Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles (2018) / Chapter Skim
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71 Using modeling and simulation, the research team evaluated the specific conditions and factors that influence the performance of CAV applications when such users are in a DL. The team used a four-step evaluation approach to evaluate the performance of CAV applications under different conditions and to quantify factors that influence these impacts (see Figure 5.1)
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72 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles 5.1.1 I-66 in Northern Virginia Interstate Highway 66 (I-66) in Northern Virginia was the primary case study site for this project.
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Analysis and Evaluation Approach 73 Therefore, the project team collected field traffic data for vehicle counts, incident records, spot speeds, and probe data from the Virginia Department of Transportation (Virginia DOT)
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Source: NCHRP 20-102(08) project team; base map from www.openstreetmap.org.
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Analysis and Evaluation Approach 75 Figure 5.5. I-66 westbound travel time field and simulation data with calibration threshold.
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76 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles GEH statistic functions as an empirical parameter similar to the chi-squared statistic that compares two sets of traffic volumes. 5.1.1.1 Baseline System Performance This section expands on the baseline system performance.
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Analysis and Evaluation Approach 77 computation of the throughput values. The time-series in Figure 5.7 shows that the volumes increase between 5:00 p.m.
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78 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles The US-101 freeway carries between 200,000 and 250,000 AADT, of which 15% to 25% consists of HOV-2+ vehicles. El Camino Real carries between 25,000 and 50,000 average daily traffic.
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Analysis and Evaluation Approach 79 Figure 5.10. Baseline performance in northbound (peak direction)
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80 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles The analysis period used was between 2:30 p.m.
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Analysis and Evaluation Approach 81 based on recommendations from the California Partners for Advanced Transportation Technology, which is leading the CACC research on behalf of U.S.DOT's Exploratory Advanced Research Program. The modified CACC algorithm included the following driver behavior models: • Preferential Lane Logic.
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82 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles The String Terminator behaves as a CACC-equipped vehicle but does not let another CAV join the platoon. This logic also is performed through VISSIM's COM interface.
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Analysis and Evaluation Approach 83 control or with vehicles whose human drivers perceive the new speed as informational only and may choose not to follow the harmonized speed recommendations. 5.2.3 Combined Modeling of Applications The project team also modeled CACC and DSH applications in combination.
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84 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles Figure 5.14. CACC and DSH working together on a platoon of CAVs.
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Analysis and Evaluation Approach 85 exported the measures of effectiveness to a performance measures table. (The scenario table and performance measures table are discussed further in later sections of this chapter.)
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86 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles Table 5.3 shows a preliminary list of evaluation scenarios. In the table, each scenario is described in terms of the case study site, demand, market penetration, users allowed on the DLs, number of DLs, applications modeled, and any special cases.
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Analysis and Evaluation Approach 87 ID Site Demand MPR (%) DL Users CAV Applications Special Cases 1 I-66 Typical p.m.
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88 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles 5.4.2 Safety Performance Measures Safety-based performance measures can contribute significantly to the development of guidance for dedicating lanes to CAVs. Specifically, they can help assess safety features that are required in the infrastructure when lanes are dedicated to CAVs under different conditions.
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Analysis and Evaluation Approach 89 • The conditions of travel during part or all of a trip may be unpleasant for the travelers and involve tension, fatigue, or discomfort. For this study, the project team utilized average value of VTTS based on personal and business trips as per 2014 guidance.
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90 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles only the direct performance of the network. For example, the team did not consider impacts due to increased VMT that might be caused by the increase in mobility performance of the network.
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