scholarly journals SATURATION FLOW ESTIMATION AT SIGNALIZED INTERSECTIONS UNDER MIXED TRAFFIC CONDITIONS

Author(s):  
ARPITA SAHA ◽  
SATISH CHANDRA ◽  
INDRAJIT GHOSH
2017 ◽  
Vol 143 (8) ◽  
pp. 04017041 ◽  
Author(s):  
Arpita Saha ◽  
Satish Chandra ◽  
Indrajit Ghosh

Transport ◽  
2020 ◽  
Vol 35 (1) ◽  
pp. 48-56
Author(s):  
Sankaran Marisamynathan ◽  
Perumal Vedagiri

The large proportions of pedestrian fatalities led researchers to make the improvements of pedestrian safety at intersections. Thus, this paper proposes a methodology to evaluate crosswalk safety at signalized intersections using Surrogate Safety Measures (SSM) under mixed traffic conditions. The required pedestrian, traffic, and geometric data were extracted based on the videographic survey conducted at signalized intersections in Mumbai (India). Post Encroachment Time (PET) for each pedestrian were segregated into three categories for estimating pedestrian–vehicle interactions and Cumulative Frequency Distribution (CDF) was plotted to calculate the threshold values for each interaction severity level. The Cumulative Logistic Regression (CLR) model was developed to predict the pedestrian mean PET values in the cross-walk at signalized intersections. The proposed model was validated with a new signalized intersection and the results were shown that the proposed PET ranges and model appropriate for Indian mixed traffic conditions. To assess the suitability of model framework, model transferability was carried out with data collected at signalized intersection in Kolkata (India). Finally, this study can be helpful to rank the severity level of pedestrian safety in the crosswalk and improve the existing facilities at signalized intersections.


2020 ◽  
Vol 47 (3) ◽  
pp. 237-247 ◽  
Author(s):  
Satyajit Mondal ◽  
Ankit Gupta

The estimation of the saturation flow is the utmost component for performance evaluation of a signalized intersection. The flow rate estimation procedure includes the analysis of the vehicles headway, vehicles discharge rate, passenger car unit, effective green time and cycle length of the signalling system. This study attempts to exhaustively review the existing literature and its suitability along with the multiple factors affecting the performance of signalized intersection. Different methodological approaches and soft computing techniques used worldwide by the researchers both in developed and developing countries are emphasized. This study also highlights the several influencing factors that have a significant impact on saturation flow value and several methodological approaches to determine the flow value through normalizing the influencing factors, which lead to a better way for planning and designing of a signalized intersection.


Author(s):  
Heng Wei ◽  
Feng Lu ◽  
Gang Hou ◽  
Abi Mogharabi

The adverse effects of bicycles and pedestrians on motor vehicle traffic in at-grade, signalized intersections under mixed-traffic conditions have been observed at several typical intersections in Beijing. Mixed bicycle and motor vehicle traffic is a major characteristic of urban transport in China and has led to serious congestion and capacity reduction in at-grade signalized intersections in urban areas. A method is presented to quantitatively measure nonmotorized effects, and values are recommended for adjusting the model to estimate the capacity of through vehicle lanes. Several temporal segregation solutions to mixed-traffic problems in at-grade signalized intersections are described that have proven cost-effective in several Chinese cities, and suggestions for their application are provided.


Author(s):  
S. Marisamynathan ◽  
P. Vedagiri

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.


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