The best way to spread traffic evenly across the three harbour tunnels and ease congestion was for the government to own them, academics said yesterday - but the plan could cost about $11 billion. It would cost $5 billion to buy the Eastern Harbour Crossing and $6 billion for the Western Harbour Crossing, based on the remaining years of their contracts, said Lam Pun-lee, associate professor of accounting and finance at Polytechnic University. The figures do not account for more than $5 billion still owed on the western tunnel. If the purchases were made by issuing bonds, he said, toll income would not cover the interest on the bonds in the first few years. He suggested ownership of the three tunnels could be placed with a company owned by the government and shareholders of the eastern and western tunnels, allowing one entity to manage all three. The Cross-Harbour Tunnel is already owned by the government. But he said: 'I don't think the government should buy back the tunnels. If you wanted to privatise in the beginning, why are you buying them back now? This would be a discrepancy in policy.' Professor Lam's comments came after transport officials said they were studying the feasibility of buying the two private tunnels to ease traffic congestion at the Cross-Harbour Tunnel, which has the cheapest tolls. Congestion is expected to worsen when the Eastern Harbour Crossing's toll rises by 67 per cent to $25 per car on May 1, with officials estimating 3,800 more vehicles per day will use the Cross-Harbour Tunnel as a result. Hung Wing-tat, professor of civil engineering at Polytechnic University, agreed that buying the two privately owned tunnels was one of the best ways of solving congestion. 'Right now, the government is at a handicap because it does not have the rights to all three tunnels,' he said. 'The most effective method for traffic management is for the government to get control in setting the toll for the tunnels. Whether it would be in the form of an acquisition of the tunnels, taking some shares in the company or a joint operation is something that it needs to study.' Transport planning and safety specialist Wong Sze-chun, a professor at the University of Hong Kong, said traffic congestion was not just an aggravation for motorists but was reducing productivity for society as a whole. He said buying the two tunnels could solve the problem, adding that the government would probably want to increase the Cross-Harbour Tunnel toll after such a buyout, since its central location also helped make it the most popular.