| Summary |
The “Taiwan Highway Capacity Manual” (THCM) published by the IOT provides an important reference for the planning, design, and evaluation of highway capacity and level of service. The Chapters related to the merging area for on-ramp and diverging areas for off-ramp was developed based on limited site-data collected for the National freeway of Taiwan, and cannot meet the current analysis requirements. IOT is preparing to revise Chapter 5 "Freeway On-Ramp Sections" and Chapter 6 "Freeway Off-Ramp Sections" of the Manual. In order to accomplish this task, the "Advanced
Planning for Traffic Characteristics Survey of Freeway Merging and Diverging Area" was completed in 2018 to clarify the main types of merging area for on-ramp and diverging area for off-ramp. In 2019, IOT initialized a three-year research project to analyze the most types of merging area for on-ramp and diverging area for off-ramp in Taiwan, and established the capacity and level of service analysis method of freeway and expressway merging and diverging area, and supplemented the analysis method of the expressway capacity and level of service. The themes of this three-year research work are (i) isolated merging areas for on-ramp and isolated diverging areas for off-ramp, (ii) non-isolated
merging areas for on-ramp and non-isolated diverging areas for off-ramp, and (iii) expressway merging and diverging areas.
This year is the second year of this research project, and the target of analysis is the non-isolated merging areas for on-ramp and non-isolated diverging areas for off-ramp. This Project explores the on-ramp and off-ramp types where there exist other ramps within 1 kilometer upstream or downstream of the subject ramp; and integrated with the results of the first-year study, the proposed methodology establishes the capacity and level of service analysis method of freeway merging and diverging areas suitable for the traffic conditions in Taiwan. |
