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.

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.

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.

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.

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.

Estimation of Saturation Headway in Work Zones on Urban Streets

2017 ◽  
Vol 2615 (1) ◽  
pp. 26-34 ◽  
Author(s):  
Ali Hajbabaie ◽  
SangKey Kim ◽  
Bastian J. Schroeder ◽  
Seyedbehzad Aghdashi ◽  
Nagui M. Rouphail ◽  
...  
Keyword(s):  
Structural Equation Model ◽  
Structural Equation ◽  
Goodness Of Fit ◽  
Equation Model ◽  
Work Zone ◽  
Work Intensity ◽  
Work Zones ◽  
Highway Capacity Manual ◽  
Arterial Streets ◽  
Study Sites

Work zones and lane closures on urban arterials can cause significant disruptions to the traveling public, and methods are increasingly needed to estimate the reductions to saturation flow rates that result from work zones at signalized intersections. A set of statistical models that estimate saturation headways as a function of the presence and configuration of the work zone on signalized arterial streets is presented. More than 10,000 individual vehicular headway observations were collected from video observations in and after work zones at six study sites in North Carolina. Conventional multiple-regression and path-based-regression models (structural equation model) were used to develop the saturation headway models. Three models are provided at different aggregation levels of the collected data with identical work zone configurations. The models developed at cycle-length, 15-min, and full aggregation produced adjusted R-squared values of .3259, .7209, and .895, respectively. The proposed model incorporates the effects of lane configuration, pavement condition, turning percentage from shared lanes, work intensity, and number of closed exclusive turning lanes. Based on path analysis, the structural equation model satisfies all the rule-of-thumb criteria for goodness-of-fit indices. The model uses Highway Capacity Manual default values for turning-vehicle headway effect as its intercept coefficient value.

scholarly journals Highway capacity in work zones – experiences in foreign conditions

2020 ◽  
Vol 66 (3) ◽  
pp. 49-58
Author(s):  
Stefan Andjelkovic ◽  
Vladan Tubić
Keyword(s):  
Traffic Management ◽  
Work Zone ◽  
Level Of Service ◽  
Work Zones ◽  
Highway Capacity ◽  
Traffic Demand ◽  
Traffic Conditions ◽  
Satisfactory Level ◽  
Road Capacity ◽  
Road Work

Traffic management in the highway work zones is a challenge for all traffic engineers. Road work zones are one of the most significant problems for the normal realization of traffic conditions, which can cause various consequences that will greatly reduce capacity and reduce the level of service. On the sections in the work zone, bottlenecks appear, which result in congestion, ie. lead to an imbalance of traffic demand and road capacity. This paper provides an overview of the literature and foreign experiences and ways of regulating traffic in the work zones on the highway. Bearing in mind that we are talking about roads of the highest rank, where are sections with work zones, it is necessary to maintain a satisfactory level of service by applying the concept of regulation that will minimally interfere the normal realization of traffic conditions.

Impact Assessment of Short-Term Work Zones on Intersection Capacity in New York City

2018 ◽  
Vol 2672 (15) ◽  
pp. 1-8
Author(s):  
Nawaf M. Alshabibi ◽  
Elena Prassas
Keyword(s):  
New York ◽  
New York City ◽  
York City ◽  
The United States ◽  
Video Data ◽  
Work Zone ◽  
Unexpected Result ◽  
Work Zones ◽  
Short Term ◽  
Highway Capacity Manual

New York City infrastructure is one of the oldest transportation infrastructures in the United States. Local street construction and short-term work zones are almost continuously planned events that affect the movement of traffic on city streets by requiring the closing of one or more lanes at intersections throughout NYC, and it is important to understand the effect on capacity due to such work. This paper looks at the effect of short-term work zones on the capacity of signalized intersections in New York City. Data was collected at five locations in New York City, both during the work zone and then again after the work zone was removed. Over 25 hours of video data was collected and reduced. It was found that at all locations, the saturation headway was smaller during the work zone compared to after the work zone was removed, that is, the saturation flow rate per lane increased during the work zone. This was an unexpected result. A possible reason for this is the increased traffic pressure that drivers feel when a lane is closed. Thus, although overall approach capacity does decrease because a lane is closed, it did not decrease as much as expected. The field values are then compared with those from two other models: the Highway Capacity Manual model and a model developed by Schroeder et al. It was found that both models underestimate the capacity of the approach.

Sign in / Sign up

Export Citation Format

Share Document