World Car Free Day is coming in about a month's time. Since 1994, city dwellers in the world have been encouraged to abandon their gas-gulping cars for one day - on Sept 22 every year. Now the movement has spread to numerous cities across five continents, including Hong Kong, which had its first Car Free Day in September 2009.

The World Car Free Day aims to promote a more environmentally friendly transport patterns. Cars provide great mobility and convenience for city residents but the negative effects of excessive dependence on private cars for transport have become more apparent in metropolises, including Hong Kong. The first and worst negative impact from motor vehicles is air pollution caused by exhaust fumes. According to government statistics in 2015, among major air pollutants, 9 percent of respirable suspended particles, 10 percent of fine suspended particles, 18 percent of nitrogen oxides and volatile organic compounds, and a whopping 51 percent of carbon monoxide originated from road traffic.

Second, driving your own car can take you to your destination faster than public transport or bicycle under normal traffic conditions but too many cars on roads may cause congestion, dragging down general traffic efficiency and leading to much time wasted on the road. According to a report released by the government in 2014, the average speed of motor vehicles in Hong Kong was just 22.7 kilometers per hour. In some congested areas such as Central, the speed was less than 10 km/h. It can be inferred that huge amounts of time have been consumed by traffic congestion, leading to considerable economic losses.

And third, cars are also a major cause of traffic accidents and casualties. Hong Kong has one of the best traffic safety records among the world's mega cities but the number of casualties in traffic accidents every year is still significant. Last year 20,000 people were injured in traffic accidents, and 132 died.

Considering all the negative effects of car dependency, Hong Kong should do more to encourage people to drive less. Since 2009, Hong Kong has observed the World Car Free Day every year on a voluntary basis. Some car-owners answered the call and stopped using cars on the day, including several senior officials of the special administrative region government. However, due to its voluntary nature, the effects of the Car Free Day have not been very obvious. Based on my own observation, there was no significant drop in traffic flows on past Car Free Days, indicating that not too many car-owners stopped using their cars on that day.

Since Car Free Days based on voluntary basis were not very successful in lowering car usage, it may be time for the Hong Kong government to consider introducing compulsory measures to contain and decrease car usage, such as a compulsory Car Free Day.

The government may consider designating a Sunday every year, or even every month, as a compulsory Car Free Day, when only public transport vehicles - such as buses, minibuses and taxis - and cargo-transporting trucks and vans, and emergency vehicles, such as ambulances and fire engines, would be allowed to hit the roads. All cars, no matter whether privately or government-owned, would not be permitted on the road on the Car Free Day, or the drivers would face hefty fines.

During Car Free Day, the government may also designate a few thoroughfares in the city center as pedestrian-only roads. People can walk on these broad roads freely, instead of being confined to narrow sidewalks.

Since the compulsory Car Free Day would be set on a Sunday, when most people don't need to work, it would not cause too much trouble for commuters. The ones that must go out could still use public transport, which would be more efficient due to less congestion on the road. Maybe they would find the benefits of taking public transport and hence quit using their gas-hungry, road-occupying cars.

(HK Edition 08/21/2017 page8)