Delay Variability at Signalized Intersections

2000 ◽  
Vol 1710 (1) ◽  
pp. 215-221 ◽  
Author(s):  
Liping Fu ◽  
Bruce Hellinga
Keyword(s):  
Analytical Model ◽  
Signalized Intersections ◽  
Signalized Intersection ◽  
Level Of Service ◽  
Cycle Times ◽  
Traffic Conditions ◽  
Cycle Simulation ◽  
Proposed Model ◽  
Delay Variability ◽  
Practical Implications

Delays that individual vehicles may experience at a signalized intersection are usually subject to large variation because of the randomness of traffic arrivals and interruption caused by traffic signal controls. Although such variation may have important implications for the planning, design, and analysis of signal controls, currently no analytical model is available to quantify it. The development of an analytical model for predicting the variance of overall delay is described. The model is constructed on the basis of the delay evolution patterns under two extreme traffic conditions: highly undersaturated and highly oversaturated conditions. A discrete cycle-by-cycle simulation model is used to generate data for calibrating and validating the proposed model. The practical implications of the model are demonstrated through its use in determining optimal cycle times with respect to delay variability and in assessing level of service according to the percentiles of overall delay.

Real-Time Inductive-Signature-Based Level of Service for Signalized Intersections

2002 ◽  
Vol 1802 (1) ◽  
pp. 97-104 ◽  
Author(s):  
Cheol Oh ◽  
Stephen G. Ritchie
Keyword(s):  
Real Time ◽  
Traffic Management ◽  
Signalized Intersections ◽  
Signalized Intersection ◽  
Traffic Information ◽  
Level Of Service ◽  
Self Organizing Map ◽  
Threshold Values ◽  
Support Tool ◽  
Traffic Conditions

The Highway Capacity Manual (HCM) presents a procedure for estimating signalized intersection control delay, which is used to determine level of service (LOS) and to evaluate intersection performance. The HCM is used extensively by traffic engineers. However, it is intended as an offline decision support tool for planning and design. To meet user requirements of advanced traffic management and information systems, new LOS criteria are required for real-time intersection analysis. The objective of this research was to demonstrate a technique for development of such LOS criteria. The study used a new measure of effectiveness, called reidentification delay (RD), derived from analysis of vehicle inductive signatures and reidentification of vehicles traveling through a major signalized intersection in the city of Irvine, California. Two main issues regarding real-time LOS criteria were tackled. The first was how to determine the threshold values partitioning the LOS categories. To provide reliable real-time traffic information, the threshold values should be decided on so that RDs within the same LOS category would represent similar traffic conditions as much as possible. RDs in different LOS categories should also represent dissimilar traffic conditions. The second issue concerned the aggregation interval to use for RD in deriving LOS categories. An investigation of both fixed and cycle-based aggregation intervals was conducted. Several clustering techniques were then employed to derive LOS categories, including k-means, fuzzy, and self-organizing map approaches. The resulting real-time LOS criteria were then determined. The procedures used in this study are readily transferable to other signalized intersections for the derivation of real-time LOS.

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.

Arrival-Based Uniform Delay Model for Oversaturated Signalized Intersections with Poor Progression

2005 ◽  
Vol 1920 (1) ◽  
pp. 86-94
Author(s):  
Rahim F. Benekohal ◽  
Sang-Ock Kim
Keyword(s):  
Signalized Intersections ◽  
Delay Model ◽  
Adjustment Factor ◽  
Highway Capacity ◽  
New Approach ◽  
Highway Capacity Manual ◽  
Traffic Conditions ◽  
Proposed Model ◽  
Uniform Delay ◽  
Control Delays

For oversaturated traffic conditions, the Highway Capacity Manual (HCM) does not apply a progression adjustment factor to the delay model for signalized intersections when there is an initial queue. This causes counterintuitive results in the calculation of delay; for some cases, delay for a nonzero initial queue condition ends up being less than the delay with zero initial queue conditions. Also, for oversaturated traffic conditions, the delay model in the 2000 edition of HCM yields the same uniform delay values for all arrival types when there is an initial queue. This does not seem reasonable because it ignores the effect of platooning on delay. This paper introduces a new approach for computing uniform delay for oversaturated traffic conditions when progression is poor. This approach directly considers the platooning effects in delay and thus eliminates the need to apply a progression adjustment factor. The proposed model is applicable whether there is an initial queue or not. The approach was validated by a comparison of the control delays obtained from a CORSIM simulation to the delays from the proposed model. Validation procedures were conducted on the basis of zero and nonzero initial queue conditions. The proposed approach resulted in more accurate delay values than the HCM model.

scholarly journals An Improvement of Three Leg Signalized Intersections in Duhok City Kurdistan-Iraq

2018 ◽  
Vol 7 (4) ◽  
pp. 87
Author(s):  
Baran R. Omer ◽  
Sherzad W. Khalid
Keyword(s):  
Cycle Time ◽  
Signalized Intersections ◽  
Signalized Intersection ◽  
Level Of Service ◽  
Remarkable Improvement ◽  
Iraqi Kurdistan ◽  
Length Changes ◽  
Time Changes ◽  
Geometric Changes ◽  
The City

Nowadays, number of cars increases in Iraqi Kurdistan. Duhok is one of the Iraqi Kurdistan cities where an enormous increase in the number of cars and population is noticed during the last decade. Roads were been mended according to the 1970s plans where the city was small and number of cars was few. Although the city geographically is located in a hilly area and between two mountains, mending roads is a problem of area. Roads in the mentioned city are quite busy due to the high number of cars, traffic jams can be noticed in every corner of the city especially in signalized intersections. The level of service (LOS) in most of the signalized intersections is F or E. in order to lower the high (LOS), a three leg signalized intersection has been chosen to do an improvement on. During the study the number of the cars (Volume) have been enumerated in all lane groups and the results showed that the (LOS) was E in the intersection. As a result, some solutions have been provided according to the site area and the traffic flow. Solutions were geometric changes, cycle time changes or combination in both geometric and cycle time changes. According to the collected data, it was found that level of service was E for WB and SB and for EB was D. Based on data analysis it was found that LOS has not been improved when only one of the mentioned solutions is applied. In order to have the best improvement, the combination between geometric and cycle time length changes are applied. Analysis showed that there was a remarkable improvement in LOS and changed from E to D.

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.

scholarly journals Analysis of Route Choice for Pedestrian Two-Stage Crossing at a Signalized Intersection

2018 ◽  
Vol 4 (12) ◽  
pp. 2813
Author(s):  
Yongqing Guo ◽  
Xiaoyuan Wang ◽  
Xinqiang Meng ◽  
Yaqi Liu ◽  
Jie Wang
Keyword(s):  
Video Recording ◽  
Route Choice ◽  
Signalized Intersections ◽  
Signalized Intersection ◽  
Limited Attention ◽  
Signal Timing ◽  
Route Choice Behavior ◽  
Proposed Model ◽  
Directional Change ◽  
Pedestrian Infrastructure

Studying pedestrians’ twice-crossing behavior is of great significance to enhance safety and efficiency for pedestrians at signalized intersections. However, limited attention has been paid to analyze and model pedestrians’ behavior patterns of twice crossing. The purpose of this paper is to determine pedestrians' route choices for twice crossing at a signalized intersection, focusing on the waiting position (to cross the street) and walking route. A goal-oriented and time-driven model was proposed to analyze pedestrians’ twice-crossing behavior at signalized intersections, where the two directions have different pedestrian signal timing. A video-recording method was used to collect field data in order to obtain pedestrian preferences in choosing a walking route. It was found that pedestrians in the two directions present different preferences toward walking route, in waiting position, directional change and route type. The results showed that the proposed model is effective in simulating pedestrian route-choice behavior of twice crossing. This research provides a theoretical basis for identifying pedestrian movement intention, optimizing signal timing, and improving pedestrian infrastructure at signalized intersections. 

Analysis on Capacity and LOS of Signalized Intersection in Slight Snowy Weather

2012 ◽  
Vol 209-211 ◽  
pp. 930-933 ◽  
Author(s):  
Chun Xiao Liu ◽  
Guo Zhu Cheng ◽  
Ya Ping Zhang
Keyword(s):  
Signalized Intersections ◽  
Signalized Intersection ◽  
Level Of Service ◽  
Line Method ◽  
Sunny Weather ◽  
American Standard ◽  
Operation Status ◽  
Traffic Operation ◽  
Stop Line

In order to evaluate traffic operation status of signalized intersection in slight snowy weather, it was studied that the influence of slight snow on capacity and level of service (LOS) of signalized intersection. Data of timing, vehicle’s starting loss time, saturated headway of straight vehicle and delay of one signalized intersections in sunny and slight snowy weather were observed by video method. Stop-line method was adopted to calculate the capacity of signalized intersection and LOS was evaluated by American standard. It showed that capacity of signalized intersection decreased by 7% and LOS declined one level in slight snowy weather compared with on sunny weather.

Analytical Model of Passing Events for One-Way Heterogeneous Bicycle Traffic Flows

2018 ◽  
Vol 2672 (36) ◽  
pp. 125-135 ◽  
Author(s):  
Liang Xu ◽  
Meiqi Liu ◽  
Xiang Song ◽  
Sheng Jin
Keyword(s):  
Analytical Model ◽  
Probability Density Functions ◽  
Level Of Service ◽  
Traffic Flows ◽  
Proposed Model ◽  
Different Types ◽  
Bicycle Level Of Service ◽  
Positive Correlations ◽  
Shared Bicycle ◽  
The Relationship

Heterogeneous bicycle traffic flows, consisting of electric bicycles (e-bicycles) and regular bicycles (r-bicycles), have become the main traffic form on shared bicycle routes in China due to the increasing number of e-bicycles. As a result, overtaking occurs frequently among bicycles, which affects cyclists’ safety and perception. This paper presents an analytical model to estimate the number of passing events in heterogeneous bicycle traffic flows. The relationships between passing events and the parameters of the heterogeneous bicycle traffic flow is established in the proposed model. The probability density functions of the speed of r-bicycles and e-bicycles are taken into consideration. The results of the model analysis show that the number of passing events increases with an increase in the flow rate and density. Both a difference in speed between different types of bicycle and the standard deviation of speed of each type of bicycle have positive correlations with the number of passing events. In addition, when the proportion of e-bicycles increases, the number of passing events first increases, and then decreases. The proposed model is calibrated against field data collected in Hangzhou. The results show that the model prediction is consistent with field observations. The model proposed in this paper provides an analytical approach to study the relationship between the characteristics of heterogeneous bicycle traffic flows and the number of passing events. This work can be considered a prerequisite for the development of the bicycle level of service criteria for heterogeneous bicycle flows.

scholarly journals A NEW DELAY PARAMETER DEPENDENT ON VARIABLE ANALYSIS PERIODS AT SIGNALIZED INTERSECTIONS. PART 2: VALIDATION AND APPLICATION

Transport ◽  
2008 ◽  
Vol 23 (2) ◽  
pp. 91-94 ◽  
Author(s):  
Ali Payidar Akgüngör
Keyword(s):  
Linear Regression Analysis ◽  
Signalized Intersections ◽  
Delay Model ◽  
Microscopic Simulation ◽  
Good Relationship ◽  
Traffic Conditions ◽  
Proposed Model ◽  
Calibration And Verification ◽  
Parameter Dependent ◽  
Variable Analysis

The main objective of the present study is to investigate the performance of the proposed model in Part 1 for variable demand, time and oversaturated conditions. To accomplish this objective and test the proposed model, an experimental study was performed. The proposed delay model for oversaturated traffic conditions was calibrated and verified by the TRAF‐NETSIM microscopic simulation program. In the calibration and verification of the proposed model, the simulation study was performed to produce various traffic and time conditions using 48 different scenarios. The delays obtained from the simulations and the proposed model were statistically compared using linear regression analysis. The results indicated that there was a good relationship R2 = 0.989 at 95 % confidence level between the delays generated by the simulations and the delays estimated by the proposed model.

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