From roadway to \\\'road diet\\\'

Previously it was thought by transportation experts that the only solution to traffic congestions was to enhance roadway capacity by adding more lanes to the existing network apart from building new roads, flyovers and highways. However, judging by experiences in motorised vehicle-friendly cities like those in the US, transportation experts have realised that only increasing the roadway capacity is never a permanent solution to traffic congestions due to the ''induced demand'', which means an increase in capacity of the roadway will actually attract more traffic than anticipated. Because of the advantage of increased roadway capacity, new establishments are built along the roads. In addition, people, who were not previously travelling on such a road, may decide to take the advantage of the increased capacity of it. Furthermore, people, who did not drive before, may also consider driving on this road to take the advantage. As a result, more traffic will be generated on the road than anticipated, which will eventually clog the road resulting in traffic congestions.
Increasing the capacity of a roadway is a temporary fix. In the long run it makes the traffic situation even worse, because it attracts much more traffic than anticipated. Focusing on only the road infrastructure creates a vehicle-friendly city, which is not sustainable in the long run, as it creates traffic congestions, causes air pollution and eventually reduces the quality of living of the city residents.
Some cities across the world are now moving towards a 'road diet.' Under the road diet they are reducing the capacity of roadways for personal motorised vehicles by reducing the number of lanes for them and opening up those to non-motorised modes of transport such as walking and cycling. Some cities have even closed down their entire segments of roads for motorised transports and opened up those for walking and cycling. Such cities where planning is focused on non-motorised transports are known as people-friendly cities. Such cities have seen improvement in the living standard significantly as there is a less level of congestions and pollution due to a less volume of traffic. People get more time to spend with their families as they have to spend less time on commuting. City planning in our country should be focused on designing a 'people-friendly city' by building a network of sidewalks and bicycle lanes and providing mass transit
systems.
The writer, a transportation
engineer, works in Thailand.
 ridwanq@gmail.com