Queue Analysis at Work Zones from Field-Collected Data

2021 ◽  
pp. 036119812110252
Author(s):  
Julius Codjoe ◽  
Raju Thapa ◽  
Elisabeta Mitran
Keyword(s):  
Flow Rate ◽  
Discharge Rate ◽  
Time Of Day ◽  
Work Zone ◽  
Speed Ratio ◽  
Work Zones ◽  
Highway Capacity ◽  
Local Data ◽  
Highway Capacity Manual ◽  
Annual Average Daily Traffic

Estimation of the capacity of work zones is vital to manage the possibility of traffic flows exceeding capacity and resulting in unbearable queues during work zone lane closures. A plethora of research papers have studied several ways to estimate work zone capacity, with the Highway Capacity Manual (HCM) having its own methodology to estimate capacity based on various site characteristics. However, HCM always recommends validating its model with local data to reflect the actual driving behavior of the region. This study considered work zone capacity as a function of queue discharge rate (QDR), defined as the 15-min average flow rate immediately after breakdown, also known as postbreakdown flow rate. By collecting data from 10 different work zones within the state of Louisiana, the study estimated QDR and its corresponding duration at breakdowns. An average QDR of 1,664 pcphpl and an associated queue of 120 min average duration was found. Analysis of variance showed that average QDRs across all sites were not significantly different. The QDR prediction model revealed that a closed right lane and a work zone on linear roadways significantly increased the discharge rate. However, the presence of nearby exit ramps, daytime scenarios, and an increase in the speed ratio and truck percentages were found to decrease the discharge rate. A separate model for the duration of queue or breakdown found the time of day, change in the speed ratio, presence of entry ramp, location of work zones, and annual average daily traffic of the roadway to be significant variables.

Survey of Work Zone Practices and Validation of Highway Capacity Manual Work Zone Capacity Model

2021 ◽  
pp. 036119812110145
Author(s):  
Raju Thapa ◽  
Julius Codjoe ◽  
Amanua Osafo
Keyword(s):  
The United States ◽  
The State ◽  
Work Zone ◽  
Work Zones ◽  
Highway Capacity ◽  
Local Data ◽  
Highway Capacity Manual ◽  
Capacity Model ◽  
Minimum Capacity ◽  
Lane Closures

Capacity at work zones is one of the major factors affecting queueing at work zones. Different states within the United States use their own methodology in determining work zone capacities and when to implement lane closures at work zones. The objective of this study was two-fold: first, to provide a synthesis of work zone lane closure procedures practiced by the various Departments of Transportation (DOTs) nationwide; and secondly, to validate the Highway Capacity Manual 6th edition’s (HCM 6) work zone capacity model using field-collected data in the state of Louisiana. The first objective was met by administering a survey to DOTs nationwide. The survey revealed that half of the states that responded to the survey require minimum capacity for short-term work zone lane closures, with minimum capacity ranging from 1100 to 1900 passenger cars per hour per lane. In addition, most of the states reported implementing consistent policies across various district offices. The survey findings provide a good source of information on queue analysis and work zone lane closure policies adopted across different DOTs. The second objective was met by collecting traffic flow data from 10 work zone sites within the state of Louisiana and validating the capacity model in the HCM 6. Results showed the HCM 6 model slightly overestimating the average field-observed capacity by 6%. In the absence of local data, the HCM 6 model provides a great tool to estimate work zone capacities in Louisiana.

scholarly journals Predicting Freeway Work Zone Capacity Distribution Based on Logistic Speed-Density Models

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Chaoru Lu ◽  
Jing Dong ◽  
Anuj Sharma ◽  
Tingting Huang ◽  
Skylar Knickerbocker
Keyword(s):  
Prediction Method ◽  
Volume Density ◽  
Lifetime Distribution ◽  
Work Zone ◽  
Work Zones ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Stop And Go ◽  
Stochastic Capacity ◽  
Density Relationship

Speed-volume-density relationship and capacity are key elements in modelling traffic operations, designing roadways, and evaluating facility performance. This paper uses a modified five-parameter logistic model to describe the speed-density relationship. The calibrated speed-density models show that the stop-and-go speed (Vb) and shape parameters (θ1 and θ2) are similar for work zones and the nonwork zone site. Accordingly, an operational capacity prediction method is proposed. To demonstrate the effectiveness of the proposed method, the predicted operational capacities are compared with the field data, Highway Capacity Manual method, the output of WorkZoneQ software, and the ensemble tree approach under different work zone scenarios. Furthermore, a lifetime distribution prediction framework for stochastic capacity of work zones is proposed. The predicted lifetime distribution can well capture the tendency of the observed work zone capacities.

New Insights into Freeway Capacity at Work Zones: Empirical Case Study

2000 ◽  
Vol 1710 (1) ◽  
pp. 154-160 ◽  
Author(s):  
Ahmed Al-Kaisy ◽  
Miao Zhou ◽  
Fred Hall
Keyword(s):  
Field Data ◽  
Weather Conditions ◽  
Work Zone ◽  
Work Zones ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Congested Traffic ◽  
Extensive Field ◽  
Freeway Capacity ◽  
Lane Closures

A construction project in Ontario, Canada, provided the opportunity to use field data to investigate freeway capacity at long-term lane closures due to rehabilitation work. Data from two lane closures at the same construction site (eastbound and westbound) were examined. The site is located on the Gardiner Expressway in the southern part of downtown Toronto. Data were collected during 4 days, totaling around 53 h of congested traffic operations. Results showed significant variation in freeway capacity in the work zones. Despite this variation, average capacity values are reasonably close to the corresponding values provided in the Highway Capacity Manual. Four intervening variables were investigated; all exhibited significant but different effects on freeway work-zone capacity. These variables included temporal variation (which is thought to relate to driver characteristics), grade, day of week, and weather conditions. The results confirmed the pressing need for more extensive field data that will allow better identification of the effect of various control variables on work-zone capacity.

Saturation Flow and Capacity of Shared Lanes: Comparative Evaluation of Estimation Methods

1996 ◽  
Vol 1555 (1) ◽  
pp. 50-58
Author(s):  
G. A. Glannopoulos ◽  
Muhammad A. S. Mustafa
Keyword(s):  
Flow Rate ◽  
Comparative Evaluation ◽  
Field Measurements ◽  
Estimation Methods ◽  
Highway Capacity ◽  
Operational Conditions ◽  
Highway Capacity Manual ◽  
Traffic Volumes ◽  
Saturation Flow Rate ◽  
Saturation Flow

The operation of shared lanes, especially in the case of permitted phasing control, is still considered a complicated task and one for which many procedures and methods have been introduced. Dealt with here is the complexity when left- or right-turn movements or both are made during the unsaturated part of the opposing traffic flow. Three main methods used for estimating the shared lane's saturation flow rate and capacity values—that used in the 1985 Highway Capacity Manual (HCM) and the Australian Road Research Board (ARRB) and the Canadian methods—were analyzed and evaluated. The methodology for the comparative evaluation was based on two main approaches. In the first approach, example 1 of Chapter 9 of the HCM was used as a case study in which left through and left through right shared lanes exist in permitted phase control. In this case several computer runs were performed using the programs SIDRA and SINTRAL to estimate saturation flow and capacity values of the shared lanes opposed by different traffic volumes of the conflicting movements. Results of this approach showed that the 1985 HCM and ARRB methods are fairly close in estimating saturation flow and capacity, whereas the Canadian method gave considerably different results. Analysis showed that the sensitivity of the Canadian method to estimate saturation flow rates of the shared lane in cases of different levels of opposing traffic was an average of 10 times higher than the average of the two other methods, which were very close in their estimation of levels of opposing traffic volumes. In the second approach, field measurements of saturation flow rate values of shared lanes at different locations and operational conditions were compared with the values estimated by the three methods under the same conditions. Results, based on field observations, revealed that the Canadian method estimates of saturation flow were always lower than the measured values. At low saturation flow values, HCM estimates were slightly higher than the observed values; however, at higher saturation flow rate values. HCM estimates closely matched the observed ones. The ARRB method estimates were quite close to the observed saturation flow values under all of the different conditions considered in the field observation task.

Lane-by-Lane Analysis Framework for Conducting Highway Capacity Analyses at Freeway Segments

2019 ◽  
Vol 2673 (8) ◽  
pp. 523-535
Author(s):  
Fabio Sasahara ◽  
Lily Elefteriadou ◽  
Shen Dong
Keyword(s):  
Flow Distribution ◽  
Time Of Day ◽  
Heavy Vehicles ◽  
Highway Capacity ◽  
Operational Conditions ◽  
Highway Capacity Manual ◽  
Loop Detectors ◽  
Speed Flow ◽  
Flow Speeds ◽  
The Usa

The Highway Capacity Manual (HCM) methodology for freeway systems yields average speed values for each segment and does not consider lane-by-lane flow and operational conditions. However, flows are not equally distributed between lanes. In congested conditions and particularly when spillback occurs, flows and traffic conditions vary widely. For example, the rightmost lane may be blocked while the leftmost lane is free-flowing. The purpose of this research is to develop a model for estimating lane-by-lane speeds and flows under various freeway designs and demands. Speed and flow data from loop detectors at several locations around the USA were collected, totaling 531,000 observations aggregated in 15-min intervals. The results show that lane flow distribution is highly dependent on the segment total flow, with different patterns for 4-, 6-, and 8-lane segments. The percentage of heavy vehicles, presence of nearby ramps, day of week, and time of day also affect the distribution of flow among freeway lanes. Theoretical lane-by-lane speed-flow curves were developed and the results were compared with field data. Results showed that lane-by-lane speeds can be estimated accurately, as long as inputs for capacity and free-flow speeds can be provided for each lane in the segment.

Identification of Operational Design Domain for Autonomous Truck Mounted Attenuator System on Multilane Highways

2021 ◽  
pp. 036119812110615
Author(s):  
Qing Tang ◽  
Xianbiao Hu ◽  
Hong Yang
Keyword(s):  
Discharge Rate ◽  
Design Domain ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Flow Models ◽  
Effective Discharge ◽  
Discharge Rates ◽  
Operational Design ◽  
Traffic Flow Models ◽  
Key Indicators

The Autonomous Truck Mounted Attenuator (ATMA) vehicle system is a technology that leverages connected and automated vehicle (CAV) capabilities for maintenance of transportation infrastructure. Promoted by FHWA and state departments of transportation (DOTs), it is a niche CAV application in leader–follower style, intended to remove DOT workers from the following maintenance truck, to reduce fatalities in work zones. Because practicable guidance for deployment of this technology is largely missing in MUTCD, state DOTs have been making their own deployment criteria. In this manuscript, we focus on the operational design domain (ODD) problem—under what traffic conditions should ATMA be deployed. Modeling efforts are first focused on the derivation of an effective discharge rate that can be associated with a moving bottleneck caused by slow-moving ATMA vehicles on a multilane highway. Then, based on the demand input and discharge rates, microscopic traffic flow models calculate vehicle delay and density, which the Highway Capacity Manual (HCM) suggests are key indicators of a multilane highway’s level of service (LOS). In this way, the linkage between AADT and LOS is analytically established. NGSIM data is used for the model validation and shows that the developed model correctly captures the effective discharge rate discount caused by moving bottlenecks. The modeling results demonstrate that roadway performance is sensitive to the K factor and D factor, as well as the operating speed of ATMA and, if LOS = C is a desirable design objective, a good AADT threshold to use would be around 40,000 vehicles per day.

Effect of Lane Width on Speeds of Cars and Heavy Vehicles in Work Zones

2005 ◽  
Vol 1920 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Madhav V. Chitturi ◽  
Rahim F. Benekohal
Keyword(s):  
Flow Speed ◽  
Heavy Vehicles ◽  
Work Zones ◽  
Passenger Cars ◽  
Highway Capacity ◽  
Speed Reduction ◽  
Interstate Highways ◽  
Highway Capacity Manual ◽  
Traffic Stream ◽  
Lane Width

Traffic data were collected from 11 work zones on Interstate highways in Illinois in which one of the two lanes was open. The reductions in free-flow speed (FFS) due to narrow lanes and lateral clearances in work zones were studied. It was found that the reductions in FFSs of vehicles in work zones because of narrow lanes were higher than the reductions given in the Highway Capacity Manual for basic freeway sections. The data also showed that the narrower the lane was, the greater the speed reduction was. The data showed that the FFSs of heavy vehicles were statistically lower than the FFSs of passenger cars, even though the speed limit was the same for both types of vehicles. In addition, the reduction in the FFSs of heavy vehicles was greater than the reduction in the FFSs of passenger cars. This greater reduction in the speed of heavy vehicles affected the performance of the traffic stream in work zones. Thus, it should be considered in the computation of the passenger car equivalence for heavy vehicles. It is recommended that 10, 7, 4.4, and 2.1 mph be used for speed reduction in work zones for lane widths of 10, 10.5, 11, and 11.5 ft, respectively.

User costs at the work zone

2001 ◽  
Vol 28 (4) ◽  
pp. 747-751 ◽  
Author(s):  
Fazil T Najafi ◽  
Roberto Soares
Keyword(s):  
Traffic Control ◽  
Technical Note ◽  
Work Zone ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
User Costs ◽  
Delay Models ◽  
Control Devices ◽  
Traffic Control Devices

The objective of this technical note is to discuss the implications related to evaluating work zone user costs. It discusses the work zone dilemma existing among the agency, users, and contractors, and presents different strategies that have been conducted to minimize delay and maximize the number of vehicles that can travel safely throughout the work zone. It further discusses the implication of using five of the most used tools in the process of evaluating the work zone: (i) the Manual on Uniform Traffic Control Devices (MUTCD); (ii) the Highway Capacity Manual (HCM); (iii) computerized software; (iv) delay models; and (v) work zone user costs models.Key words: work zone, user costs, HCM, MUTCD, accident, delay, delay costs.

A Method for Determining Length of Freeway Work Zone Based on Classification of Service Level

2013 ◽  
Vol 779-780 ◽  
pp. 491-497 ◽  
Author(s):  
Ke Man Wu ◽  
Lian De Zhong
Keyword(s):  
Flow Simulation ◽  
Service Level ◽  
Work Zone ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Traffic Flow Simulation ◽  
Design Speed ◽  
Traffic Composition ◽  
The Relationship

based on the relationship between speed and density according to the classification criteria of freeway service level when the design speed is 80km/h in Highway capacity manual, the method of microscopic traffic flow simulation supported by VISSIM software is adopted, such that, in the situation the capacity and desired speed are guaranteed to be consistent with the reality, the proposed values of the length of work zone under different traffic composition and traffic volume are given in the condition that a 2-way-8-lane freeway is half closed for construction with 2-way-4-lane being left open for traffic.

Freeway Planning Methodology

2003 ◽  
Vol 1852 (1) ◽  
pp. 63-68
Author(s):  
Elena Shenk Prassas ◽  
Douglas McLeod ◽  
Gina Bonyani
Keyword(s):  
Rural Areas ◽  
Travel Speed ◽  
Average Density ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Annual Average Daily Traffic ◽  
Engineering Level ◽  
Florida Department ◽  
Planning Methodology ◽  
Parameter Values

A major new chapter of the Highway Capacity Manual (HCM) 2000 is on freeway facilities. It is a detailed operational methodology that combines analyses of basic freeway segments, weaving areas, off-ramp areas, and on-ramp areas. However, the new chapter does not contain guidance or examples for planning or preliminary engineering applications. To meet its numerous needs, Florida Department of Transportation engineers wanted to develop a freeway facility application that extends the HCM for generalized planning and preliminary engineering purposes but is not inconsistent with HCM 2000. Such a methodology was developed, documented, made into an executable software program called FREEPLAN, and is now being implemented throughout the state. The methodology is firmly based on HCM detailed analysis procedures but has assumptions and defaults that allow planners and engineers to use it effectively. At a generalized planning level, the basic construct was to provide tables of design volumes, v, and annual average daily traffic that could be achieved for various levels of service and freeway configurations for the default parameter values. At a preliminary engineering level, specific freeway facility inputs are used to determine v/c ratio, average travel speed, average density, and level-of-service grades. The initial results of applying the Florida freeway planning methodology to actual Florida data were outstanding in both urbanized and rural areas.

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