The Anak Bukit Flyover in Bukit Timah will be the first road in Singapore to get permanent noise barriers.
Construction of the barriers - measuring 6m in height and 225m in length - began yesterday and will be completed in October, bringing some relief to nearby residents who have complained about noise pollution.
The Land Transport Authority (LTA) said yesterday that this is part of a trial to assess the effectiveness of such barriers in reducing traffic noise.
It will also finish installing similar structures along the West Coast Highway near Block 44, Telok Blangah Drive, by the middle of next year.
The new flyover being built along Braddell Road near Block 138, Bishan Street 12, will also get the barriers some time in 2016.
These three locations were selected based on their high traffic volumes and noise levels, explained the LTA yesterday.
The barriers will cost about $3.8 million in total, a spokesman added.
Jurong GRC MP Halimah Yacob had raised the issue of noise in the Anak Bukit Flyover's vicinity as early as 2012, when residents voiced concerns over the widening of the road - part of the recent expansion of the Pan-Island Expressway.
"As the carriageways will come closer to the adjacent (condominium) Sherwood Towers... I asked the LTA whether they could put up noise barriers," Madam Halimah told The Straits Times.
"I was really very glad when they accepted the idea... given our very compact environment where living spaces jostle side by side with busy roads, I would think that this would be a necessary feature to mitigate noise and provide a better living environment."
The barriers are made of a combination of transparent and absorptive panels. The latter are lined internally with rock wool, a material commonly used to absorb sound.
Sherwood Towers residents whom The Straits Time spoke to yesterday said noise had been a long-time problem, and that it often gets "quite noisy" at night.
Mr Liu San, a 49-year-old chef at a restaurant in Bukit Timah Plaza beside the condominium, has been living at Sherwood Towers for more than 20 years.
"If they really help to reduce the noise, that will be good," he said of the barriers. "I've seen similar sound walls in European countries."
Others said they were fed up waiting for a solution, while some were resigned to having to live with noise, even after the barriers come up.
Retiree Chan Heng Wah, 72, who has lived in the area for four years, said: "We are surrounded by traffic on all four sides. There is no way to block all the noise."
The LTA said it would monitor how well the barriers work before considering a "targeted islandwide implementation programme".
Additional reporting by Marissa Lee