IF there is one thing nine-year-old Ng Way-yee wants it is a good night's sleep. 'I cannot concentrate on my studies during the day and I cannot sleep well at night because my room faces the highway,' she said staring out at the queues of traffic on Tai Po Road. Since the opening this month of the Lok Ma Chau border crossing, heavy trucks thunder past around-the-clock. 'It is noisier than before, especially at night,' Way-yee said. She is one of hundreds of people on Sheung Shui's Choi Yuen Estate living daily with noise levels which if recorded outside Hong Kong Stadium in Happy Valley would shut the place. While the stadium has a permitted limit of 65 decibels, the Government says people on the estate can live with 70 decibels. And residents will have to wait at least four years before they can get some peace and quiet. Transport consultants have warned the noise could get so bad that a concrete box costing $200 million would have to be built around the flyover next to the estate. For Way-yee, the incessant drone makes even simple things difficult. 'I have to turn up the volume of my television and speak up on the phone because of the noise in the background,' she said. Way-yee's mother said she thought the noise increased the stress on Way-yee and might damage her hearing. The Government's attempts to lessen the impact were useless, she said. 'The noise barriers do not work and I am still woken by heavy lorries as early as 5 am,' Mrs Ng said. 'Since the beginning of this month there have been more lorries during the night and it is really annoying,' she said. The couple living two floors above suffered from the same ordeal. Mr and Mrs Leung said they had developed insomnia because of the heavy night traffic. 'The noise wakes me every night at 2 am or 3 am. I am very disturbed and I can't sleep well,' said Leung Chan Hing-ling. 'I have lived here for more than 10 years and I am used to the noise from the traffic but still I cannot put up with the deafening sound from the lorries bumping along in the middle of the night,' Mrs Leung said. Since November 3 when the border opened to 24-hour traffic, the Choi Yuen Estate residents' committee has received more than 100 complaints from tenants living in Choi Wu, Choi Lai and Choi Wah House. District Board member So Sai-chi said they had never had so many complaints. A concrete box to contain the noise will not be in place until late 1998 at the earliest. The Highways Department said consultants had not recommended it and building it would be difficult. No decision would be made until the department received a report from a second firm of consultants - Maunsell Consultants - next summer. Tony Lam Lung-sung, technical director of Binnie Consultants, said his firm had carried out a preliminary assessment of noise from the trucks and recommended building the box as a long-term measure. As short-term measures, a low wall and a new road surface have been built on the flyover. But Mr Lam said the wall could have only a partial effect because it deflected noise upwards. 'The flyover is only a few metres away,' he said. Noise levels recorded by Maunsell Consultants, show an apparent worsening of the noise in both duration and intensity since the border opened to 24-hour traffic. On November 2, the eve of the opening, the highest level recorded was 70.2 decibels between 9 pm and 10 pm, marginally above the residential planning guideline of no sound higher than 70 decibels for more than six minutes in every hour. On November 8, the noise level had increased to a maximum of 72.5 decibels between 9 pm and 11 pm before falling below 70 decibels for the rest of the night. The Highways Department said noise levels were higher last year before the wall and new road surface were put in when a maximum of 74 decibels was recorded between 9 pm and 11 pm.