T&TC Paper No. 13/2018 (For information)

Southern District Council Traffic Conditions along Corridors between Southern District and North-Shore of Island

Purpose As per the request by the Traffic and Transport Committee of the Southern District Council, this report is prepared to annually review the updated traffic conditions of the three major corridors in the Southern District, namely the Aberdeen Tunnel, Road and , and to suggest improvement measures when it is necessary.

Traffic Conditions of Three Major Corridors 2. Based on the traffic flow data of Transport Department collected in 2016, the traffic conditions of the three mentioned corridors are as shown in the following table.

Aberdeen Pok Fu Lam Tai Tam Road Volume/Capacity Tunnel Road ratio (v/c) ratios1 NB SB NB SB NB SB

AM Peak 0.75 0.77 0.64 0.55 0.58 0.40

PM Peak 0.56 0.66 0.69 0.49 0.41 0.36

3. As revealed from the above table, the traffic conditions of the three major corridors are normal, and the corridors are still having spare capacities. Nevertheless, affected by the traffic conditions of the downstream areas, from time to time traffic congestion appears along the corridors.

Aberdeen Tunnel 4. The v/c ratios of Aberdeen Tunnel are normal. However,

1 The capacity here refers to the design capacity of the road. A v/c ratio of 1.0 or less means that the road has sufficient capacity to cope with the volume of vehicular traffic under consideration. A v/c ratio above 1.0 indicates the onset of mild congestion. there are occasional congested situations resulting in intermittent tunnel closure. Upon the commissioning of South Island Line (East), the number of intermittent tunnel closure and traffic flow were decreased when compared to that prior to commissioning. For details, please refer to item D of TTC Paper No. 11/2018.

Tai Tam Road 5. The v/c ratios of Tai Tam Road are normal. However, there are occasional traffic congestions at the section of Tai Tam Road above the Tai Tam Reservoir Dam. As the width of the road is about 5m only, it is difficult for two large vehicles to pass by concurrently and they may have to reduce the speed when passing by. To improve the situation, the Department has carried out traffic signal trials last year and had extended the prohibition hours for southbound goods vehicles over 3 tonnes from entering the concerned road section in January 2018. For details, please refer to TTC Paper No. 8/2018.

Pok Fu Lam Road 6. The v/c ratios of Pok Fu Lam Road are normal, and are the lowest amongst the three corridors. Under normal circumstances traffic congestion along Pok Fu Lam Road is not commonly seen.

7. We will keep close monitoring of the traffic condition of the three corridors, and when necessary, investigate suitable responding measures.

Transport Department March 2017