Leveraging existing high-occupancy vehicle lanes for mixed-autonomy traffic management with emerging connected automated vehicle applications

2020 ◽  
Vol 16 (3) ◽  
pp. 1375-1399 ◽  
Author(s):  
Yi Guo ◽  
Jiaqi Ma
Author(s):  
Marilo Martin-Gasulla ◽  
Lily Elefteriadou

In the advent of new automation and communication technologies, the introduction of connected and autonomous vehicles (CAVs) can make efficient use of the space on our road networks. Since roundabouts suffer from lower efficiencies when traffic flows are unbalanced and unfamiliar drivers are present, CAVs have the potential to improve traffic operations, reducing lost time and inefficiency in gap-usage. The aim of this research is to take advantage of those recently available technologies to design a traffic management system for roundabouts. Such a system can provide CAVs with optimal trajectories to negotiate the roundabout, maximizing throughput and minimizing control delay. The rule-based Roundabout Manager algorithm developed considers the roundabout as a whole system, assessing the priority of incoming vehicles on a first-come-first-served scheduling to solve conflicts. The management system takes into consideration the geometry of the roundabout, including the flared entries and exits and the location of conflict sections based on merging trajectories of vehicles in negotiating the roundabout. To illustrate the operation of the algorithm, a total of 15 undersaturated demand scenarios with 10 replications per scenario were simulated. From the results, it can be concluded that the system can reduce control delay for medium demand scenarios, maximizing the throughput for all demand scenarios. The Roundabout Manager can work in real time providing optimized trajectories in less than 0.02 s at any traffic flow rate simulated.


Author(s):  
David L. Schrank ◽  
Timothy J. Lomax

Measuring the effects of transportation system improvements has long been a challenge. Two estimates—the congestion index method and the travel delay method—are used to produce a range of possible benefits resulting from the implementation of transportation projects and programs. The congestion index method uses the roadway congestion index (RCI), and its relationship with congestion cost per capita, to estimate the benefit derived from operational improvements. The RCI provides an areawide assessment of congestion based on freeway and principal arterial street system daily vehicle kilometers of travel per lane kilometer data. The travel delay method calculates congestion cost by associating the value of time, cost of fuel, and cost of operating commercial vehicles with travel delay estimates. These two methods are used to estimate the effects of three types of transportation system improvement projects/programs—freeway traffic management system, high-occupancy vehicle lanes, and regional computerized traffic signal system— implemented on the freeway and principal arterial street system in Houston, Texas. Although only three operational projects/programs are discussed, it is possible to effectively evaluate the implementation of many other improvements using this methodology.


2014 ◽  
Vol 590 ◽  
pp. 386-389
Author(s):  
Xiu Chun Guo

ITS deployment was adopted to improve traffic operation. Actuated control and advanced traffic management have been deployed in the project area. Driving is a multitasking activity that requires drivers to manage their attention between various driving-and non-driving-related tasks. This paper discusses the problem of modeling realistic and human-like behaviors on simulated highway systems by developing a framework. This framework consists of four units that are the perception unit, the emotions unit, the decision-making unit, and the decision-implementation unit. This paper has researched on the automatic vehicle driving mode (The Advanced Vehicle Control and Safety System) at the four-lane highway. Automated vehicle decision-making procedure is discussed in this research. Two safety indices of automate vehicle driving are explored. In real experiment, TBC index may be good for commending evaluating automate vehicle driving behavior.


2015 ◽  
Vol 5 (1) ◽  
pp. 3-17 ◽  
Author(s):  
Michaela Schwarz ◽  
K. Wolfgang Kallus

Since 2010, air navigation service providers have been mandated to implement a positive and proactive safety culture based on shared beliefs, assumptions, and values regarding safety. This mandate raised the need to develop and validate a concept and tools to assess the level of safety culture in organizations. An initial set of 40 safety culture questions based on eight themes underwent psychometric validation. Principal component analysis was applied to data from 282 air traffic management staff, producing a five-factor model of informed culture, reporting and learning culture, just culture, and flexible culture, as well as management’s safety attitudes. This five-factor solution was validated across two different occupational groups and assessment dates (construct validity). Criterion validity was partly achieved by predicting safety-relevant behavior on the job through three out of five safety culture scores. Results indicated a nonlinear relationship with safety culture scales. Overall the proposed concept proved reliable and valid with respect to safety culture development, providing a robust foundation for managers, safety experts, and operational and safety researchers to measure and further improve the level of safety culture within the air traffic management context.


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