Assessing the Impact of Turning Vehicles on Pedestrian Level of Service at Signalized Intersections

2007 ◽  
Vol 2027 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Sarah M. L. Hubbard ◽  
Ramzi J. Awwad ◽  
Darcy M. Bullock
Keyword(s):  
Signalized Intersections ◽  
Level Of Service ◽  
Pedestrian Level Of Service ◽  
The Impact

Modeling Pedestrian Level of Service at Signalized Intersection Under Mixed Traffic Conditions

2017 ◽  
Vol 2634 (1) ◽  
pp. 86-94 ◽  
Author(s):  
S. Marisamynathan ◽  
P. Vedagiri
Keyword(s):  
Linear Regression ◽  
Signalized Intersections ◽  
Level Of Service ◽  
Delay Model ◽  
Mixed Traffic ◽  
Threshold Values ◽  
User Perceptions ◽  
Traffic Conditions ◽  
Fcm Clustering ◽  
Pedestrian Level Of Service

Developing countries such as India need to have the proper pedestrian level of service (PLOS) criteria for various facilities to help in planning, designing, and maintaining pedestrian facilities. Thus, the objective of this study was to develop a suitable method for estimating the PLOS model under mixed traffic conditions and also to define threshold values for PLOS classification at signalized intersections. First, the data were collected with video and a user perceptions survey at eight selected signalized intersections in Mumbai, India. Second, pedestrian crossing behaviors were modeled according to arrival pattern, crossing speed, noncompliance behavior, and pedestrian–vehicular interaction. Third, a pedestrian delay model was proposed by considering crossing behavior variations and subsequent validation with field data. Fourth, significant variables were identified on the basis of the Pearson’s correlation test with user’s perceptions score. Fifth, the conventional linear regression (CLR) technique was explored to determine the PLOS. To overcome the limitations of the CLR technique, fuzzy linear regression (FLR) was done to develop a PLOS model that fits mixed traffic conditions in India. Two models were validated, and their statistical performance results indicate that the FLR model predicts the PLOS score more precisely. Finally, k-means and fuzzy C-means (FCM) clustering techniques were applied to classify the PLOS score, and the results were compared by time complexity value and field values. The performance evaluation results indicate that the k-means method saves time but fails to produce more reliable threshold values, and the FCM method produces more accurate and efficient threshold values for the PLOS score at signalized intersections under mixed traffic conditions.

scholarly journals Impact Assessment of Driver Distraction by Cellphone on Start-up Lost-time and Average Saturation Headway at Signalized Intersections Based on Vehicle Position in the Queue

2021 ◽  
Vol 49 (4) ◽  
pp. 359-368
Author(s):  
Nawaf Alshabibi
Keyword(s):  
Signalized Intersections ◽  
Signalized Intersection ◽  
Level Of Service ◽  
Total Delay ◽  
Main Hypothesis ◽  
Start Up ◽  
Lost Time ◽  
Vehicle Position ◽  
Secondary Hypothesis ◽  
The Impact

Cellphone usage has a significant impact on signalized intersections' capacity and level of service. This study investigated the impact of cellphone usage on signalized intersection capacity and level of service in Dammam Metropolitan Area, Saudi Arabia. The data included 183 useful cycles and 2407 start-up lost time and average saturation headway values at cycles with cellphone usage and cycles without cellphone usage at 24 signalized intersections. The main hypothesis of the study is that cellphone usage increases the start-up lost time at signalized intersection capacity. The secondary hypothesis is that cellphone usage increases the average saturation headway at signalized intersections. Normal distribution and z-test were conducted to assess whether there is a significant increase in average saturation headway and start-up lost time. The study found a significant increase in start-up lost time of about 0.7 seconds but found no significant increase in average saturation headway due to cellphone usage. Also, start-up lost time increases as vehicles of cellphone users get closer to the stop line of the signalized intersections. Thus, cellphone usage decreases the progression of 13 vehicles per hour due to a reduction in effective green time, increases total delay, and deteriorates the level of service. The study can assist transportation and traffic officials to optimize signal operation to mitigate the impact of cellphone usage and improve urban transportation.

Efficient Fault Tolerance on Cloud Environments

2018 ◽  
Vol 8 (3) ◽  
pp. 20-31 ◽  
Author(s):  
Sam Goundar ◽  
Akashdeep Bhardwaj
Keyword(s):  
Fault Tolerance ◽  
Web Applications ◽  
Fault Tolerant ◽  
Cloud Services ◽  
Level Of Service ◽  
Cloud Environments ◽  
Computing Environments ◽  
Service Assurance ◽  
Mission Critical ◽  
The Impact

With mission critical web applications and resources being hosted on cloud environments, and cloud services growing fast, the need for having greater level of service assurance regarding fault tolerance for availability and reliability has increased. The high priority now is ensuring a fault tolerant environment that can keep the systems up and running. To minimize the impact of downtime or accessibility failure due to systems, network devices or hardware, the expectations are that such failures need to be anticipated and handled proactively in fast, intelligent way. This article discusses the fault tolerance system for cloud computing environments, analyzes whether this is effective for Cloud environments.

Architecting Fail-Safe Supply Networks

2016 ◽  
Author(s):  
Shabnam Rezapour ◽  
Ramakrishnan S. Srinivasan ◽  
Jeffrey Tew ◽  
Janet K. Allen ◽  
Farrokh Mistree
Keyword(s):  
Service Level ◽  
Level Of Service ◽  
Supply Network ◽  
Flow Dynamic ◽  
Supply Networks ◽  
Uncertainty Sources ◽  
High Magnitude ◽  
Stochastic Events ◽  
Fail Safe ◽  
The Impact

A fail-safe network is one that mitigates the impact of different uncertainty sources and provides the most profitable level of service. This is achieved by having 1) a structurally fail-safe topology against rare but high magnitude stochastic events called disruptions and 2) an operationally fail-safe flow dynamic against frequent but low magnitude stochastic events called variations. A structurally fail-safe network should be robust and resilient against disruptions. Robustness and resilience respectively determine how well and how quickly disruptions are handled by the SN. Flow planning must be reliable in an operationally fail-safe supply network against variations to provide the most profitable service level to customers. We formulate the problem of designing/redesigning fail-safe supply networks as a compromise Decision Support Problem. We analyze the correlations among robustness, resilience, and profit for supply networks and propose a method for supply network managers to use when they need to find a compromise among robustness, resilience, and profit.

Design and Performance Analysis of Pedestrian Crossing Facilities for Continuous Flow Intersections

2005 ◽  
Vol 1939 (1) ◽  
pp. 133-144 ◽  
Author(s):  
Ramanujan Jagannathan ◽  
Joe G. Bared
Keyword(s):  
Continuous Flow ◽  
Level Of Service ◽  
Vehicular Traffic ◽  
Average Delay ◽  
Qualitative And Quantitative ◽  
Traffic Performance ◽  
Pedestrian Traffic ◽  
Pedestrian Level Of Service ◽  
And Performance ◽  
Pedestrian Crossing

Although concepts of the continuous flow intersection (CFI) have been around for approximately four decades, minimal or no literature describing studies that have analyzed pedestrian traffic performance at these intersections is available. Several studies have reported on the qualitative and quantitative benefits for the vehicular traffic performance of CFIs in comparison with the benefits for the vehicular traffic performance of conventional intersections but have provided minimal or no discussion about pedestrian traffic performance. As a novel intersection design, many important considerations are required to design pedestrian accesses and crossings at CFIs without compromising pedestrian safety and vehicular traffic performance. In this paper, the design methodologies for providing pedestrian access and related pedestrian signal timings are discussed. Modeling was conducted on three typical geometries for CFIs with base signal timings optimized for vehicular traffic performance. The results indicate an acceptable pedestrian level of service of B or C on the basis of the average delay per stop experienced by any pedestrian for pedestrian crossings at the typical CFI geometries modeled. All pedestrians served at the CFIs are accommodated within two cycles for a typical signal cycle length ranging from 60 to 100 s.

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