Title Capacities and Traffic Flow Characteristics of the Rural and Suburban Multilane Highways in Taiwan (III)
Dept Transportation Planning and Land Transport Division
Year 2005
Month
Price
Summary In 2002 the Institute of Transportation, Ministry of Transportation and Communications, initiated a three-phase project to revise Chapter 11 of Taiwan Area Highway Capacity Manual. The revised chapter is intended to provide tools for analyzing the capacities and levels of service of uninterrupted flow facilities, individual signalized intersections, and arterials. To this end, the following tasks are carried out in Phase III of the project: (1) Collect field data to identify the lane-utilizing patterns of different types of vehicles
(2) Collect field data to identify the queue-discharge characteristics and the speed variations between intersections
(3) Analyze and use field data to calibrate the Highway Traffic Systems Simulation (HTSS) Model
(4) Revise Chapter 11 of the Taiwan Area Highway Capacity Manual and prepare a HTSS User Manual. Field data show that the influence zone of a signalized intersection is about 3 km. Therefore, uninterrupted flow sections do not exist unless the spacing between signalized intersections is more than 3 km. It is also found that the speed-flow relationships on uninterrupted flow sections are governed by the free-flow speeds of individual sections. The revised Chapter 11 provides a set of representative speed-flow relationships as a basis for analyzing the levels of service of uninterrupted flow sections. Observed queue discharge characteristics do not conform to the traditional concept of saturation flow. Alternative methods are thus developed for estimating the capacities of four types of lanes that have protected movements. In general, the traffic operations at individual intersections and arterials are too complex to be modeled and analyzed analytically. Therefore HTSS model provides a practical means for analysis of such facilities. This model has been tested and calibrated in many respects. With further testing and calibration, the HTSS model can also become a useful tool for the development of analytical models.
Post date 2005/10/20
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