THE construction of the urban section of Route 3 in Kwai Chung will start this month, sparking fears that it will bring serious congestion to the already-busy Kwai Chung Road and Container Port Road. United Democrat legislator Lee Wing-tat said yesterday after meeting Highways Department engineers that there would be major traffic diversions in Kwai Chung when work started. He said the department promised the number of lanes would not be reduced but he was worried because the lanes would be narrowed to allow space for building buttresses for Route 3. ''There are normally big container trucks using the roads in Kwai Chung. If the lanes are narrowed, the drivers still need to slow down to avoid hitting vehicles on the next lane, and that would be a potential cause of serious traffic jams,'' he said. Mr Lee said the Highways Department promised to assign 50 officers and the contractors would have 150 on-site engineers to monitor traffic conditions. The construction work is expected to last two years and traffic diversions will affect parts of Container Port Road, Kwai Tai Road and Kwai King Road, the area of Terminals 1, 2, 3 and 5. Mr Lee said he expected traffic in Kwai Chung to be very congested early next year when all four parts of the project would be underway. He said he would meet Transport Department officials next week to discuss ways to minimise the impact on Kwai Tsing traffic.