Initially, the first bus ran on route 105, which was new, running between Lai Chi Kok and Sheung Wan. However, Cross-Harbour Tunnel's environment was unsuitable for this model, as well as the fact that the towing of these buses by the tow trucks used by the tunnel authority could result in damage to the chassis, so entire fleet were reallocated to express routes running between Yuen Long and Tsuen Wan/Kowloon. The O305s were renowned for their speed and power, with a maximum speed of over 120 km/h reported.