As traffic congestion continues growing in urban areas, more and more cities have realized that investment priority should be given to public transport modes, such as metro trains, bus rapid transit systems (BRT) or buses, instead of personal vehicles. Simply put, public transport modes are more efficient than personal vehicles in terms of carrying and moving people around. However, international experiences also tell us that building more metro lines or putting more buses on the road alone may not be able to get more people to use public transport modes.
There are several non-transport factors, or urban design factors, that play a critical role in a traveler’s decision on their best travel mode.
The first critical factor is density. As illustrated in a famous study done by Alain Bertaud, a former World Bank staff, density is the primary reason why 30 percent of daily trips are carried out by public transport in Barcelona, but only four percent in Atlanta. Barcelona is about 30 times denser than Atlanta, so it is therefore much easier to provide same level of public transport services in Barcelona than Atlanta.
One lesser-known factor is accessibility. Just having a high population density may not guarantee more people to use public transport.