Review and Evaluation of Methods for Analyzing Capacity at Signalized Intersections

1997 ◽  
Vol 1572 (1) ◽  
pp. 160-166 ◽  
Author(s):  
Catherine C. McGhee ◽  
Eugene D. Arnold
Keyword(s):  
Simulation Model ◽  
Traffic Engineering ◽  
Queue Length ◽  
Computer Programs ◽  
Signalized Intersections ◽  
Capacity Analysis ◽  
Highway Capacity ◽  
Operational Characteristics ◽  
Study Results ◽  
Departments Of Transportation

Capacity analysis is a critical activity in traffic engineering and planning divisions of state departments of transportation across the nation. The Highway Capacity Manual (HCM) provides a methodology for capacity analysis that is commonly accepted and often required by state departments of transportation. The variety of computer programs that exist to aid transportation professionals in conducting capacity analyses has led to questions regarding the best methods to use under various conditions. Several computer programs other than the Highway Capacity Software (HCS) that are commonly used in evaluating capacity at signalized intersections were evaluated to determine which ones provide acceptable results. The results obtained from a simulation model were also evaluated to determine whether the model could be used to determine the operational characteristics of signalized intersections. The study results, although based on limited data, provided valuable information about the programs evaluated. HCS, SIGNAL94, HCM/Cinema, and the simulation model TRAF-NETSIM are all acceptable for capacity analysis at isolated intersections. SIGNAL94, HCM/Cinema, and TRAF-NETSIM provide reasonable estimates of queue length at isolated intersections. However, at isolated intersections where congested, oversaturated conditions exist, TRAF-NETSIM provides more accurate measures of delay and queue length. At nonisolated intersections where queueing and spill-back are potential problems, simulation analysis with TRAF-NETSIM is recommended instead of capacity analysis to determine the operational characteristics of the corridor.

Variations in Capacity at Signalized Intersections with Different Area Types

2000 ◽  
Vol 1710 (1) ◽  
pp. 199-204 ◽  
Author(s):  
Xuewen Le ◽  
Jian Lu ◽  
Edward A. Mierzejewski ◽  
Yanhu Zhou
Keyword(s):  
Signalized Intersections ◽  
Capacity Analysis ◽  
Adjustment Factor ◽  
Highway Capacity ◽  
Left Turn ◽  
Highway Capacity Manual ◽  
Central Florida ◽  
Start Up ◽  
Study Results ◽  
Lost Time

The capacity analysis procedure for signalized intersections included in the Highway Capacity Manual (HCM) needs to consider the area type of a given intersection. The area-type adjustment factor used in the procedure is based on conclusions from a limited number of studies. In addition, the procedure for using an area-type adjustment factor is not well defined in the HCM. A study undertaken in central Florida to study the effects of four different area types on the capacity of signalized intersections is summarized. These four area types include recreational, business, residential, and shopping. Study results indicated that differences in saturation headways among different area types were significant. The saturation headways observed in recreational areas were significantly higher than those in other areas for both left-turn and through movements. The through-movement saturation headways obtained in residential, shopping, and business areas were not significantly different. This study resulted in a new area-type adjustment factor of 0.92 for recreational areas, whereas the factor is 1.00 for other areas. Results in this study also indicated that the differences in start-up lost time among different area types were not significantly different. In addition, according to the results of the analysis, 75 percent of the yellow interval in undersaturated conditions and 35 percent of the yellow interval in oversaturated conditions were found to be unused and considered clearance lost time.

Validation of Generalized Delay Model for Oversaturated Conditions

1997 ◽  
Vol 1572 (1) ◽  
pp. 122-130 ◽  
Author(s):  
Roelof J. Engelbrecht ◽  
Daniel B. Fambro ◽  
Nagui M. Rouphail ◽  
Aladdin A. Barkawi
Keyword(s):  
Simulation Model ◽  
Close Agreement ◽  
Signalized Intersections ◽  
Delay Model ◽  
Traffic Operations ◽  
Microscopic Simulation ◽  
Highway Capacity ◽  
Traffic Demand ◽  
Highway Capacity Manual ◽  
The U.S

With today’s ever-increasing traffic demand, more and more signalized intersections are experiencing congestion for longer periods of time. To better quantify oversaturated conditions, it is necessary to accurately estimate oversaturation delay. The generalized delay model, proposed for inclusion in the next update of the U.S. Highway Capacity Manual (HCM), is introduced here. The generalized delay model differs from the model in the 1994 edition of the HCM as it is sensitive to the duration of the analysis period and is not restricted to degrees of saturation less than 1.2. The TRAF-NETSIM microscopic simulation model was used to verify the generalized delay equation for oversaturated conditions. A simulation model was used, because it is extremely difficult to measure oversaturated delay in the field. The study was designed to cover as much of the domain of oversaturated traffic operations as possible. The variability in simulated delays was investigated, and an equation was developed to predict the standard deviation of oversaturated delay estimates. It was found that delays estimated by the proposed generalized delay model are in close agreement with those simulated by TRAF-NETSIM. On average, simulated delays are overestimated slightly, but the error is small compared with actual delays. The proposed generalized delay model is expected to provide a good estimate of actual oversaturation delays that occur in the field.

scholarly journals Delay-based Passenger Car Equivalent at Signalized Intersections in Iran

2017 ◽  
Vol 29 (2) ◽  
pp. 135-142 ◽  
Author(s):  
Habibollah Nassiri ◽  
Sara Tabatabaie ◽  
Sina Sahebi
Keyword(s):  
Signalized Intersections ◽  
Simulation Software ◽  
Heavy Vehicles ◽  
Passenger Cars ◽  
Highway Capacity ◽  
Passenger Car ◽  
Highway Capacity Manual ◽  
Operational Characteristics ◽  
Passenger Car Equivalent ◽  
Traffic Operation

Due to their different sizes and operational characteristics, vehicles other than passenger cars have a different influence on traffic operations especially at intersections. The passenger car equivalent (PCE) is the parameter that shows how many passenger cars must be substituted for a specific heavy vehicle to represent its influence on traffic operation. PCE is commonly estimated using headway-based methods that consider the excess headway utilized by heavy vehicles. In this research, the PCE was estimated based on the delay parameter at three signalized intersections in Tehran, Iran. The data collected were traffic volume, travel time for each movement, signalization, and geometric design information. These data were analysed and three different models, one for each intersection, were constructed and calibrated using TRAF-NETSIM simulation software for unsaturated traffic conditions. PCE was estimated under different scenarios and the number of approach movements at each intersection. The results showed that for approaches with only one movement, PCE varies from 1.1 to 1.65. Similarly, for approaches with two and three movements, the PCE varies from 1.07 to 1.99 and from 0.76 to 3.6, respectively. In addition, a general model was developed for predicting PCE for intersections with all of the movements considered. The results obtained from this model showed that the average PCE of 1.5 is similar to the value recommended by the HCM (Highway Capacity Manual) 1985. However, the predicted PCE value of 1.9 for saturated threshold is closer to the PCE value of 2 which was recommended by the HCM 2000 and HCM 2010.

Development of Driver Population Factors for Capacity Analysis of Signalized Intersections

2000 ◽  
Vol 1710 (1) ◽  
pp. 239-245 ◽  
Author(s):  
Yanhu Zhou ◽  
Jian John Lu ◽  
Edward A. Mierzejewski ◽  
Xuewen Le
Keyword(s):  
Flow Rate ◽  
Signalized Intersections ◽  
Capacity Analysis ◽  
Study Results ◽  
Adjustment Factors ◽  
Saturation Flow Rate ◽  
High Level ◽  
Saturation Flow ◽  
The Impact ◽  
Population Adjustment

In the Highway Capacity Manual (HCM), driver population factors are included to adjust for the impact of nonlocal drivers on freeway capacity. There are no such factors in the HCM to account for the possible change of capacity at signalized intersections caused by unfamiliar drivers in the traffic stream. The results obtained from a research study to develop driver population adjustment factors for capacity analysis of signalized intersections are summarized. Detailed procedures for quantifying driver population adjustment factors are presented. The factors were derived on the basis of data collected in Hillsborough, Pinellas, Orange, and Osceola counties in Florida. Study results indicated that nonlocal drivers had a significant impact on the saturation flow rate. When a signalized intersection was identified with a high level of nonlocal drivers, the saturation flow rate as well as the capacity could be reduced by 19 percent, which corresponded to a driver population factor as low as 0.81.

scholarly journals Analysis of a Signalized Intersection with Dynamic Use of the Left-Turn Lane for Opposite through Traffic

2020 ◽  
Vol 12 (18) ◽  
pp. 7530
Author(s):  
Yongtao Zheng ◽  
Xuedong Hua ◽  
Wei Wang ◽  
Jialiang Xiao ◽  
Dongya Li
Keyword(s):  
Simulation Model ◽  
Queue Length ◽  
Field Data ◽  
Signalized Intersections ◽  
Signalized Intersection ◽  
Simulation Environment ◽  
Average Delay ◽  
Left Turn ◽  
Environment Parameters ◽  
Simulation Scheme

For signalized intersections with a quantitative imbalance between the approach and exit lanes, this study proposes a method for the dynamic use of the left-turn lane for opposite through traffic to improve the efficiency of the signalized intersection. The complete scheme of this method mainly consists of three parts: the location routes of the dynamic lane, the temporal scheme, and the spatial scheme. To demonstrate the effectiveness of this method, a simulation scheme comparing the intersection with and without the dynamic lane is designed using VISSIM. The parameters of the simulation model, including the traffic simulation environment parameters and built-in VISSIM models, are calibrated by the field data collected from an intersection in Nanjing, P. R. China. The results of the simulation indicate that this method decreases the average delay and average queue length of the intersection effectively for the intersection with a quantitative imbalance between the approach and exit lanes under the conditions of different through volumes or left-turn ratios. The maxima were 46.9% (average delay) and 68.3% (average queue length) for all situations. Lastly, some suggestions are presented for the application of this method.

Queue Length at Signalized Intersections from Red-Time Formula and the Highway Capacity Manual Compared with Field Data

2017 ◽  
Vol 2615 (1) ◽  
pp. 159-168 ◽  
Author(s):  
Xueying Liu ◽  
Rahim (Ray) F. Benekohal ◽  
Mohammed Abdul Rawoof Shaik
Keyword(s):  
Correction Factor ◽  
Queue Length ◽  
Field Data ◽  
Signalized Intersections ◽  
Highway Capacity ◽  
Significant Discrepancy ◽  
Peak Period ◽  
Highway Capacity Manual ◽  
Lower Volume ◽  
Queue Lengths

This study compared the Highway Capacity Manual 2010 (HCM 2010) procedure (the procedure in HCM 2016 is the same) and the red-time formula (RTF) estimations of the back-of-queue with field data results. The comparisons were made for the 50th and 95th percentile field queue lengths at four signalized intersections along a corridor in one off-peak period and a.m., noon, and p.m. peak periods. For the 50th percentile queue length, the HCM estimates had significant differences from the field data in 52% of the cases (major and minor street cases combined); in 93% of which the HCM overestimated the queue length and in 7% it underestimated the queue length. For the major street, in 28% of the cases the HCM significantly overestimated the queue length on average by 66%, and in 4% of the cases the HCM significantly underestimated on average by 42%. For minor streets, in 70% of the cases the HCM significantly overestimated the queue length on average by 44%, and in 5% of the cases it significantly underestimated on average by 20%. To lower the number of cases with significant discrepancy and to balance the frequency of overestimation and underestimation, a multiplicative correction factor of 0.93 for the major street and 0.78 for the minor streets could be applied to the HCM estimates. For the 95th percentile queue length comparison, in general the HCM presented a better estimation than the RTF. And for minor streets, the RTF tends to overestimate the queue length at higher-volume approaches, while it underestimates at lower-volume approaches. But on a major street with heavier traffic than the minor, such a trend is not clear.

SIMULATION OF A SEA CARGO PORT AS A QUEUING SYSTEM IN ANYLOGIC

2020 ◽  
Vol 4 (26) ◽  
pp. 59-66
Author(s):  
A. G. Morozkov ◽  
◽  
M. R. Yazvenko ◽  
Keyword(s):  
Simulation Model ◽  
Key Words ◽  
Simulation Modeling ◽  
Queue Length ◽  
System Simulation ◽  
Queuing System ◽  
System Model ◽  
System Capacity ◽  
Mathematical Solution ◽  
Structure Simulation

The article presents simplified queuing system model of freight marine port. The article discusses the basic elements of queuing system, its mathematical solution and structure. Simulation model was created using AnyLogic to analyze an effect of system capacity on queue length. The results were analyzed and the solution for queue optimization was proposed. Key words: queuing system, simulation modeling, AnyLogic, marine port, servers, queue.

scholarly journals Study on improving three-dimensional dynamic simulation model and equation of flexible fabric

2019 ◽  
Vol 11 (6) ◽  
pp. 168781401985284
Author(s):  
Meiliang Wang ◽  
Mingjun Wang ◽  
Xiaobo Li
Keyword(s):  
Simulation Model ◽  
Dynamic Simulation ◽  
Material Properties ◽  
Three Dimensional ◽  
Equation Solving ◽  
Study Results ◽  
Essential Properties ◽  
Dynamic Simulation Model ◽  
Novel Model ◽  
Simulation Equation

The use of the traditional fabric simulation model evidently shows that it cannot accurately reflect the material properties of the real fabric. This is against the background that the simulation result is artificial or an imitation, which leads to a low simulation equation. In order to solve such problems from occurring, there is need for a novel model that is designed to enhance the essential properties required for a flexible fabric, the simulation effect of the fabric, and the efficiency of simulation equation solving. Therefore, the improvement study results will offer a meaningful and practical understanding within the field of garment automation design, three-dimensional animation, virtual fitting to mention but a few.

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 Use of simulation model for measurement of MilkRun system performance

2019 ◽  
Vol 9 (1) ◽  
pp. 600-605 ◽  
Author(s):  
Gabriel Fedorko ◽  
Martin Vasil ◽  
Michaela Bartosova
Keyword(s):  
Simulation Model ◽  
Production Systems ◽  
Operational Performance ◽  
Transport Systems ◽  
Indirect Methods ◽  
Operational Characteristics ◽  
Wide Range ◽  
Effective Operation ◽  
And Performance ◽  
Plant Simulation

AbstractIntra-plant transport systems within their operation directly impact on the performance of production systems. For their effective operation, it is, therefore, necessary to realize evaluation of operational performance and effectivity. For the realization of this type of evaluation, in addition to a wide range of sensors that can be difficult for installation and operation, we can also use indirect methods that are equally able to provide reliable operational characteristics. Indirect analytical methods are presented above all by the approach which is based on the use of simulation methods. The method of computer simulation provides a wide range of options for the evaluation of efficiency and performance. The paper describes the use of a simulation model created in the program Tecnomatix Plant Simulation for analyzing the supply of production workplaces within the MilkRun system.

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