Cars, cars, and more cars--that seems to be the trend in most growing cities in the world. The direct outcome of this is that people spend many unproductive hours stuck in traffic jams. But the more long-term outcome is that traffic jams are harming the economy of many cities like Lagos, Manila, and Sao Paulo.

One of the main reasons for the rising number of drivers on the roads and traffic jams is the increasing affluence of urban populations. However, government policies are also to blame. While some countries have subsidized fuel prices, others have forced builders to provide large parking spaces in their new projects. On the other hand, some cities like Beijing, Delhi, and Mexico City have tried to reduce traffic (and pollution) by introducing an odd-even formula. But this has only encouraged many families to buy a second car so that they have cars with number plates ending in both odd and even numbers.

The way forward seems to be in building effective public transport systems such as rapid bus networks, and in doing away with fuel subsidies and minimum parking lot requirements.