|New South Head Road was completed in 1839 at least as far as the signal station at Vaucluse. In May 1848 the South Head Roads Trust Act was passed, and this enabled the Government to appoint a Road Trust to control several roads and construct tollgates. The roads under the Trust's jurisdiction included New and Old South Head Roads and Point Piper Road. It was not until the passage of the Local Government Act of 1906 that the Government gave councils in the Eastern Suburbs the authority to take charge of the major roads running through their local government areas.
During the late nineteenth century the volume of traffic along New South Head Road steadily increased. Tramlines were constructed extending out from the City of Sydney and by the 1890s a tramway terminus was situated at the western end of Rose Bay. The tram service was extended as far as Dover Road in 1900, and was pushed out to Watson's Bay Wharf by 1909.
As residential development consolidated in the area around Rose Bay, improvements were contemplated for New South Head Road, perhaps spurred on by complaints received by residents concerning its deplorable condition. Council was certainly purchasing land for road widening purposes by the beginning of 1917, and a New South Head Road Improvement Committee was formed to oversee the proposed works, which included resumptions, realignment of parts of the road and widening it to 100 feet (30.48 metres).
The road widening works took place over a number of stages, and in 1923 Council submitted a request for a grant and loan to the Department of Local Government to cover the cost of widening the road in several places: at the junctions of New South Head Road and Darling Point Road and Cross Street, in the vicinity of what is now Cranbrook School to Victoria Road, and improvements and widening between Rose Bay Park and Lyne Park.
In June 1924 the prominent architect Herbert E. Ross offered his services as honorary consulting engineer for the works between Rose Bay Park and Lyne Park, including the Rose Bay sea wall and Promenade, acting in conjunction with Council's own engineer (Howard, 2001:5).
On Friday 19 February 1926 a ceremony was held during which the widened road was opened and the lights along the Promenade switched on (Howard, 2001:6). The completed road widening was officially placed under the management and control of Woollahra Council on 17 March 1926, but during 1928 and 1929 the Main Roads Board was given wider responsibilities and so New South Head Road was proclaimed a main road under the Local Government Act and placed under the control of the Board.
The tram service from the City of Sydney to Watsons Bay was closed on 10 July 1960 and replaced by buses.