A global study's conclusion that Hong Kong has the "most advanced urban mobility system in the world" comes as no surprise to visitors and residents who have lived overseas. They are bedazzled by trains and buses that leave every few minutes and routes that cover even the remotest village. But while we can be proud that we have topped the 84-city list, it would be a mistake to rest on our laurels. A relentless annual rise in the number of vehicles and high levels of transport-related air pollution threaten our ranking as well as efficiency. The report by international consultancy firm Arthur D. Little highlights the MTR, Octopus card system and low car usage among factors making Hong Kong a public mobility leader. Praising the first two is understandable: few railways are as easy to use, inexpensive, dependable and clean as the MTR, while the Octopus system has revolutionised the way we pay fares and bills. The government's policy of encouraging public transport use through high fees and taxes for private vehicle ownership has kept numbers low, but the approach is no longer effective. Thousands of new cars are taking to the roads each year, worsening the gridlock and slowing buses and taxis. A relentless tide of tourists from the mainland is straining MTR services. Roadside levels of nitrogen dioxide and small particulates from old diesel buses and trucks remain unacceptably high and have been increasing. The study also faulted the low number of bicycle paths and facilities, citing the transportation mode as being good for health and cutting air pollution. Bicycles are generally not on the authorities' public transport radar, though; beyond a few parts of the New Territories they are seen as being worthy only for leisure. A better co-ordinated overall transport strategy would improve efficiency. Reducing traffic congestion through road pricing should be considered; getting polluting vehicles off roads is essential. As in other cities, bicycles should be seen as a transportation mode. Topping a world ranking is good for egos, but more important is ensuring that what we have works well.