The 5.9km Route 8 Cheung Sha Wan to Sha Tin section will open to traffic at the end of March, cutting journey time between Sha Tin and Tsim Sha Tsui by 15 minutes.

Highways Department Major Works Project Management Office Chief Engineer Michael Hui told news.gov.hk the new dual three-lane road will be Hong Kong's fourth link between Sha Tin and Kowloon, comprising the Eagle's Nest and Sha Tin Heights Tunnels and the Lai Chi Kok Viaduct. Click here to tour the new link.

New link: Highways Department Chief Engineer Michael Hui says the Route 8 toll plaza offers 18 tollbooths while flowering plants will be grown along Lai Chi Kok Viaduct to green the city.

More capacity

The existing three links - the Lion Rock and Tate's Cairn Tunnels and Tai Po Road - are always congested. January saw 2.82 million cars use the Lion Rock Tunnel and 1.77 million use the Tate's Cairn Tunnel, up 8,500 and 60,900 vehicles on the same month last year.

Mr Hui said: "The new link, costing $5 billion, can cater up to 120,000 vehicles a day. As the Tsing Sha Control Area will, same as the Lion Rock Tunnel, adopt a flat rate of $8 for all vehicles, the new link can help divert traffic from the existing ones and improve traffic flow."

To cater for traffic growth brought by the new link, Road T3 will open at the same time while roads in Tai Wai have been upgraded to avoid traffic jams.

Works on the 1km Sha Tin Heights Tunnel started in November 2002. It comprises twin horseshoe shaped tubes of about 16m in width and 9m in height, with approaches linking Road T3 and Che Kung Miu Road.

In October 2003 the department started building the 2.1km Eagle's Nest Tunnel comprising twin horseshoe shaped tubes measuring 15m wide and 10m high. It is the longest dual three-lane government tunnel.

Between these two tunnels is a toll plaza with 18 tollbooths and an administration building. Bus lay-bys of 100m in length on each side of the plaza have been built for bus interchange.

For the 1.4km Lai Chi Kok Viaduct works started in September 2003. Its bridge deck rises up to 45m from ground level and the span length varies from 45m to 80m.

Extensive greening

Mr Hui said both tunnels, with a speed limit of 80kph, are equipped with ventilation, lighting, and traffic control and surveillance facilities. Cross passages between tunnel tubes at 100m intervals are provided for emergency evacuation to the adjacent tube.

"Apart from closed-circuit televisions and smoke detectors, we have also installed for the first time linear heat detectors throughout the tunnels as one of the fire protection facilities," he added.

Planting works have been conducted along the route, including 1,550 trees, 70,000 whip trees and 375,000 shrubs.

The roof of the noise enclosure on the Sha Tin Heights Tunnel approach serves as a landscaped deck with extensive planting while climbers will be planted at noise barriers in Butterfly Valley to make them blend with surroundings. An earth mound - a recycled plastic structure filled with soil for growing plants to cut noise - has been built near the administration building at the toll plaza.

Mr Hui said: "Planters have been built along some sections of the Lai Chi Kok Viaduct for growing flowering plants, such as yellow ixora, lantana camara, chulan tree and azalea to green the link. We have also upgraded the stream in Butterfly Valley making it more appealing to birds and fish."

Waste recycling

The new route passes underneath Kowloon Reservoir and water pipes there posed challenges to engineers.

Mr Hui said: "There were many water pipes near Eagle's Nest Tunnel, with the nearest one just 10m away from the tunnel. Good tunnelling techniques and close monitoring were key to ensuring the pipes were not affected by the tunnel construction."

It took construction workers 30 months to break through the two tunnels resulting in one million tonnes of excavated rocks.

"To avoid adding pressure on public landfills, all the excavated rocks have been recycled with those of better quality sent to Tsing Yi for making concrete while others will be used as fill materials in works projects," he said.

The construction of Lai Chi Kok Viaduct was also not an easy task as it runs via the busy West Kowloon Highway, Lai Chi Kok Road, Cheung Sha Wan Road, Castle Peak Road and Ching Cheung Road where many utility pipes are underground.

Mr Hui said: "To keep people and traffic moving without affecting underground facilities a well-thought-out plan and state-of-the-art construction techniques helped us achieve the target.

"The viaduct was designed with long spans and the bridge deck built with pre-cast segments to cut traffic disruption. We installed the segments at night with full compliance with environmental noise controls."

Layered structure

He said Lai Chi Kok Viaduct joins Ngong Shuen Chau Viaduct at Lai Wan Interchange forming a five-layered highway structure, the most complicated one in the city.

The structure comprises Lin Cheung Road as the first layer, a road overpassing it is the second, West Kowloon Highway is the third, the new ramp from Ngong Shuen Chau Viaduct to West Kowloon Highway is the fourth, and the new mainline from Lai Chi Kok Viaduct to Ngong Shuen Chau Viaduct is the fifth.

For the Route 8 Tsing Yi to Cheung Sha Wan section Mr Hui said 70% of the works on Stonecutters Bridge have been completed.

"The bridge towers will be 298m high. The East Tower now reaches 273m and the West Tower 230m, both higher than the Tsing Ma Bridge towers," he added.

For more details on Route 8 click here.