Limit private cars that are occupying too many Hong Kong roads

The top challenge for Chief Executive Leung Chun-ying in his 2015 policy address is to tackle Hong Kong's congested roads.

They have been occupied by all sorts of vehicles, but it is private cars that are as serious a problem as Occupy Central in slowing traffic to a crawl during rush hours and also at other times in certain districts. This is choking us with toxic fumes.

As a priority, the government must review which types of vehicles should have priority on our roads, especially at rush hours and in congested areas.

The Environmental Protection Department has indicated that slow vehicle movement, probably due to congestion, emits more airborne pollutants such as nitrogen oxides (NOx) and tiny particles, called particulate matter (PM), that are harmful to public health. Professor Anthony Hedley of the University of Hong Kong, an environmental health expert, has warned that children are most at risk from damage to their lung development.

The department's figures show that a double-decker bus travelling at 8km/h emits on average 39.5g/km of NOx and 0.57g/km of PM10 - particle pollution less than 10 micrometres in diameter. But if the same bus travels at 40km/h, it emits only 16.7g/km of NOx and 0.2g/km of PM10. So a bus travelling slowly during rush hour would emit 136 per cent more NOx and 185 per cent more PM10.

Statistics from the Transport Department last year reveal that, on average, private cars accounted for 53.8 per cent of the vehicles using the three cross-harbour tunnels from Monday to Friday during the rush hour - 8am-9am and 6pm-7pm. But franchised buses accounted for only 5.3 per cent of vehicles, showing that private cars are the main culprit when it comes to slowing traffic along the city's main corridors.