SINGAPORE - More than 20 years after it was first announced, Singapore's plans for a 30km underground road network have been scrapped.

"As Singapore shifts towards a car-lite society, land previously safeguarded for the Singapore Underground Road System (SURS) will be de-safeguarded with effect from today," the Land Transport Authority and Urban Redevelopment Authority said in a surprise joint statement on Tuesday (Aug 29).

The underground road network was conceptualised in the late-1980s as an underground arterial ring road system around the fringe of the city, to cater to potential traffic growth into and out of the city centre. Land along the SURS alignment was safeguarded in 1993.

"Enhancements to our public transport network and changes in land use policies have removed the need for SURS," the joint statement added. "The city centre is well-served by a comprehensive public transport network and the full opening of the Downtown Line on Oct 21 this year will further improve public transport connectivity, especially for commuters travelling from the north-western and eastern regions of the island to the Central Business District and Marina Bay areas."

With the underground road network no longer needed, land which had been safeguarded for it can now be redeveloped. Previously affected land owners will now have greater flexibility in their development plans, according to the two government agencies.

The underground road network was previously seen as a way for Singapore to move traffic underground so as to preserve more surface space for other uses. The Marina Coastal Expressway was one example of how the government had moved traffic below ground so as to free up a large parcel of prime land for redevelopment.

As recently as 2013, the LTA said in its masterplan that it was studying a plan to link the CBD, Marina Bay Downtown and the future southern waterfront district by an extensive underground road network to be built after 2030. Various cities such as Brussels, Stockholm, Madrid and Paris have factored in such roads in their city plans.