Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles (2018) / Chapter Skim
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20 This chapter summarizes the process used to select the CAV applications and evaluate the available modeling frameworks for use in this project. 3.1 Selection of CAV Applications Given that the objective of this research was to evaluate the conditions amenable for dedicating lanes to CAVs, the team evaluated the various CV applications that have been envisioned by the U.S.DOT.
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Connected and Automated Vehicle Applications 21 harmonization, to be enforced to gain environmental benefits. In a CAV environment, an eco-lane would be a DL that provides exclusive access to vehicles controlled using an energy/ emissions-optimized CACC system or a speed harmonization system.
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22 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles • Application 8: CACC. This application aims to dynamically adjust and coordinate cruise control speeds among platooning vehicles to improve traffic flow stability and increase throughput.
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Connected and Automated Vehicle Applications 23 significantly (Figure 3.1)
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24 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles phase space density (p) represents the expected number of vehicles driving with speed (V)
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Connected and Automated Vehicle Applications 25 CACC-equipped vehicles for both scenarios. No validation efforts were made, but this model produced reasonable results as demonstrated by the density changes in these figures.
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26 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles 3.2.1.2 Volpe CAV Analysis Framework Smith et al.
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Connected and Automated Vehicle Applications 27 • CACC, • Automated Platooning, and • Full Automation in a Controlled Environment. As shown in Figure 3.7, the framework is triggered from the safety and mobility sub-models.
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28 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles At publication of this report, the sub-model for vehicle mobility remained in the development stage, utilizing a microscopic traffic simulation platform. Employing a step-wise approach, the entire framework is designed to evaluate selected AV applications in a simple single-lane condition and expand to more complex road networks.
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Connected and Automated Vehicle Applications 29 increase with respect to the combination of CACC and HIA on the left and the combination of CACC and ACC on the right (Shladover et al.
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30 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles environmental impacts (e.g., exhaust-gas emission, noise, fuel consumption)
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Connected and Automated Vehicle Applications 31 Source: Van Arem et al.
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32 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles the behavior of individual driver's longitudinal and lateral driving maneuvers and macroscopic approach to handle collective dynamics of traffic flow (like density, flow, shockwaves) to analyze the traffic performance.
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Connected and Automated Vehicle Applications 33 Vissim to conduct evaluations of the impact of CACC DL on traffic flow. In their 2014 study, Lee et al.
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34 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles Source: Lee et al.
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Connected and Automated Vehicle Applications 35 vehicles was less than the critical safety threshold, and the speed difference between the leading vehicle and the following vehicles in the target lane was lower than the threshold, a lane change was activated. Notably, the CACC-equipped vehicles' lateral behavior was not calibrated; this is because no knowledge yet exists of how the human drivers of non-CACC-equipped vehicles will behave when joining or leaving CACC platoons.
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36 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles Source: Lee et al.
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Connected and Automated Vehicle Applications 37 Model were unavailable for use by the project team. Because the Volpe framework was under development, it was dropped from the evaluation.
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38 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles d. Modeling incidents/accidents; e.
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Connected and Automated Vehicle Applications 39 the Aimsun- and Vissim-based CACC modeling tools developed by Shladover et al.
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40 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles tools. Utilizing commercial-off-the-shelf products, Aimsun- and Vissim-based CACC modeling tools are fully capable of customizing recorded MOEs.
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Connected and Automated Vehicle Applications 41 measures for societal justice such as equity and perception of exclusivity were excluded from the table. As seen in Table 3.7, almost all mobility measures are available through the selected modeling tools.
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42 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles assessing safety impacts, the NCHRP project team could use the Surrogate Safety Assessment Model (FHWA 2008a) in this study by integrating it with the Aimsun or VISSIM modeling tools to enable estimates of surrogate measures such as time to collision, post encroachment time, and speed difference (delta V)
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Connected and Automated Vehicle Applications 43 to minimize shockwaves and potentially improve system mobility by detecting congestion or queues downstream (Ma et al.
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44 Dedicating Lanes for Priority or Exclusive Use by Connected and Automated Vehicles Study CAV/CAV V2I or V2V Control Algorithms Lu et al.
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Connected and Automated Vehicle Applications 45 A COM-based application was used to implement this DSH algorithm. The application watched for inputs from freeway sensors (data collection devices)
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