| Title | Traffic Flow Characteristics of Toll Plazas, Tunnels, and Upgrade Segments on Freeways and other Roadways (3/3) |
| Dept | Transportation Planning and Land Transport Division |
| Year | 2013 |
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| Price | |
| Summary | In 2010 the Institute of Transportation (IOT) initiated a three-year project to explore the traffic flow characteristics of the toll stations, tunnels, and sloped sections on freeways and expressways. This project was year 3 project and involved the completion of the following 5 tasks: (1) identifying the traffic flow characteristics of the tunnels on National Highway 3 (NH3); (2) integrating current and previous findings about the flow characteristics of tunnels to develop a new chapter “Highway Tunnels” for future editions of Highway Capacity Manual (HCM); (3) revising HCM Chapter 10 concerning the analysis of urban tunnels; (4) developing a plan for collecting data regarding the traffic flow characteristics of the sloped sections on various types of highways; and (5) developing a prototype simulation model for analysis of the operations of highway sloped sections. The analysis of NH3 data suggests that the tunnels on NH3 had greater capacities than those on NH5. Furthermore, the capacities of the tunnels on both highways increased with average free-flow speed. However, the increase became insignificant when the average free-flow speed achieved a certain level. Field data also revealed that the presence of urban tunnels resulted in significantly lower downstream static vehicle discharge headways in comparison with the typical discharge headways on level streets. The impact depends of the average grade on the downstream intersection approach. A review of the state of the practice in capacity and level of service of sloped sections showed a need for Taiwan to develop simulation software. This report details the findings of the aforementioned tasks. Appendixes D and E of the report respectively present new chapter of the HCM, specifically, “Highway Tunnels,” and the revised Chapter 10 “Urban Tunnels.” |
| Post date | 2013/05/30 |
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