A study of vehicular headway distribution on the second stage expressway in Bangkok | |
| Author | Aye Aye Myint |
| Call Number | AIT RSPR no. TE-97-02 |
| Subject(s) | Traffic flow--Thailand--Bangkok Express highways--Thailand--Bangkok |
| Note | A research submitted in partial fulfilment of the requirements for the degree of Master of Engineering, School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | The time headway between vehicles is an important flow characteristic that affects the safety, level of service, driver behaviour and capacity of a transportation system. This research analyzed vehicle headway distributions along the Second Stage Expressway in Bangkok. The study also investigated the merging behaviour of drivers along the on-ramp of this expressway. In this study, Pearson type ID distribution model family was applied to analyze the headway distributions along the Second Stage Expressway. Traffic flows on all three lanes varied from medium to heavy flow conditions at two different study periods. So, two distribution models; Pearson type ID and shifted negative exponential distribution models, which have two parameters; shifted value a and A. (reciprocal of mean headway), were selected to analyze the headway distributions on the Second Stage Expressway. Statistical analysis indicated the observed headway data on the shoulder lane were satisfactory represented by shifted negative exponential distribution. Then, the headway distributions on three lanes and on different vehicle types were also analyzed by shifted negative exponential distribution model. Although this shifted negative exponential distribution model can not fit well the observed data on all three lanes at two different study periods, it can fit very well the observed frequencies of headway data on different vehicle types. A study of driver merging behaviour on the Second Stage Expressway in Bangkok indicated that the.critical gap of Thai drivers is about 3.6 seconds. When the critical gap of Thailand is compared with Singapore and Japan, the critical gap of Thailand (3.6 seconds) is greater than that of Singapore (3 seconds) and Japan (3.17 seconds) for expressway merging. |
| Year | 1998 |
| Type | Research Study Project Report (RSPR) |
| School | School of Civil Engineering |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Transportation Engineering (TE) |
| Chairperson(s) | Yordphol Tanaboriboon; |
| Examination Committee(s) | Nakatsuji, Takashi ;Chotchai Charoenngam; |
| Scholarship Donor(s) | Asian Development Bank, Japan; |
| Degree | Research Studies Project Report (M. Eng.) - Asian Institute of Technology, 1998 |