Makeovers for noisy flyovers

PUBLISHED : Saturday, 22 March, 2008, 12:00am
UPDATED : Saturday, 22 March, 2008, 12:00am

Researchers to test quieter road joints to reduce din in flats

Researchers aiming to reduce noise generated by traffic passing over worn-out road joints will conduct tests on several flyovers over the next year.

Noise levels at road joints can reach up to 90 decibels, which is as loud as noise generated by piledrivers at construction sites, according to previous studies, the Environmental Protection Department says.

The joints connect sections of roads and provide flexibility when they expand and contract as temperatures change.

The trials will be conducted by a research team led by Andrew Leung Yee-tak, from City University's building and construction department.

Costing about HK$1 million and funded by the government, the project will test five to six low- or no-noise joints on flyovers. All will be developed and supplied free by manufacturers. Some manufacturers claim their designs are noise-free.

While researchers have yet to make a final decision, they are likely to choose noise pollution black spots like the Eastern Corridor section near City Garden and the Mei Foo Sun Chuen section of Lai Chi Kok Bridge for the tests.

'Unlike the background traffic noise that is rather monotonous and continuous, this road-joint noise is rather sharp and short. But it is still very annoying,' Professor Leung said.

Researchers said most joints had a 2mm to 3mm height difference. But worn-out joints were unaligned and generated louder noise as vehicles crossed them.

'In the past, there was no specification on acceptable noise levels from road-joint design and there is no world standard,' Professor Leung said.

Hui Ching-on, an Eastern District councillor, said more than 100 complaints had been received over the past eight years from residents of City Garden flats which are within 50 metres of the busy Island Eastern Corridor.

He said traffic noise from the joints could reach up to 90 decibels and seriously disturb residents' sleep.

'Some residents move in and out quickly as they find the noise level intolerable,' he said.

It was estimated in 2006 that about 1 million people in Hong Kong are exposed to excessive traffic noise above 70 decibels. And while noise barriers have become standard in designs for new roads, many residents living near roads still suffer.

To cut the noise, the government decided to resurface 72 sections of road by 2010 with low-noise materials. So far, 36 have been completed and work on 12 is under way. Feasibility studies on 14 sections are being carried out.

Last year, complaints about construction and neighbourhood noise fell to 7,970, from 8,755 in 2006, according to the Environmental Protection Department.