Finishing touches are being applied on the Marina Coastal Expressway (MCE), which is on track to open by the end of this year.
All structural works have been completed on the 5km, $4.3 billion highway, including a 420m undersea tunnel.
The bulk of electrical and mechanical systems has been installed and contractors have begun testing and commissioning those systems, a process that will take about five months.
This update on Singapore's 10th expressway was given by Transport Minister Lui Tuck Yew after he visited the MCE control centre yesterday. It will be a key link connecting expressways in the east and west, he said.
"The MCE will offer commuters a direct and high-capacity link to the new downtown at Marina Bay, and is therefore a critical development that supports Singapore's growth as a financial hub."
It will connect East Coast Parkway (ECP) and the Kallang-Paya Lebar Expressway (KPE) with the Ayer Rajah Expressway (AYE).
With five lanes each way, it can carry 10,000 vehicles an hour in each direction and replace the ECP as the main route for motorists travelling across the various expressways. Designed with a top speed of 80kmh, the MCE will link to the KPE, which has a maximum speed of 70kmh.
The Land Transport Authority (LTA) said it is assessing whether to raise the KPE speed limit to match that of the MCE.
After the MCE opens, a portion of the ECP after Benjamin Sheares Bridge will be downgraded to an arterial road, with traffic lights and crossings, that connects to the Central Business District (CBD).
Currently, the Marina area is split in half by the ECP. The downgraded portion of the ECP will be named Sheares Avenue.
The LTA will readjust several Electronic Road Pricing (ERP) gantries to cover the new road connections created by the MCE.
Gantries currently on the to-be-downgraded part of ECP, like the one in Ophir Road, will be removed and replacements installed on the MCE.
Motorists will continue to pay the existing ERP charges when they use the MCE or ECP to enter the CBD. For instance, it costs between 50 cents and $5 now to pass through the gantry on the ECP after Fort Road from 7.30am to 9.30am on weekdays.
Mr Lui noted the challenging engineering obstacles posed by the MCE. "Since much of the MCE is built on reclaimed land, engineers had to contend with soil condition that, I am told, is almost like peanut butter."
Some 13.1ha of land was reclaimed for the project and the largely soft clay ground had to be improved to stabilise it.
Deep and wide excavations posed another challenge.
The average excavation width was 60m, wide enough for more than 15 traffic lanes, while tunnels went as deep as 25m - the equivalent of an eight-storey building.
In all, 4.3 million cubic m of soil was excavated, about half a kilometre of earth stacked on a football field.
The MCE will have a total of nine entry and exit points to the ECP, Marina Boulevard, Central Boulevard and Maxwell Road. There are provisions for another five access points in Marina East.