Congestion creates long waiting lines at most major intersections resulting in enormously long and unpredictable travel time and congestion spots.
1. Bangkok Urban Transportation Problems
Transportation problems in many major urban areas tend to show some similarity depending upon travel pattern for the city. Bangkok, one of the fastest growing cities in Southeast Asia exhibits similar problems as other major cities in development world. The main problems seem to be congestion and accident. Others included poor public transportation systems, lack of facilities maintenance, high transport costs for low income population group, etc. However, Bangkok transport problems exhibit some special characteristics as follows.
Congestion creates long waiting lines at most major intersections resulting in enormously long and unpredictable travel time and congestion spots.
Congestion in the inner core area is normally increased from early morning until late afternoon on to evening almost on every weekday.
Bus patronage suffer hot humid weather and crowded vehicles and therefore were perceived as a very low level of service mode and the city lack of appropriate mass transit system.
High accident involvement due to rushing through the red light and aggressive driving behavior resulting in great loss and even higher congestion.
Coarse road network with numerous missing links of distributor and some main roads.
Poor land use control especially along minor and distributor roads.
High level of suspended particulate and carbon monoxide affecting from traffic congestion.
Coarse road network with numerous missing links and lack of proper minor and distributor (collector) road systems.
Poor land use control especially along minor and distributor roads.
High level of air pollution especially suspended particulate and carbon monoxide and noise pollution especially along the main truck routes despite strong regulations and enforcement.
The problems are considered to be part of rapidly growing urban area where the pace of economics growth was much faster than the pace of infrastructure development by the government. Public transport especially bus system has been receiving much less attention. The high economic growth consequently created high family income and high vehicle ownership. Therefore most of the infrastructure development were directed oriented toward private vehicle usage. This situation went on to create further congestion and impacted on bus services since buses used the same right of way with private car. The situation became worse when the buses and other public transport systems could not maintain proper level of services. Therefore, most of the commuters tried to own and use private vehicles for almost all trips resulting in more private vehicles on the road network and consequently more congestion.
2. 2. The Proposed Transportation Strategies.
Most of the recent transport studies which employed problem oriented study approach recommended normal transportation strategies to tackle congestion problems as follows.
From the recommended strategies, It is clear that increasing supply for private vehicles (more roads) will not alleviate congestion problems. More road spaces seem to induce more private cars on to the network (since benefits gained from using private cars is higher than other modes) resulting in higher congestion. Therefore, the high prioritized strategy was on improvement and development of public transportation systems.
It is believed that if the mass transit system is constructed, the main group of patronage will be the former public transport users since the new alternatives provide higher benefits. The second patronage group will be a group of commuters formerly did not make trip because of high congestion (latent demand group). Then the third group will be the former private car users. Therefore, there is likely to be a considerable excess of demand over supply of road space and the transit systems. Thus most problems will still exist and may be worse because of less development alternative. It is believed that one of the very important alternatives to tackle long term problems is to introduce some traffic restrained schemes in a near futures to supplement other improvement and development alternatives so that less benefit of using private modes incur over the public transport modes. This is the starting point of this project.
3. Traffic Restraint Schemes.
Traffic restrained schemes have been introduced and discussed, on many occasions, in Bangkok for more than 5 years. There were at least three government agencies discussed and carried out review studies related to the topic. The discussions are summarized below.
OCMRT (during the period that the agency was attached to the Ministry of Interior) initiated discussion on possibility of introducing various traffic restrained schemes such as banned trucks and odd-even number plate vehicles for different days in the central area.
BMA through a team of consultants assigned by JICA carried out a study related to traffic improvement programs for Bangkok and recommended selected restrained schemes such as parking control in inner area.
Police Department (PD) specially Traffic Police Division has looked into and introduced a number of controls imposed on truck movement in certain area.
NESDB during the study to prepare the Sixth National Plan through a team of consultants performed a comprehensive review of transportation investment packages for Bangkok and part of the study results suggested a traffic pricing scheme in the central area of Bangkok.
In 1992 The Engineering Institute of Thailand (EIT) by the transportation subcommittee carried out an in-depth review of the traffic restrained measures and published the results in the EIT journal (in Thai). The article produced thorough understanding of the schemes.
In conclusion, traffic restrained schemes are a group of projects when implemented would result in changing of 4 main travel characteristics: mode of travel, travel route, destination, and time of travel with the main objectives to alleviate traffic congestion and improvement of environmental quality. Table 1 summarized the projects.
4. The Suitable Traffic Condition.
The study area for the project is the Greater Bangkok Area (GBA) which covered 4 main provinces: Bangkok, Samut Prakarn, Nonthaburi, and Prathumthani. The area was subdivided into 6 main groups for detail study of traffic condition. The main division was further subdivided into 118 traffic zones and 4 other outside zones covered part of the central region. Table 2 and 3 showed existing travel pattern and traffic condition of the study area. The results indicated that peak hour congestion occurred most within subarea 1-4. Average speed was as low as 9-10 km/hr and speed variation is more than 60% of the mean. Table 2 also indicated enormously high utilization of private cars within these subareas. Table 4 showed a suitable traffic condition for GBA. The condition was derived after reducing the use of private car trip interchanges in different subarea according to family income and its distribution. Results of the study indicated the following conclusions.
Remarks
1. Before this study, the author had performed few studies related to analyze traffic conditions in Bangkok. Some studies related traffic conditions with air pollution; some related travel speed with congestion by vehicle types and locations. Therefore, the main assumption for this study is travel speed. It is believed that in order to alleviate congestion problems in Bangkok, travel speed for all vehicle types specially bus was the main measure and criteria was set up such that the average travel speed of bus patron was about 20-25 km./hr.
2. The existing traffic conditions and the derived suitable traffic conditions were carried out through modeling effort. The pcu-trip matrix for the peak hour was derived from combining four vehicle types peak hour trip matrices (private cars, motor cycle, bus, and taxi including samlor) together. Each vehicle type matrix was estimated from using matrix estimation model with the available 24-hr matrix and peak hour volume count. The resulting pcu peak hour matrix was then assigned onto the network and the forecast volume were compared with the screenline volume. The results were with in 20% range.
3. The suitable traffic condition were derived by going back to the private car matrix and reduced amount of trip interchanges between traffic zones followed family income pattern. The reduction was done until the average travel speed in each subdivision resulted from traffic assignment was achieved.
5. Preliminary Schemes.
Preliminary schemes are mainly related to improvement of existing public transport system and level of services. Results of the analysis of existing trip characteristics were shown in Table 5. The major improvement should be made on, first, the use of private cars for school- trip purpose. The school-trip purpose is about 18.5% of the total trips. Most of them were made by either walking or using public bus. However, about 25% were made by using private car. This amount of unnecessary private car trips was made during peak hour and formed part of the congestion on the road network. Therefore, the most urgent project is the implementation of school bus for selected schools. School bus should be improved such that about half of the private car trips for this purpose transfer to use school bus. Results of the former study related to school bus suggested the main level of services that must be improved including: safety, excess travel time of the first group of students on the bus and comfortable. The service should be rearranged such that each bus pick up students (of 3-4 schools) who live close together and dropped at a group of schools located close together. Next step is the improvement of existing bus transport. According to the analysis of mode choice models, there were three main and two minor characteristics required improvement. The improvement would certainly effect commuters' decision and will lead to mode changed. Those characteristics are travel speed, total time spent before using the trunk route/s, number of transfers, transfer time, reliability and comfort. The analysis of the choice models provided the following conclusions.
6. Traffic Restraint Schemes
Even the proposed changes to public transport and school buses, there would still be a need to further reduce demand and increase mode changed. From the analysis of existing traffic condition, suitable traffic condition, and amount of private car trip interchanges including the choice models, it was concluded that there were two traffic restrained schmes suitable for GBA : Odd-Even Number Plate, and Area Pricing or Licensing schemes. Since these schemes would effect another 20% of private car users to reconsider use the private cars.
It was found that the Odd-Even Number Plate method is quite effective in Seoul, South Korea during the 1992 Olympic Game. Total private car trips during peak hour were reduced by about 30-35%. If this method is implemented in GBA, it was assumed that the result would be the same. Therefore the future traffic condition would be close to the suitable condition.
For the study of Area Pricing or Licensing scheme, the analysis steps were as follows.
7. Detail of the Schemes.
7.1 Preliminary Schemes
The preliminary schemes emphasized on improvement of public bus transport to be an alternative travel mode for most commuters in Bangkok. From the analysis of the mode choice and level of service assumptions, the following improvements were recommended.
The improvement of all bus services will also include priority of bus flow at junctions and improvement of physical condition for pedestrian movement at bus stops or at terminals and interchanges. These improvements will form a comprehensive public transport improvement packages, since they will fit together to provide a system with much better level of services suitable to most commuters in Bangkok. Also the system is flexible enough to rearrange to be feeders of the rail mass transit when it is implemented.
7.2 Traffic Restraint Measures.
There were two schemes recommended: Odd-Even Number Plate and Area Pricing or Licensing. The evaluation of each scheme was carried out by studying 6 main characteristics: simplicity effectiveness, flexibility, alternative of movement, impact, and activities related to the implementation of the project. After thoroughly review and discussed with OCMRT, it was concluded that the Area Pricing Scheme is more suitable to the situation in GBA than the other method. This is because of the three main reasons: effectiveness, flexibility, and alternate travel mode. The system cannot be said to favor the rich since every car must pay for the charge. Other main reasons included low short-range impact, possibility of introduction of land use control to manage long range impact, and simple and manageable activities.
8. Economic Evaluation
Economic evaluations were carried for two main cases: considering just an investment of the Area Pricing Scheme, and considering investment of the whole improvement programs. For the first case, it is assumed that other improvements except the restraint project would gain their own benefits, while for the second case, the total benefit gained were from the whole improvements and it was necessary to try to separate the benefit for every single project.
Table 6 showed analysis results of cost saving after implementation of the project.Table 7 showed analysis of investment cost of every projects.
From the preliminary analysis of cost and benefit, it is clear that only one year after implementation the benefit gain would exceed the total cost and the B/C ratio is almost double.
For the financial analysis, it was concluded that the total trip interchanges within the inner area and passing the area would have to pay for the charge. The total amount of collection would be as high as 80-90 million Baht a day. The total collection should be reinvested in public transport and other transport projects that would lead to improvement of level of services of public transport and to tackle traffic congestion and other traffic problems.
9. Environmental Evaluation
Environmental study was concentrated only on air pollution, since the problem was clear and serious. The study was carried out partly by Thailand Environmental Institute and Department of Pollution Control, Ministry of Science and Technology (MoST). The study methodology was formulated as follows.
For the environmental control schemes, the study set up 3 main control strategies in order to evaluate their effectiveness and to understand the end results of the ambient air condition. Those strategies are as shown in Table 8. Target of the total amount of pollutant reduction is as shown in Figure 2. Results of the study is as explained in Table 9. The main conclusion is: even if all the plans and committed projects (both in transport and pollution control sectors) were invested on schedule, the air pollution condition would not be better than the present condition. The ambient air pollution would be better only if the traffic restrained projects and other public transport improvement were implemented.
10. Conclusion.
The transportation plans that resulted from problems oriented study only would be suitable for GBA. Then the detail study related to necessity and justification of each project should follow not otherwise. There are numerous lessons learned from experience especially related to heavy investment on expressway and main roads which yielded unfavorable traffic condition. From this study, the main strategy to tackle the congestion problem is to introduce reasonable and flexible traffic restrained projects plus improvement in public transport plus long range demand management strategy that concentrate on land use control. The Area Pricing scheme would be one of the most important projects to be implemented in GBA. This is the only scheme that would alleviate congestion and reduce air pollution problems in GBA.
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