A toll increase for trucks has been suggested as a possible solution to the serious congestion that plagues the Cross-Harbour Tunnel. The idea is that this would encourage many such vehicles to use the two other under-used but more expensive crossings. It is no more than a proposal, prompted by a consultant's study of cross-harbour traffic flows for the government, which found that heavy vehicles cause disproportionate wear and tear to the tunnel but pay only HK$10 more than cars. But it prompted a threat of chaos from a spokesman for truck drivers, who said that if they had to pay higher tolls they would blockade traffic and even lie down on the roads in protest.

Given the government's lack of political will to act on the long-standing problem of tunnel congestion, we need not hold our breath waiting for such a confrontation. We have known for years that the solution is to adjust tolls to spread traffic more evenly between the government-owned Cross-Harbour Tunnel and the privately operated eastern and western crossings. But officials do not appear to have the stomach for the inevitable protests by users of the cheaper tunnel. Indeed, one official reminded us this week that an across-the-board increase for Cross-Harbour Tunnel users remains politically impossible. We should not have to wait until 2016 when the build, operate and transfer agreement sees the private operator hand the eastern tunnel over to the government, giving it control over two of the three tunnels. Given the government's preference for ruling by consensus, there is no guarantee that it will seize the opportunity to rationalise tolls. And if it is left to the chief executive to be elected in 2017 - presumably by universal suffrage - it remains to be seen if a popular mandate will lead to more decisive governance.

Many options for evening out tunnel traffic have been floated but found impracticable for various reasons. Meanwhile, vehicles queue at the Cross-Harbour Tunnel entrances, engines idling, wasting time and adding to pollution, as we reclaim more land to build more roads. The government needs to take the initiative now and adjust the tunnel's tolls - and not by just hitting heavy trucks.