Sai Yeung Choi Street
As the MTR was built in the 1970s, and some exits of the Mong Kok Station had occupied the right lanes of Argyle Street from Sai Yeung Choi Street to Portland Street, thus the government at the time had made the control in effect: vehicles can only travel westbound in uni-direction between the streets mentioned above. As a result, vehicles from Tai Kok Tsui via Argyle Street, eastbound towards Kowloon City, shall make a left turn to Reclamation Street, then turn right into Mong Kok Road. After crossing the junction between Mong Kok Road and Nathan Road, one shall turn right to either Sai Yeung Choi Street or Sai Yee Street in order to lead back to Argyle Street. For the same reason, vehicles are not allowed to make a right turn directly from Nathan Road to Argyle Street, and must follow the route described above.