Opened in 1978, it was once the major trunk route linking the northwest New Territories to urban Kowloon and is known for its frequent traffic jams and road accidents owing to its early design and heavy usage.

Expressway regulations apply from the junction with Wong Chu Road, where it widens to 3 lanes and climbs the hillside beside Sam Shing Hui.

The road had to be built along the winding coastline, and the steep terrain encountered required the construction of numerous viaducts, culverts and cuttings.

To save construction costs, the road was built with narrow carriageways and substandard geometry, causing frequent traffic accidents and subsequent congestion for a long period, and as a result speed limits reduced to 70–80 km/h (45–50 mph).

Since the road was opened, there have been various improvements carried out to meet the increasing traffic demand, such as the addition of uphill crawler lanes (Tsuen Wan Bound) at Sam Shing Hui, So Kwun Wat, Tai Lam Chung and Ting Kau.

The Highways Department has plans to carry out extensive reconstruction works on Tuen Mun Road that will include widening traffic lanes, improving horizontal curvatures and sightlines, and the installation of noise barriers.

To enhance the convenience of communicators travelling from New Territories to Kowloon or Hong Kong Island, Tuen Mun Road Bus-Bus Interchange had been under construction since 15 July 2010.

The bus broke through the parapet, and plunged into Ting Kau Village 35 metres (115 ft) below, resulting in 21 deaths (including the driver) and 20 injured.

The bus was later lifted back onto Tuen Mun Road and transported to the vehicle compound at Siu Ho Wan.