Traffic flow at the three harbour tunnels was down 9 per cent on usual numbers yesterday afternoon, with virtually no sign of traffic congestion caused by the fare rise at the Easter Harbour Tunnel. There was little traffic congestion at the Cross-Harbour Tunnel even during evening rush hour, transport officials said. Traffic flow was down 2 per cent at the Cross-Harbour Tunnel and 3 per cent at the Western Harbour Tunnel. The Eastern Harbour Tunnel, which raised its toll on Sunday, recorded a drop of 23 per cent in vehicles. A Transport Department spokesman said emergency transport co-ordination would continue, adding that traffic was expected to get heavier next week when trucks returned to the roads following the May Day 'golden week' holiday on the mainland. Three students taking the Hong Kong Certificate of Education Examination had to be redirected to different examination centres yesterday morning after being trapped in traffic jams on the way to test centres. They did not have to travel across the harbour for the exams, but encountered congestion in their own district. Under the government's traffic contingency plan, the Hong Kong Examination and Assessment Authority arranged for the students to sit the test at different centres. 'Our priority is to ensure that the students are able to take the exam,' an authority spokeswoman said. 'We don't want to give the impression that anyone can change their test centre anytime. These students have to provide us with written proof later about their special circumstances.' Yesterday was the first time since Tuesday that the authority received calls on its hotline from students requiring assistance in getting to their exam centre.