Pedestrian Crossing Sight Distance: Lateral Clearance Guidelines for Roadways

A turbo roundabout uses spiral circulatory roads for effectively counteracting the problems faced in modern multilane roundabouts. First developed in 1996, the turbo roundabout has an advantage over the conventional roundabout regarding capacity and safety. Turbo roundabouts are still in the developing phase in North America, but even in the European subcontinent where they exist in large numbers, reliable analytical studies on the critical parameters of roundabout visibility are lacking. Visibility (sight distance) helps to shape the geometry of the intersection and aids in safety. This paper presents the mathematical characteristics of the intersection geometry and intersection sight distance (ISD) of the turbo roundabout. Mathematical formulas are presented for the sight distance from the approaching vehicle to the conflicting-entering and circulating vehicles. The maximum lateral clearances to the conflicting vehicles are derived using mathematical optimization. The developed analytical method is verified graphically using AutoCAD. To assist in practical applications, design aids for the maximum lateral clearance are presented. The presented method and design aids should aid in promoting safety at turbo roundabouts.

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Reliability of stopping and decision sight distance at roundabouts

10.32920/ryerson.14652636.v1 ◽

2021 ◽

Author(s):

Jafar Faizi

Keyword(s):

Probabilistic Method ◽

Design Parameters ◽

Second Moment ◽

First Order ◽

State Highway ◽

Sight Distance ◽

Design Variables ◽

First Order Second Moment ◽

Stopping Sight Distance ◽

Lateral Clearance

The existing Stopping Sight Distance (SSD) and Decision Sight Distance (DSD) design methods for roundabouts are deterministic. This means that all of the design variables are predetermined, fixed values. This study presents a probabilistic method for the determination of SSD and DSD at roundabouts based on the equation recommended by the American Association of State Highway and Transportation Officials (AASHTO 2011). The reliability-based method considers all design parameters as random variables. Three types of SSD (SSD for approaches, SSD along the circulatory lane, and SSD for exiting vehicles to the pedestrian crosswalk) were considered in this study. DSD was considered for roundabout approaches. The First-Order Second-Moment and Advanced First-Order Second-Moment methods were used to model SSD and DSD. Once the required SSD and DSD were determined, the lateral clearance requirements at every point of the roundabout were calculated.

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Reliability Analysis of Intersection Sight Distance at Roundabouts

Infrastructures ◽

10.3390/infrastructures5080067 ◽

2020 ◽

Vol 5 (8) ◽

pp. 67 ◽

Cited By ~ 1

Author(s):

Said M. Easa ◽

Yang Ma ◽

Shixu Liu ◽

Yanqun Yang ◽

Shriniwas Arkatkar

Keyword(s):

Sight Distance ◽

Reliability Method ◽

First Order Second Moment ◽

Design Values ◽

Mean And Variance ◽

Coefficients Of Variations ◽

The Mean ◽

Lateral Clearance ◽

Second Moment Method ◽

Special Case

This paper presents a reliability-based method for the design of intersection sight distance (ISD) at traffic roundabouts using the linear and nonlinear deceleration profiles of the entry vehicles. The reliability method is based on the first-order second moment method which is simple and relatively accurate compared with advanced methods. The nonlinear deceleration profile includes a shape parameter that produces the linear profile as a special case. Deterministic and reliability-based formulas for the required ISD for an approaching vehicle are developed for the entry vehicle on the left and the vehicle on the circulating roadway. Then, the design values of the ISD legs, applicable to any type of roundabout, are presented for different probabilities of non-compliance (Pnc) and different coefficients of variations. For the special case of single-lane symmetrical roundabouts, which have a well-defined geometry, the lateral clearance needs are established. The sensitivity analysis shows that ISD is very sensitive to both the mean and variance of the critical headway. The results show that the deterministic method results in ISD values that correspond to a very small Pnc, indicating that the method is very conservative. The proposed method, which provides flexibility in selecting ISD for any given Pnc, should be of interest to highway designers and practitioners to promote roundabout safety.

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Reliability of stopping and decision sight distance at roundabouts

10.32920/ryerson.14652636 ◽

2021 ◽

Author(s):

Jafar Faizi

Keyword(s):

Probabilistic Method ◽

Design Parameters ◽

Second Moment ◽

First Order ◽

State Highway ◽

Sight Distance ◽

Design Variables ◽

First Order Second Moment ◽

Stopping Sight Distance ◽

Lateral Clearance

The existing Stopping Sight Distance (SSD) and Decision Sight Distance (DSD) design methods for roundabouts are deterministic. This means that all of the design variables are predetermined, fixed values. This study presents a probabilistic method for the determination of SSD and DSD at roundabouts based on the equation recommended by the American Association of State Highway and Transportation Officials (AASHTO 2011). The reliability-based method considers all design parameters as random variables. Three types of SSD (SSD for approaches, SSD along the circulatory lane, and SSD for exiting vehicles to the pedestrian crosswalk) were considered in this study. DSD was considered for roundabout approaches. The First-Order Second-Moment and Advanced First-Order Second-Moment methods were used to model SSD and DSD. Once the required SSD and DSD were determined, the lateral clearance requirements at every point of the roundabout were calculated.

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Reliability analysis of pedestrian crossing sight distance

10.32920/ryerson.14653059.v1 ◽

2021 ◽

Author(s):

Sadia Karim

Keyword(s):

Reaction Time ◽

Reliability Analysis ◽

Coefficient Of Variation ◽

Safety Margin ◽

Vehicle Speed ◽

Major Road ◽

First Order ◽

Sight Distance ◽

First Order Second Moment ◽

Pedestrian Crossing

The main objective of this study was to calculate the required sight distance corresponding to the various probabilities of failure by considering two methods of reliability analysis. This paper presents a probabilistic approach based on such random variables as major road vehicle speed, walking speed, pedestrian observation-reaction time, the length of the crossing unit, pedestrian setback from the nearest curb of the major road. A safety margin is defined as the difference between available and required sight distances. By using the first-order second moment (FOSM) method, relationships for the mean and standard deviation of the safety margin were developed. The advance first-order second-moment (AFOSM) was also used to find the supplied sight distance corresponding to reliability index. Comparison of two methods was done. Obtained results from the two methods were almost similar to a low coefficient of variation. Different design graphs were developed to calculate the required sight distance at a different coefficient of variation corresponding to the probability of failure and different vehicle design. Sensitivity analysis was performed to obtain the most sensitive variable to the pedestrian crossing sight distance. It was found that vehicle speed is more sensitive to required sight distance and perception-reaction time has least effect on supplied (required) sight distance. Application of these methods is presented with two examples. This probabilistic method is valuable in designing pedestrian crossing sight distance for any preferred reliability level.

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Reliability analysis of pedestrian crossing sight distance

10.32920/ryerson.14653059 ◽

2021 ◽

Author(s):

Sadia Karim

Keyword(s):

Reaction Time ◽

Reliability Analysis ◽

Coefficient Of Variation ◽

Safety Margin ◽

Vehicle Speed ◽

Major Road ◽

First Order ◽

Sight Distance ◽

First Order Second Moment ◽

Pedestrian Crossing

The main objective of this study was to calculate the required sight distance corresponding to the various probabilities of failure by considering two methods of reliability analysis. This paper presents a probabilistic approach based on such random variables as major road vehicle speed, walking speed, pedestrian observation-reaction time, the length of the crossing unit, pedestrian setback from the nearest curb of the major road. A safety margin is defined as the difference between available and required sight distances. By using the first-order second moment (FOSM) method, relationships for the mean and standard deviation of the safety margin were developed. The advance first-order second-moment (AFOSM) was also used to find the supplied sight distance corresponding to reliability index. Comparison of two methods was done. Obtained results from the two methods were almost similar to a low coefficient of variation. Different design graphs were developed to calculate the required sight distance at a different coefficient of variation corresponding to the probability of failure and different vehicle design. Sensitivity analysis was performed to obtain the most sensitive variable to the pedestrian crossing sight distance. It was found that vehicle speed is more sensitive to required sight distance and perception-reaction time has least effect on supplied (required) sight distance. Application of these methods is presented with two examples. This probabilistic method is valuable in designing pedestrian crossing sight distance for any preferred reliability level.

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ENSURING THE PEDESTRIAN’S SAFETY DESIGN OF URBAN STREET CROSSWALKS

Биосферная совместимость: человек, регион, технологии ◽

10.21869/23-11-1518-2019-26-2-103-110 ◽

2019 ◽

pp. 103-110

Author(s):

Dmitriy Nemchinov

Keyword(s):

Traffic Flow ◽

Minimum Distance ◽

Travel Speed ◽

Vehicle Speed ◽

Urban Street ◽

Safety Design ◽

Positive Practices ◽

Time Required ◽

Pedestrian Crossing ◽

The City

The article presents an analysis of positive practices for ensuring the safety of pedestrians at the inter-section of the city streets carriageway, as well as a description of some innovations of regulatory and tech-nical documents, including an increased number of cases when a safety island can be arranged at a pedestri-an crossing. requirements for providing visibility at a pedestrian crossing to determine the minimum distance of visibility at a pedestrian crossing based on the time required pedestrians for crossing the roadway, recommended options for using ground unregulated pedestrian crossings on trapezoidal artificial irregularities according to GOST R 52605; traffic flow) and Z-shaped (also in the direction of the traffic flow), the requirements for the size of the securi-ty island have been established to allow put bicycle inside of safety island, a recommended set of measures to reduce the vehicle speed and describes the types of activities and describes a method of their application, describes methods zones device with reduced travel speed - residential and school zones, set requirements for turboroundabouts and methods of their design.

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Impacts of mobile phone distractions on pedestrian crossing behavior at signalized intersections: An observational study in China

Advances in Mechanical Engineering ◽

10.1177/1687814019841838 ◽

2019 ◽

Vol 11 (4) ◽

pp. 168781401984183 ◽

Cited By ~ 2

Author(s):

Zhuping Zhou ◽

Sixian Liu ◽

Wenxin Xu ◽

Ziyuan Pu ◽

Shuichao Zhang ◽

...

Keyword(s):

Observational Study ◽

Mobile Phone ◽

Signalized Intersections ◽

Pedestrian Crossing

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Effect of pedestrian traffic light on traffic flow accompany with pedestrian crossing

Physica A Statistical Mechanics and its Applications ◽

10.1016/j.physa.2021.126059 ◽

2021 ◽

pp. 126059

Author(s):

Yanhong Wang ◽

Chong Zhang ◽

Pengbin Ji ◽

Tianning Si ◽

Zhenzhen Zhang

Keyword(s):

Traffic Flow ◽

Traffic Light ◽

Pedestrian Traffic ◽

Pedestrian Crossing

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Analysis and Prediction of Pedestrians’ Violation Behavior at the Intersection Based on a Markov Chain

Sustainability ◽

10.3390/su13105690 ◽

2021 ◽

Vol 13 (10) ◽

pp. 5690

Author(s):

Chengyuan Mao ◽

Lewen Bao ◽

Shengde Yang ◽

Wenjiao Xu ◽

Qin Wang

Keyword(s):

Markov Chain ◽

Markov Chain Model ◽

Warning System ◽

Demographic Characteristics ◽

Chain Model ◽

Behavior Prediction ◽

Road Geometry ◽

Using Data ◽

Pedestrian Crossing ◽

Prediction Approach

Pedestrian violations pose a danger to themselves and other road users. Most previous studies predict pedestrian violation behaviors based only on pedestrians’ demographic characteristics. In practice, in addition to demographic characteristics, other factors may also impact pedestrian violation behaviors. Therefore, this study aims to predict pedestrian crossing violations based on pedestrian attributes, traffic conditions, road geometry, and environmental conditions. Data on the pedestrian crossing, both in compliance and in violation, were collected from 10 signalized intersections in the city of Jinhua, China. We propose an illegal pedestrian crossing behavior prediction approach that consists of a logistic regression model and a Markov Chain model. The former calculates the likelihood that the first pedestrian who decides to cross the intersection illegally within each signal cycle, while the latter computes the probability that the subsequent pedestrians who decides to follow the violation. The proposed approach was validated using data gathered from an additional signalized intersection in Jinhua city. The results show that the proposed approach has a robust ability in pedestrian violation behavior prediction. The findings can provide theoretical references for pedestrian signal timing, crossing facility optimization, and warning system design.

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