Speeds of Right-Turning Vehicles at Signalized Intersections during Green or Yellow Phase

2021 ◽  
pp. 036119812110116
Author(s):  
Kay Fitzpatrick ◽  
Michael P. Pratt ◽  
Raul Avelar
Keyword(s):  
Pedestrian Safety ◽  
Operational Efficiency ◽  
Signalized Intersections ◽  
Signalized Intersection ◽  
Radius Of Curvature ◽  
Vehicle Type ◽  
Curvature Equation ◽  
Site Characteristics ◽  
Preceding Vehicle ◽  
Selection Of

The operation and design of signalized intersections involves tradeoffs between operational efficiency and safety for a variety of users, including motorists, pedestrians, and bicyclists. Additionally, the mix of vehicle types in the fleet sometimes requires special considerations. These concerns especially apply to the selection of curb radius at the corners, where right-turning vehicles operate close to pedestrians. Larger curb radii accommodate the swept paths of trucks and allow right turns to occur at higher speeds but may compromise safety and security for pedestrians by increasing the crossing distance and increasing the frequency of higher-speed turns. The authors collected right-turn vehicle speeds at 31 urban signalized intersection approaches in Texas with radii ranging from 15 to 70 ft. The authors calibrated a model to predict right-turn speeds as a function of site characteristics including curb radius, leading headway, vehicle type (car versus truck), maneuver of the preceding vehicle (through versus right turn), and signal indication (yellow or green). The analysis results indicate that right-turn speeds increase slightly with increasing radius, if the preceding vehicle proceeds through (rather than turning right) at the intersection, or if the signal indication is yellow rather than green. The calculated 85th percentile turning speed is generally higher than the assumed speed calculated using the radius of curvature equation. These trends should be considered if the intersection is expected to have notable volumes of pedestrians or trucks, as lower speeds are desirable for pedestrian safety, but larger radii may be necessary to accommodate turning trucks.

scholarly journals PEDESTRIAN SAFETY EVALUATION OF SIGNALIZED INTERSECTIONS USING SURROGATE SAFETY MEASURES

Transport ◽  
2020 ◽  
Vol 35 (1) ◽  
pp. 48-56
Author(s):  
Sankaran Marisamynathan ◽  
Perumal Vedagiri
Keyword(s):  
Safety Evaluation ◽  
Pedestrian Safety ◽  
Signalized Intersections ◽  
Signalized Intersection ◽  
Mixed Traffic ◽  
Model Framework ◽  
Safety Measures ◽  
Severity Level ◽  
Traffic Conditions ◽  
Surrogate Safety Measures

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.

Modeling Capacity of Through Movement at Signalized Intersection Affected by Short Left-Turn Bay under Different Signal Settings

2021 ◽  
pp. 036119812110064
Author(s):  
Zihang Wei ◽  
Yunlong Zhang ◽  
Xiaoyu Guo ◽  
Xin Zhang
Keyword(s):  
Cycle Length ◽  
Signalized Intersections ◽  
Signalized Intersection ◽  
Essential Factor ◽  
Highway Capacity ◽  
Left Turn ◽  
Highway Capacity Manual ◽  
Proposed Model ◽  
Vehicle Demand ◽  
The One

Through movement capacity is an essential factor used to reflect intersection performance, especially for signalized intersections, where a large proportion of vehicle demand is making through movements. Generally, left-turn spillback is considered a key contributor to affect through movement capacity, and blockage to the left-turn bay is known to decrease left-turn capacity. Previous studies have focused primarily on estimating the through movement capacity under a lagging protected only left-turn (lagging POLT) signal setting, as a left-turn spillback is more likely to happen under such a condition. However, previous studies contained assumptions (e.g., omit spillback), or were dedicated to one specific signal setting. Therefore, in this study, through movement capacity models based on probabilistic modeling of spillback and blockage scenarios are established under four different signal settings (i.e., leading protected only left-turn [leading POLT], lagging left-turn, protected plus permitted left-turn, and permitted plus protected left-turn). Through microscopic simulations, the proposed models are validated, and compared with existing capacity models and the one in the Highway Capacity Manual (HCM). The results of the comparisons demonstrate that the proposed models achieved significant advantages over all the other models and obtained high accuracies in all signal settings. Each proposed model for a given signal setting maintains consistent accuracy across various left-turn bay lengths. The proposed models of this study have the potential to serve as useful tools, for practicing transportation engineers, when determining the appropriate length of a left-turn bay with the consideration of spillback and blockage, and the adequate cycle length with a given bay length.

scholarly journals Trajectory Planning Method for Mixed Vehicles Considering Traffic Stability and Fuel Consumption at the Signalized Intersection

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Shan Fang ◽  
Lan Yang ◽  
Tianqi Wang ◽  
Shoucai Jing
Keyword(s):  
Fuel Consumption ◽  
Trajectory Planning ◽  
Signalized Intersections ◽  
Planning Method ◽  
Signalized Intersection ◽  
Driver Model ◽  
Connected Vehicles ◽  
Connected Vehicle ◽  
Traffic Lights ◽  
Trigonometric Model

Traffic lights force vehicles to stop frequently at signalized intersections, which leads to excessive fuel consumption, higher emissions, and travel delays. To address these issues, this study develops a trajectory planning method for mixed vehicles at signalized intersections. First, we use the intelligent driver car-following model to analyze the string stability of traffic flow upstream of the intersection. Second, we propose a mixed-vehicle trajectory planning method based on a trigonometric model that considers prefixed traffic signals. The proposed method employs the proportional-integral-derivative (PID) model controller to simulate the trajectory when connected vehicles (equipped with internet access) follow the optimal advisory speed. Essentially, only connected vehicle trajectories need to be controlled because normal vehicles simply follow the connected vehicles according to the Intelligent Driver Model (IDM). The IDM model aims to minimize traffic oscillation and ensure that all vehicles pass the signalized intersection without stopping. The results of a MATLAB simulation indicate that the proposed method can reduce fuel consumption and NOx, HC, CO2, and CO concentrations by 17%, 22.8%, 17.8%, 17%, and 16.9% respectively when the connected vehicle market penetration is 50 percent.

Effects of adaptive and cooperative adaptive cruise control on the fuel consumption and emissions at the signalized intersection

2018 ◽  
Vol 32 (32) ◽  
pp. 1850396 ◽  
Author(s):  
Hongjun Cui ◽  
Jiangke Xing ◽  
Xia Li ◽  
Minqing Zhu
Keyword(s):  
Fuel Consumption ◽  
Red Light ◽  
Signalized Intersection ◽  
Environmental Benefit ◽  
Cruise Control ◽  
Car Following ◽  
Vehicle Type ◽  
Cooperative Adaptive Cruise Control ◽  
Car Following Model ◽  
Fuel Consumption And Emissions

In this paper, the HDM car-following model, the IIDM car-following model and the IDM car-following model with a constant-acceleration heuristic is utilized to explore the effects of ACC/CACC on the fuel consumption and emissionsat the signalized intersection. Two simulation experiments are studied: (i) one with free road ahead and (ii) the second with a red light 300 m downstream at the second intersection. The numerical results show that CACC vehicle is the best vehicle type among the three vehicle types from the perspective of vehicle’s cumulative fuel consumptions and cumulative exhaust emissions. The results of this paper also suggest a very high environmental benefit of ACC/CACC at little or no cost in infrastructure.

Safety Performance of Rural Curved Corner Intersections with Regional Effects

2021 ◽  
pp. 036119812110444
Author(s):  
Anthony Ingle ◽  
Timothy J. Gates
Keyword(s):  
Negative Binomial ◽  
Signalized Intersections ◽  
Regression Modeling ◽  
Safety Performance ◽  
Radius Of Curvature ◽  
Rural Roads ◽  
Produce Safety ◽  
Regional Effects ◽  
Random Intercept ◽  
Safety Performance Functions

This study evaluates the intersection of rural roads where a curved roadway segment connects the major flow of through traffic from orthogonal directions. A system of up to three intersections in combination can be represented singly by the situation modeled in this paper as a curved corner intersection site. This paper evaluates the application of random intercept negative binomial (NB) regression modeling to produce safety performance functions, and compares the outcome with NB models using fixed regional effects. At curved corner intersections, installing a combined/merged intersection approach near the midpoint of the curve is a potential countermeasure that by comparison with three-leg configurations experienced 20% fewer intersection crashes. A larger radius of curvature along the curved segment at these types of intersections is also very favorable for safety performance. Each 100 ft increase in the radius of a three-leg or four-leg curved corner intersection is estimated to reduce total non-animal crash occurrence by 5% and 7%, respectively. This study can help safety engineers to prioritize the improvement of rural un-signalized intersections.

IDENTIFICATION OF CURVATURE RADIUS FOR CURVED SECTIONS ON FOREST ROADS IN THE PROCESS OF UTILISATION

2021 ◽  
Vol 14(63) (1) ◽  
pp. 47-56
Author(s):  
Ihor RUDKO ◽  
Borys BAKAY ◽  
Abdullah AKAY ◽  
Vasyl BARYLIAK ◽  
Stanislav HORZOV
Keyword(s):  
Technical Information ◽  
Radius Of Curvature ◽  
Curvature Radius ◽  
Forest Roads ◽  
Forest Road ◽  
Advantages And Disadvantages ◽  
Natural Production ◽  
Angle Deviation ◽  
Road Projects ◽  
Selection Of

This article reviews the problem of measuring the actual radius of curvature for curved sections of existing forest roads, as forestry enterprises require reliable technical information about the current conditions of operated transport networks. It was identified that at this moment, a selection of methods are used for measuring the radii of horizontal curved sections of roads, which have certain advantages and disadvantages in specific natural production conditions. For calculating the radius of curvature for auto forest road projects it is recommended to apply the method of measured angles by chord angle deviation, which is sufficiently accurate for engineering purposes and does not require usage of special high-precision equipment and tools.

State-Constrained Optimal Solutions for Safe Eco-Approach and Departure at Signalized Intersections

2020 ◽  
Author(s):  
Jihun Han ◽  
Dominik Karbowski ◽  
Aymeric Rousseau
Keyword(s):  
Analytical Solutions ◽  
Pure State ◽  
Energy Savings ◽  
Minimum Principle ◽  
Optimization Methods ◽  
Signalized Intersections ◽  
Constant Acceleration ◽  
Preceding Vehicle ◽  
Speed Change ◽  
Pass Through

Abstract This paper provides fundamentals of how to energy-efficiently pass through signalized intersections while avoiding any rear-end collisions with leading vehicles. In our previous works [1, 2], analytical solutions with and without second-order pure state constraints imposed by the preceding vehicle were presented; these showed significant energy saving potential for connected and automated vehicles (CAVs) compared to human-driven vehicles. However, these solutions were derived assuming that the desired distance headway policy does not include a speed change over a predictive horizon, and that the preceding vehicle has constant acceleration. We use the desired time headway policy that includes the speed change to define the first-order pure state constraint. We then derive analytical solutions using the direct adjoining method based on Pontryagin’s minimum principle. We also present a novel solver to compute energy-optimal and collision-free state trajectories by accounting for a piecewise constant acceleration of the preceding vehicle without using any numerical optimization methods that require initial guesses. For simple scenarios with one intersection, we analyze how the novel solver allows CAVs to smoothly pass through the signalized intersection and then reach a desired cruising speed. We also use a simulation framework based on high-fidelity powertrain models to validate its effectiveness based on energy savings when driving on real-world urban routes.

Pounce site characteristics of the Western Yellow Robin Eopsaltria griseogularis: the importance of assessing foraging microhabitat

2004 ◽  
Vol 10 (1) ◽  
pp. 21 ◽  
Author(s):  
Jarrad a. Cousin
Keyword(s):  
Leaf Litter ◽  
Substrate Composition ◽  
Habitat Features ◽  
Invertebrate Prey ◽  
Conservation Implications ◽  
Site Characteristics ◽  
Australian Birds ◽  
Close Proximity ◽  
Selection Of

The ground ecosystem represents an important foraging substrate for a large number of Australian birds, including the ground-pouncing Western Yellow Robin Eopsaltria griseogulari. The present study examined the foraging locations of E. griseogularis at the "extreme" microhabitat scale, by measuring ground substrate composition in a 300 mm by 300 mm area surrounding pounce sites, as well as habitat features surrounding pounce sites. Ground substrate composition of pounce sites remained relatively unchanged between seasons, and was characterized by a higher mean percentage of leaf litter and logs when compared to random points. The importance of logs was further emphasized by the closer proximity of logs to pounce sites than to random points. Selection of pounce sites in close proximity to logs and with abundant leaf litter reflects the higher abundance of invertebrate prey associated with these microhabitat attributes, although it may also represent a pounce in close proximity to a log utilized as a perch. During the warmer months of autumn, logs and their associated accumulations of leaf litter, provide sufficient moisture to maintain invertebrate prey, a resource diminished in the surrounding desiccated leaf litter. The conservation implications of these findings are discussed, as is the importance of examining foraging microhabitat in ground-foraging birds.

PEDESTRIAN POTENTIAL RISK WHILE CROSSING AT SIGNALIZED INTERSECTIONS

2016 ◽  
Vol 78 (5-2) ◽  
Author(s):  
Rizati Hamidun ◽  
Nurul Elma Kordi ◽  
Intan Rohani Endut ◽  
Siti Zaharah Ishak ◽  
Mohd Faudzi Mohd Yusof
Keyword(s):  
Risk Factors ◽  
Petri Nets ◽  
Potential Risk ◽  
Signalized Intersections ◽  
Signalized Intersection ◽  
Event Sequence ◽  
Road Section ◽  
Novel Approach ◽  
Pedestrian Accident ◽  
The Hierarchical Structure

Risk of pedestrian while crossing a road section may influence by several factors, including their crossing behaviors which might be difficult to be measured. In this paper, a model using Petri nets is introduced to consider the behavioral factors in measuring pedestrian risk. The crossing scenario of the pedestrian was observed to identify the pedestrian accident event. Sequence of event in pedestrian accident was modeled into Petri Nets elements. The model is designed in the hierarchical structure to consider risk factors related to human behavior, engineering and environment. The analysis of the model provides the numerical value of pedestrian potential risk as they crossed at a signalized intersection. The effect of each factor on the potential risk can be observed through sensitivity analysis.  The use of Petri Nets is a novel approach in predicting pedestrian potential risk through the modeling of pedestrian accident process.

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