1) Forecasting trip generation and concentration (trip distribution)
The "4-step estimation method" mentioned earlier forecasts a distributed traffic volume by adding distribution (flow) patterns derived from trip generation and concentration. However, as mentioned earlier, because the OD subject to forecast is limited in the Bangkok area, this study will also forecast a distributed traffic volume in the forecast of trip generation concentration.
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The generations and concentration of traffic volumes for the forecast year are estimated based on the generation and concentration of traffic volumes by different zones in 1995. Because the fluctuations in the generation and concentration of traffic volumes seem to have a close correlation with population fluctuations, the increase rate of generation and concentration of traffic volume by different zones is estimated from the population increase rate. Future population structures are based on the forecast made by the Ministry of Transport and Communications.
Table 5.5-3 indicates the results of forecasting the generation and concentration of traffic volumes. The entire trip generation and concentration in the area subject to forecasting for the year 2003 is estimated about 1.1 times more than the traffic volume in 1995. In other words, such traffic volume will be achieved when an annual increase rate of 1.2 % continues until the year 2003.
