Pursuant to 第 374 章《道路交通條例》 [Cap. 374 Road Traffic Ordinance] —
單車 (bicycle) 指經設計及構造為使用踏板驅動的兩輪車輛。 [bicycle (單車) means a vehicle with 2 wheels designed and constructed to be propelled by the use of pedals.]
Which means —
單車或三輪車基本上享有和汽車一樣的使用道路的權利。同樣地，單車或三輪車使用者在使用道路時也有適當相應的責任，並須遵守一切交通規則（例如遵守所有交通標誌、交通燈號及道路標記），猶如他/她是在駕駛汽車一樣。 [A bicycle or tricycle basically has the same right to use a road as a motor vehicle. Needless to say, the rider of a bicycle or tricycle also has the duty to exercise due care when using the road and to comply with all traffic regulations (e.g. to comply with all traffic signs, traffic lights and road markings) as if he/she is the driver of a motor vehicle.]
“與騎踏單車有關” [Related to cycling], Community Legal Information Centre.
See also “道路使用者守則” [Road Users’ Code] by the Transport Department of Hong Kong:
騎單車 [Cycling]
單車被視為車輛。在道路上，騎單車者有同樣責任遵守適用於駕駛人的規例和規則。 [A cycle is regarded as a vehicle. A cyclist has the same obligation to follow the rules and regulations applicable to drivers when cycling on the road.]
一般駕駛人須遵守的交通標誌、交通燈號、道路標記及交通規則，你也必須遵守。 [You must obey traffic signs, traffic signals, road markings and traffic rules that apply generally to vehicles.]
除非巴士線上豎立了標誌，禁止單車駛入，否則你可沿巴士線行駛。 [You may use bus lanes unless there are signs banning cyclists.]
在「綠色人像」過路處前，如紅燈亮着，你必須在「停車」線前停車等候。只有當綠燈亮起及前路無阻時，方可繼續前進。無論何時，都應讓路給仍在過路的行人。 [At ‘Green man’ crossings, you must stop and wait behind the ‘Stop’ line if the red light is showing. You may only go forward if the green light is showing and the way is clear. Give way to any pedestrians still on the crossing.]
單車徑 [Cycleways]
如道路上有單車線，或路旁有單車徑，你必須在該處行駛，不准使用其他路面。 [If there is a cycle lane, or an adjacent cycleway beside the roadway, you must ride on it and not on any other part of the roadway.]
如單車徑旁有行人徑，不准駛上行人徑。 [If there is a footpath and a cycleway side by side, you must ride on the cycleway only.]
須按照交通標誌及道路標記指示的方向騎單車。 [Ride only in the direction indicated by traffic signs and road markings.]
在雙程單車徑上，靠左行駛。 [On a two-way cycleway, keep to the left.]
「終止」交通標誌或道路標記示明單車徑的終止。你要駛入或回到一般道路，與其他車輛共用路面。 [An ‘End’ traffic sign or road marking may indicate the end of a cycleway. You have to join or return to the normal road and ride with other traffic.]
停泊車輛的規則和指示一般也適用於停泊單車。在設有街燈的道路上，只可在指定供單車停泊的地方停泊單車。然而，任何單車均不得於同一泊車處停泊超過 24 小時。 [The rules and advice for the parking of vehicles generally apply to cycles. On a road with street lighting, you may only park your cycle in a parking place designated for pedal cycles. However, no cycle should be continually parked at the same parking place for more than 24 hours.]
Cf.《道路交通安全法》 [Road Traffic Safety Law] §51 of Mainland China:
非机动车应当在非机动车道内行驶；在没有非机动车道的道路上，应当靠车行道的右侧行驶。[Non-motorized vehicles should use the non-motorized vehicle lane; or, where no such lane exists, should proceed on the right side of the roadway.]