Constructed as part of Route 2, it links Diamond Hill, New Kowloon with Siu Lek Yuen, Sha Tin, New Territories East.

[8] The Tate's Cairn Tunnel is a BOT (build, operate, transfer) infrastructure project funded 100% by the private sector.

The BOT franchise was awarded to the Tate's Cairn Tunnel Company Limited for a period of 30 years by the Hong Kong Government in 1988.

[9] Under the terms of the BOT, the franchisee is responsible for the construction and operation of the tunnel until the end of the franchise period.

During the franchise period, the company was allowed to earn a reasonable but not excessive return through the collection of tolls.