Not feasible to have full-tunnel North-South Expressway

Royston Sim Straits Times 15 Feb 11;

SEMI-TUNNEL sections of the planned North-South Expressway (NSE) will not be converted to closed tunnels.

Transport Minister Raymond Lim told Parliament this was not feasible, because of the lack of land sites needed for ventilation buildings above such tunnels.

The NSE will have two semi-tunnel sections: between the Seletar Expressway (SLE) and south of Ang Mo Kio Avenue 9; and between Sin Ming Avenue and north of Pemimpin Place.

Ms Lee Bee Wah (Ang Mo Kio GRC), citing feedback from affected residents in her Nee Soon South ward, asked Mr Lim if semi-tunnels close to residential areas could be converted to full tunnels.

He said that while the Land Transport Authority (LTA) has tried to plan for the NSE to be a full tunnel in highly urbanised areas, this was not always possible.

For the semi-tunnel stretches to be full tunnels, more land would be needed for ventilation buildings. These would occupy an area of 15,000 sq m each - the size of nearly 21/2 football fields - and must be built close to the tunnel at intervals.

According to LTA data, six such buildings would be needed if the whole NSE section south of the SLE became a tunnel. But owing to competing land uses, the LTA could identify only five suitable sites.

Mr Lim said possible land sites such as the undeveloped land around Lentor Avenue and Yio Chu Kang Road were either obstructed by the existing MRT viaduct, part of the Defence Ministry's training ground, or close to the Yio Chu Kang MRT station, where land has been reserved for residential use.

A ventilation building in the vicinity of Bishan Park would also be required, but this would affect national water agency PUB's Active, Beautiful and Clean Waters upgrading programme there, he added.

Construction on the NSE is expected to start in two years. The project, which will cost between $7billion and $8 billion, will link northern Singapore to the city, and is expected to be ready by 2020.

The 15.9km northern segment from Admiralty Road West to Toa Payoh Rise was announced on Jan19. It will have the longest viaduct in Singapore, as well as surface roads, semi-tunnels and tunnels.

The NSE is expected to reduce travel time to the city by up to 30 per cent after its opening, and ease congestion on major roads in the north-south corridor, such as the Central Expressway and Thomson Road.

Mr Lim also assured Ms Lee that the LTA would ensure the NSE meets National Environment Agency standards for road traffic noise when it is in operation. The LTA has considerable experience in building major roads close to residential areas, he added.

The minister said the LTA is conducting engineering studies on noise mitigation, and "will try to complete it as soon as possible". Possible measures such as dense planting, using porous asphalt on the roads to reduce traffic noise and shaped screens will be implemented where necessary.

The LTA could also consider how best to construct the project in phases so as to minimise inconvenience to residents, Mr Lim said.

North-South Expressway may be built in stages to minimise disruption and noise to residents
Hoe Yeen Nie Today Online 14 Feb 11;

SINGAPORE-The Land Transport Authority (LTA) has said it will consider building the North-South Expressway in phases, where feasible. This comes after MP for Ang Mo Kio GRC Lee Bee Wah suggested in Parliament that portions closest to residential areas be completed first, with the aim of minimising disruption to residents over what is estimated to be a seven-year project.

Another issue was whether parts of the expressway near homes could be built as full tunnels, to ease traffic and noise disruption after the expressway is completed.

Transport Minister Raymond Lim replied that while the expressway was designed as a full tunnel in highly urbanised areas, this was not always possible because large plots of land about 15,000 square metres, or about two football fields, are needed for the required ventilation buildings.

Besides having to compete with other land uses, Mr Lim said there are also limits to how far possible sites, like the undeveloped land around Lentor Avenue and Yio Chu Kang road, can be developed.

HO YEEN NIE