMC, together with MAN NL262 being replaced by Enviro500s.
 * Since 2017, the franchised operators have entered the peak period of replacement of retired buses. Therefore, all bus operators have ordered large number of buses. As the Kwun Tong Line Extension, Downtown Line Stage 3, Tuas West Extesion and the South Island Line are open to traffic, the Transport Department strictly limits the number of new vehicles. Affected include the 50 Facelift body semi-luxury Enviro500 MMC 12 meters, and 25XX, 1543-1551, 5541-5543, and KMB two European Union Type 6 Enviro500 MMC 12 meters. One reason is that the Transport Department has vetoed and prohibited Long Win Bus from transferring any models to the KMB under registration)