Corridor Ranking with Automated Traffic Signal Performance Measurers

Automated traffic signal performance measures (ATSPMs) are being deployed with increasing frequency. This session presents a method of evaluating corridor performance at the system level using high-resolution data. This method develops five subscores for the areas of communication, detection, safety, capacity allocation, and progression; these are given a letter grade based on quantitative performance measures, with context-appropriate scales. An aggregate score for each corridor is determined using the lowest subscore of each of the five areas

Corridor Ranking with Automated Traffic Signal Performance Measurers

Automated traffic signal performance measures (ATSPMs) are being deployed with increasing frequency. This session presents a method of evaluating corridor performance at the system level using high-resolution data. This method develops five subscores for the areas of communication, detection, safety, capacity allocation, and progression; these are given a letter grade based on quantitative performance measures, with context-appropriate scales. An aggregate score for each corridor is determined using the lowest subscore of each of the five areas

Roadway System Assessment Using Bluetooth-Based Automatic Vehicle Identification Travel Time Data

This monograph is an exposition of several practice-ready methodologies for automatic vehicle identification (AVI) data collection systems. This includes considerations in the physical setup of the collection system as well as the interpretation of the data. An extended discussion is provided, with examples, demonstrating data techniques for converting the raw data into more concise metrics and views. Examples of statistical before-after tests are also provided. A series of case studies were presented that focus on various real-world applications, including the impact of winter weather on freeway operations, the economic benefit of traffic signal retiming, and the estimation of origin-destination matrices from travel time data. The technology used in this report is Bluetooth MAC address matching, but the concepts are extendible to other AVI data sources

Evaluation of Arterial Signal Coordination with Commercial Connected Vehicle Data: Empirical Traffic Flow Visualizations and Performance Measures Considering Multiple Origin-Destination Paths

Emerging connected vehicle (CV) data sets have recently become commercially available that enable analysts to develop a variety of powerful performance measures without a need to deploy field infrastructure. This paper presents a several tools using CV data to evaluate the quality of signal progression. These include both performance measures for high-level analysis as well as visualizations to examine details of coordinated operation. With the use of CV data, it is possible to assess not only the movement of traffic on the corridor but also to consider its origin-destination (O-D) path through the corridor, and the tools can be applied to select O-D paths or to all O-D paths in the corridor. Results for real-world operation of an eight-intersection signalized arterial are presented. A series of high-level performance measures are used to evaluate overall performance by time of day and direction, with differing results by metric. Next, the details of the operation are examined with the use of two visualization tools: a cyclic time space diagram, and an empirical platoon progression diagram. Comparing visualizations of only end-to-end journeys on the corridor with all journeys on the corridor reveals several features that are only visible with the latter. The study demonstrates the utility of CV trajectory data for obtaining high-level details as well as drilling down into the details

Investigation of Self-Organizing Traffic Signal Control with Graphical Signal Performance Measures

Adaptive signal control is the subject of an increasing amount of research, as well as development and implementation. Most existing adaptive control systems achieve coordination by applying system control as a constraining layer on top of local control. Some researchers have suggested that, with the right local-control logic, coordination might be achieved as an dynamically emergent phenomenon without the need for a management layer. This paper explores the potential of a self-organizing signal control algorithm using a variety of performance measures. First, the initially reported algorithm performance is reproduced in an idealized environment; next, the algorithm is applied in a realistic road network to compare its performance against actuated-coordinated control, with and without pedestrian phases. Comparisons are made under (1) the same base volumes used to design the actuated-coordinated timing plan; and (2) a variant volume. Self-organizing control is found to be more flexible than coordinated control, and induces a tradeoff in performance among different movement types. Delay reductions of 38–56% are seen in an environment without pedestrian phases. However, with pedestrian phases in recall, self-organizing control performs worse (39% increase in delay) under base volumes, and achieves a weak benefit (6% reduction in delay) under the variant volume. Because of the large total delay reductions in some scenarios, the results show promise for future development

A homoleptic phosphine adduct of Tl(I)

A homoleptic phosphine adduct of thallium(I) supported by a tris(phosphino)borate ligand has been isolated and structurally characterized