I don't think this trend will continue in the future. It means that if only one person uses a motorcycle, the number of motorcycle trips will increase. Then the shift to car usage will be accelerated, which will create more congestion. Then as urban area grows, average trip length will increase; people will have to spend more time to go to the destination.
So what will likely be the average level of the traffic demand in the future? Now, the number of person's trip/day is 8.3 million in 1996, and it is estimated in one study to grow to 22 million (2.6 times) in 20 years' time. But if you convert this person's trip to PCU trips, it will increase much more than the person's trip. It means the actual congestion on roads will be worsening faster than the traffic demand itself. If traffic demand is triple, technically we will have to construct 3 times larger roads, additionally, but it is impossible.
Under such situation, we can first discuss the general transport development strategy for HCMC. HCMC area can be broadly categorized: one is the city center area, and the second is the corridor area, and the third is suburban area. For each of these areas, we have to think how we are going to develop roads, how we are going to manage the traffic, what the directions of public transport development are and integrated development with the transport and land use.
For the CBD, it is very difficult to expand and provide more roads. So all what we can do is to make a minor improvement and also to construct the missing links. But for the corridor areas, we should consider widening and constructing distributors. In suburban areas, we need more network development of the road.
But for the traffic management, we need a more vigorous traffic management for the CBD areas, like parking control or demand management. We have to constrain people from using their vehicles freely in the CBD. However, for the corridors, we can prioritize the traffic and define what type of traffic will be given priority. And also we have to control roadside activities. Capacity of many of roads has reduced because of the uncontrolled roadside activities. And in suburban area, separation from the through traffic is needed. There are many inter-city traffic flows, which also sometimes destroy the environment in the suburban areas. So how can we separate the through traffic from the local traffic?
With regard to public transport development, this is the key for the transport planning. Public transport development is important in the CBD, corridor and suburban areas. But the way we are going to approach is different. For the CBD, we need a mass transit, either elevated, underground, because the space for railway construction is very limited. Since the traffic demand within the CBD involves with variety of demands, so we have to provide various transport modes. However, for the CBD, we are looking into efficiency, so we need mass transit, including MRT, bus way and so on. And also we should provide alternative modes like buses. But in suburban areas where transport infrastructure and facilities are not provided well, we have to ensure good access to key public transport routes, and provide good local area services.
