The National Academies Press

Currently Skimming:

Pages 124-152

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.

From page 124... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics CHAPTER 6 ANALYSIS, MODELING, AND SIMULATION FOR ATM Chapter Highlights and Objectives To develop and implement effective active traffic management (ATM) strategies, it is essential to have a comprehensive understanding of the underlying principles and a robust analytical framework for assessment throughout the planning and implementation process. Read the entire page →
From page 125... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics The AMS Framework An AMS framework for transportation involves a systematic approach to evaluating and improving transportation systems, including collecting and analyzing data on transportation systems, developing mathematical and statistical models to represent the behavior of these systems, and using simulation tools to test and evaluate the performance of these models. By using this framework, transportation engineers and planners can identify areas of improvement in transportation systems, test different strategies for improving transportation efficiency and safety, and optimize transportation networks to better serve the needs of communities. Read the entire page →
From page 126... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics The following bullets describe these components in some detail: • Scenario manager: Creates multiple scenarios for the analyst to choose from (e.g., lane closure due to incidents, varying traffic patterns, etc.) Read the entire page →
From page 127... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics • Sketch-planning tools: Evaluate alternatives or projects without performing a detailed traffic analysis and are appropriate for high-level analysis. • Travel demand models: Predict future travel demand based on existing conditions and projections of socioeconomic characteristics. Read the entire page →
From page 128... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics become more complicated in analyzing queues because they may extend upstream and affect other locations. Some gaps in the HCM procedures also exist when simulating ATM strategies. Read the entire page →
From page 129... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics behavior if the significant effort to calibrate the model has been successful. Mesoscopic simulation, on the other hand, is less computationally intensive but provides a less detailed model of driver behavior (Waller at al. Read the entire page →
From page 130... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics Figure 6-2. AMS analysis levels for ATM. Read the entire page →
From page 131... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics • Dynamic lane reversal: Both microscopic and mesoscopic simulation tools can be used to model the impacts of dynamic lane reversal. Microscopic models can be used to analyze how egress/ingress locations impact traffic flow. Read the entire page →
From page 132... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics Table 6-1. Applicability of modeling tools for analysis of ATM strategies. Read the entire page →
From page 133... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics ATM strategies can be modeled in conjunction with strategies tied to transit, such as transit signal priority. The level of tool(s) Read the entire page →
From page 134... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics Table 6-2. Modeling applications (Source: adapted from Yelchuro et al. Read the entire page →
From page 135... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics Data Requirements Applying an AMS framework to ATM strategies will require both historical and real-time data as inputs into the scenario manager, where the data are processed into standardized formats and scenarios are developed. It is important to note that there may be instances where the data are inconsistent or in an incompatible format. Read the entire page →
From page 136... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics Traffic Management and Control Systems Signaling and signage systems, such as ramp metering systems, traffic control systems, variable message signs, and static signage, are used to influence and control driver decision-making and can be fixed or autonomous. Components of traffic management and control systems include the following: • Traffic control systems: Provide for the integration and adaptive control of the freeway and surface street networks to improve the flow of traffic, give preference to transit and other high occupancy vehicles, and minimize congestion. Read the entire page →
From page 137... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics For safety-oriented applications, the wireless communication will likely be low-latency DSRC. For non-safety-critical applications, the choice of wireless media and its performance can vary greatly depending on the infrastructure architecture, geographical coverage, and network topology. Read the entire page →
From page 138... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics of weather events, the interaction of weather conditions with the road surface, and the type and availability of appropriate transportation management devices and systems (Vasudevan and Wunderlich 2013) Read the entire page →
From page 139... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics It is important to note that the segment-level, corridor-level, and regional-level data requirements have been consolidated, and historical data have been categorized based on distinct ratings, as shown in Figure 6-4. Figure 6-4. Read the entire page →
From page 140... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics calibration objective function should be chosen, and the analyst should seek to minimize the error between model output and field measurement. The general calibration objective function can be described as an optimization problem with the objective of minimizing the relative gap measure comparing the observed and fitted measurement values. Read the entire page →
From page 141... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics Driver Behavior Algorithms Driver behavior can be captured using car-following and lane-changing algorithms, which govern vehicular traffic movement. The parameters of these algorithms need to be adjusted for a specific region. Read the entire page →
From page 142... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics ODME Calibration of an OD matrix involves several sub-steps, if applicable (see Figure 6-6) Read the entire page →
From page 143... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics Performance Measures Once a model has been properly calibrated and validated, a base model is developed and used as a basis for comparison. Alternate scenarios can then be developed and simulated to obtain various performance measures and generate the appropriate output. Read the entire page →
From page 144... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics Table 6-3. Performance measures per ATM strategy for corridor-level analysis. Read the entire page →
From page 145... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics Time Reliability of the HCM (NASEM 2022) provides methodologies for incorporating travel time reliability into the analytic procedures for freeway facilities and urban streets. Read the entire page →
From page 146... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics In addition to the MOEs listed above, crash rates and number of injuries by severity are other measures that reflect how traffic safety is affected by ATM strategies. These metrics are separately estimated and compared for the period before and after the implementation of a strategy. Read the entire page →
From page 147... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics Table 6-5. Performance measures per ATM strategy for regional-level analysis. Read the entire page →
From page 148... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics Chapter References Chiu, Y.-C. Read the entire page →
From page 149... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics Volume 58, Part A, pp 146–159. https://doi.org/10.1016/j.trc.2015.07.014. Read the entire page →
From page 150... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics Research Board, National Academies. Second Strategic Highway Research Program Publication S2-L08-RW-1. Read the entire page →
From page 151... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics PRE-PUBLICATION DRAFT -- Unedited Text and Graphics Read the entire page →
From page 152... ... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics PRE-PUBLICATION DRAFT -- Unedited Text and Graphics Read the entire page →

From page 124...

... PRE-PUBLICATION DRAFT -- Unedited Text and Graphics CHAPTER 6 ANALYSIS, MODELING, AND SIMULATION FOR ATM Chapter Highlights and Objectives To develop and implement effective active traffic management (ATM) strategies, it is essential to have a comprehensive understanding of the underlying principles and a robust analytical framework for assessment throughout the planning and implementation process.