Evaluation and Design of Maximum Green Time Settings for Traffic-Actuated Control

2003 ◽  
Vol 1852 (1) ◽  
pp. 246-255 ◽  
Author(s):  
Jin-Tae Kim ◽  
Kenneth G. Courage
Keyword(s):  
Design Method ◽  
Design Procedure ◽  
Time Estimation ◽  
Estimation Model ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Delay Minimization ◽  
Control Delay ◽  
Average Control ◽  
The One

A study is described that was conducted to develop an improved average green time estimation model for traffic-actuated control and to suggest a maximum green time design method that analytically minimizes intersection control delay. Improvements in the green time estimation model include revisions in the concept of additional queue service time, explicit treatment of right turns in lane groups containing both through and right-turning vehicles, and other improvements that include updates based on recent studies and modifications in the approaches taken for the modeling procedure. The proposed maximum green time design procedure consists of four components: ( a) estimation of the average green time of a traffic-actuated phase, ( b) performance evaluation of the system through the 2000 Highway Capacity Manual (HCM) procedure, ( c) formulation of an overall average control delay minimization problem, and ( d) a search process to find the most efficient set of maximum green time parameters that minimize the average control delay at an intersection. Using simulation as a surrogate for field data collection, it was demonstrated that the proposed average green time estimation models offer better results than the one in the 2000 HCM. In addition, it was suggested that on the basis of the improvements demonstrated in terms of design, the proposed maximum green parameter design procedure represents an advancement of the methodology for analysis of signalized intersections.

Validation of Left-Turn Delay at Two-Way Stop-Controlled Intersections

2000 ◽  
Vol 1710 (1) ◽  
pp. 181-188 ◽  
Author(s):  
Sarah A. Simpson ◽  
Judson S. Matthias
Keyword(s):  
Data Sets ◽  
Highway Capacity ◽  
Left Turn ◽  
Highway Capacity Manual ◽  
Control Delay ◽  
Unsignalized Intersections ◽  
Percent Confidence Level ◽  
The One ◽  
And Control ◽  
Control Delays

Control delay for left-turning vehicles at unsignalized intersections was observed in the field and compared with average control delay calculated from the methodologies presented in the 1997 update of the Highway Capacity Manual (HCM). Unsignalized intersections with two-way left-turn lanes on the major street were observed in the peak and offpeak hours, and control delays were recorded for the one-stage and twostage left-turn processes. Next, the methodologies presented in the HCM were used to calculate the control delay for both processes and compared with the observed data. These comparisons were used as the basis for validation of the HCM methodologies regarding left-turn control delay at unsignalized intersections. From the comparisons, the calculated delay closely corresponds with the observed data, with a total approach volume at the intersection of approximately 2,500 vehicles per hour or less. Once the total approach volume increases above this level, the calculated values rapidly increase and the actual observed control delays gradually increase at a much lower rate. As a result, the observed and calculated delays are different when the intersection handles more than 2,500 approach vehicles in an hour. Statistical analyses were performed on the data to determine if the average observed control delay was related to the calculated control delay. Statistically, the observed control delay and the calculated control delay at the 95 percent confidence level show that the two data sets yield similar results for off-peak conditions. However, during the peak hour, when the total approach volumes are higher, the 95 percent confidence interval yields different results. Hence, the HCM procedures produce, on average, greater control delay estimates than the field observations when the total approach volumes are high.

scholarly journals An Analysis of Unsignalised Intersection Using aaSIDRA Software

2013 ◽  
Vol 4 (2) ◽  
pp. 13-17
Author(s):  
Wan Al-Junaidi Jamil ◽  
Wan Hashim Wan Ibrahim
Keyword(s):  
Variable Parameter ◽  
Traffic Volume ◽  
Level Of Service ◽  
Highway Capacity ◽  
Peak Period ◽  
Factors Affecting ◽  
Highway Capacity Manual ◽  
Control Delay ◽  
Critical Gap ◽  
Average Control

This thesis discusses about the use of Akcelik & Associates Signalised & Unsignalised Intersection Design and Research Aid (aaSIDRA Intersection) Software in the analysis of unsignalised intersection in Sarawak, Malaysia. aaSIDRA Intersection software was used to analyse the data which were manually obtained through traffic volume study carried out at the two junctions during the morning peak period and also helps in producing the capacity and Level of Service of the intersection. Four parameters were analysed in this thesis: critical gap, follow-up time, proportion of heavy vehicles or motorcycles and total number of vehicles for each of the approaches of the intersection. Referring to the Highway Capacity Manual (HCM), these variable parameter values are determined and then the expected output of the aaSidra being used in the analysis of this study are average control delay, existing level of service, and capacity of the junction. Fixed values to be input into SIDRA Intersection are obtained from the traffic volume study. The input influences the value for the average control delay which assists in determining the Level of Service of the intersection. These output values are highly influenced by the respective input values. All factors analysed under four parameters to determine the level of service of the two junctions were contributing equally and correlates with each other and there was not one that exceeds the other factor. The critical factors affecting the level of service are critical gap and traffic volume.

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 Travel Time Estimation on Urban Street Segment

2018 ◽  
Vol 30 (1) ◽  
pp. 115-120 ◽  
Author(s):  
Jelena Kajalić ◽  
Nikola Čelar ◽  
Stamenka Stanković
Keyword(s):  
Travel Time ◽  
Time Estimation ◽  
Travel Speed ◽  
Degree Of Saturation ◽  
Level Of Service ◽  
Travel Time Estimation ◽  
Highway Capacity ◽  
Local Conditions ◽  
Highway Capacity Manual ◽  
Urban Streets

Level of service (LOS) is used as the main indicator of transport quality on urban roads and it is estimated based on the travel speed. The main objective of this study is to determine which of the existing models for travel speed calculation is most suitable for local conditions. The study uses actual data gathered in travel time survey on urban streets, recorded by applying second by second GPS data. The survey is limited to traffic flow in saturated conditions. The RMSE method (Root Mean Square Error) is used for research results comparison with relevant models: Akcelik, HCM (Highway Capacity Manual), Singapore model and modified BPR (the Bureau of Public Roads) function (Dowling - Skabardonis). The lowest deviation in local conditions for urban streets with standardized intersection distance (400-500 m) is demonstrated by Akcelik model. However, for streets with lower signal density (<1 signal/km) the correlation between speed and degree of saturation is best presented by HCM and Singapore model. According to test results, Akcelik model was adopted for travel speed estimation which can be the basis for determining the level of service in urban streets with standardized intersection distance and coordinated signal timing under local conditions.

Operational Analysis of a Single-Lane Roundabout with a Mix of Driverless Vehicles

2017 ◽  
Vol 2615 (1) ◽  
pp. 123-131
Author(s):  
Liang Shi ◽  
Panos D. Prevedouros
Keyword(s):  
Sensitivity Analyses ◽  
Gap Acceptance ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Control Delay ◽  
Operational Analysis ◽  
Traffic Composition ◽  
Acceptance Model ◽  
Traffic Operation

Driverless cars (DLCs) are vehicles capable of managing several driving tasks by themselves under different degrees of human intervention. DLCs are able to maintain shorter headways in entering a roundabout and circulating in the roundabout. The Highway Capacity Manual (HCM) provides a regression-based gap acceptance model for estimating the capacity of roundabouts. The gap acceptance model captures driver behavior, which is characterized by headways. As automotive manufacturers and technology companies develop driverless capabilities for roadway vehicles, DLCs at various traffic compositions will likely have different effects on the traffic operation of roundabouts. This paper presents the operational analysis for a single-lane roundabout with driverless vehicles under different traffic compositions. Considering the uncertainty of the technological capabilities and the legal and behavioral acceptability of DLCs, sensitivity analyses were conducted. The simulation results for one sample case study show that when the roundabout operates at a Level of Service B (LOS B) or better, DLCs will not have an effect on either the capacity or the control delay. A reduction in control delay will occur when DLCs are set with shorter headways (as assumed for the connected DLC) under low traffic composition (1% to 10%) on a single-lane roundabout operating near capacity. When the share is below 1%, the effect of DLCs is very small. When the LOS of the roundabout approaches E, more reduction in delay is expected when the portion of DLCs in traffic increases.

scholarly journals Simulasi Manajemen dan Rekayasa Lalulintas Untuk Meningkatkan Kinerja Simpang Tiga Tak Bersinyal Pada Jalan Jatiraya – Kahuripan Nirwana Kabupaten Sidoarjo (Management and Traffic Engineering Simulation to Improve The Unsignalised Intersection Performance on Jalan Jatiraya – Kahuripan Nirwana Kabupaten Sidoarjo)

2016 ◽  
Vol 1 (01) ◽  
pp. 32
Author(s):  
Kurnia Hadi Putra ◽  
Faisal Rosih Alfanan
Keyword(s):  
Traffic Engineering ◽  
Traffic Congestion ◽  
Degree Of Saturation ◽  
Primary Data ◽  
Level Of Service ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Toll Road ◽  
Commercial Area ◽  
The One

AbstractUnsignalised 3-way intersection at Jati Raya – Kahuripan Nirvana streets is an area with high traffic congestion. It caused by the increasing of vehicle volume at rush hour. In addition, the surrounded area of the intersection is a commercial area with a dense population and the intersection is also the main access to the toll road. To deal with these conditions, management and traffic engineering need to be done. The method of field surveys is conducted to obtain primary data and the existing condition. All the traffic data is obtained from the number of vehicles passing through the intersection for four days (27-30 May 2016). Then, all the data is recapitulated and calculated using the formula of Indonesian Highway Capacity Manual 1997. As the result, it can be concluded that the 3-way intersection at Jati Raya – Kahuripan Nirvana has the degree of saturation (DS) 1.23. This value is far from the one suggested by MKJI 1997 for the unsignalized 3-way intersection, i.e. DS = 0.85. Therefore, management and traffic engineering are conducted to overcome these conditions. The fourth alternative shows the DS 0,51 with Level of Service C.Keywords: Unsignalised Intersection, Degree of Saturation, Management and Traffic Engineering AbstrakSimpang tiga tak bersinyal pada jalan Jati Raya – Kahuripan Nirwana merupakan daerah yang sering mengalami kemacetan. Hal ini disebabkan oleh pertumbuhan lalu lintas yang cukup tinggi, selain itu disekitar simpang merupakan daerah komersil, pemukiman penduduk dan akses menuju jalan tol. Dalam mengatasi permasalahan pada simpang digunakan manajemen dan rekayasa lalu lintas. Metode yang digunakan adalah metode survei lapangan untuk mendapatkan data primer dan kondisi eksisting. Data lalu lintas diperoleh dari jumlah kendaraan yang melintasi simpang selama empat hari (27-30 Mei 2016). Kemudian data tersebut diolah dengan perhitungan Manual Kapasitas Jalan Indonesia (MKJI) 1997. Dari hasil analisis data dapat disimpulkan bahwa simpang jalan Jati Raya – Kahuripan Nirwana memiliki nilai Derajat Kejenuhan (DS) = 1,23 dengan Level Of Service LOS (F) . Nilai itu jauh dari nilai yang disarankan oleh MKJI 1997 untuk simpang tak bersinyal yaitu DS = 0,85. Oleh karena itu dilakukan beberapa alternatif solusi manajemen dan rekayasa lalu lintas. Dalam mengatasi kemacetan diambil alternatif solusi yang menghasilkan derajat kejenuhan (DS) paling kecil dengan nilai = 0,51 dengan Level Of Service LOS (C) yang terjadi pada alternatif empat.Kata kunci: Simpang tak bersinyal, Derajat Kejenuhan, Manajemen rekayasa lalulintas

Evaluating Weaving Section Designs Using INTEGRATION

1996 ◽  
Vol 1555 (1) ◽  
pp. 33-41 ◽  
Author(s):  
J. Stewart ◽  
M. Baker ◽  
M. Van Aerde
Keyword(s):  
Design Procedure ◽  
Critical Factor ◽  
Core Area ◽  
Design Solution ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
The Core ◽  
Current Design ◽  
Core Areas ◽  
Levels Of Service

The current design procedure shown in Calculation 6 of the Highway Capacity Manual (HCM) requires an exhaustive analysis of a family of possible solutions. The design is selected on the basis of minimum speeds of weaving and nonweaving vehicles for different levels of service. In this paper the use of the INTEGRATION modeling tool to evaluate the same family of possible solutions is examined. Because INTEGRATION has the ability to determine volumes in addition to speeds, it was used to select the design solution based on the ratio of demand volume to capacity. Both procedures determined that five-lane Type B weaving sections greater than 610 m (2,000 ft) in length would provide level-of-service C for the origin-destination demand pattern found in Example Calculation 6 in Chapter 4 of the HCM. Analysis of the design results also showed that the number of lanes in the core area was the most critical factor in determining weaving section capacity. The length of the core area was also found to have an impact but was less important as core length increased. Finally, the type of weaving section was found to have the least impact on capacity, especially at core areas longer than 305 m (1,000 ft).

scholarly journals ON THE OPTIMAL STRUT-AND-TIE MODELS AND DESIGN APPROACH FOR THE CABLE-PYLON ANCHORAGE ZONE

2019 ◽  
Vol 25 (6) ◽  
pp. 576-586 ◽  
Author(s):  
Nannan Cui ◽  
Shiping Huang
Keyword(s):  
Strain Energy ◽  
Design Method ◽  
Design Procedure ◽  
Optimization Techniques ◽  
Strut And Tie ◽  
Cable Stayed Bridge ◽  
D Region ◽  
Minimum Strain Energy ◽  
The One ◽  
Application Scope

The cable-pylon anchorage zone is a typical D-region in a cable-stayed bridge, for which there has been no uniform simplified design method until now. In this paper, based on the extensive statistics of actual projects, topology optimization techniques and principle of minimum strain energy, two precise strut-and-tie models for the cable-pylon anchorage zone are proposed, which can clearly reveal the load-transmitting mechanism of the anchorage zone. Th e explicit geometric parameters of the strut-and-tie models are derived; thus, the designers can directly use these models. A simple design procedure to deploy prestressing tendons in the anchorage zone is also introduced, whose effectiveness and convenience are demonstrated by two design examples. A new design named the “one-way prestressing tendons PC cable-pylon” is also discussed regarding its application scope.

Detailed Observations of Saturation Headways and Start-Up Lost Times

2002 ◽  
Vol 1802 (1) ◽  
pp. 44-53 ◽  
Author(s):  
Honglong Li ◽  
Panos D. Prevedouros
Keyword(s):  
Field Measurement ◽  
Queue Length ◽  
Dominant Role ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Traffic Conditions ◽  
Start Up ◽  
Lost Time ◽  
The One ◽  
Saturation Flow

The analyses conducted in this research were based on three methodologies for the field measurement of saturation headways. The first method (M1), the one on which most past studies were based, measured the characteristics of Vehicles 4 to 12 in a standing queue. M2, the method found in the Highway Capacity Manual (HCM), counted all vehicles in a standing queue, regardless of queue length. M3 included arrivals that joined the standing queue as long as vehicles were up to 140 ft from the stop line. This study focused on one approach of a high-design intersection with heavy, random arrivals. The large number of observations and the practically ideal traffic conditions enabled the acquisition of several statistically significant results on saturation flow ( s), start-up lost time (SULT), and start-up response time (SRT): ( a) when long queues are present, the typical field measurement of s based on the first 12 vehicles is an overestimate of s for through vehicles and an underestimate of s for protected left-turning vehicles; ( b) the type of movement had a more dominant role in determining s than the level of saturation (or queue length); ( c) SRT displayed a bigger variation than headways— the left-turning movement had a significantly shorter SRT than the through movement did; and ( d) much higher SULTs were estimated in this study compared with those in the HCM.

scholarly journals Measuring Control Delays at Signalized Intersections in Mixed Traffic Conditions

2021 ◽  
Vol 29 (3) ◽  
pp. 31-40
Author(s):  
R. Sushmitha ◽  
K. V. R. Ravishankar
Keyword(s):  
Linear Model ◽  
Mobile Application ◽  
Research Work ◽  
Mixed Traffic ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Control Delay ◽  
Traffic Conditions ◽  
Non Linear ◽  
Control Delays

Abstract Control delay is the key performance indicator of a signalized intersection that defines the level of service. Several models have been developed in previous research work for estimating control delays, but many of them were based on homogeneous traffic conditions. In the present study, an Open Street Map (OSM) tracker mobile application was used to measure control delays from the field. A non-linear model was developed in the present study for estimating control delays in mixed traffic conditions using a MATLAB fitting tool. The field delay is compared with the developed non-linear model delay along with the Indian Highway Capacity manual (INDO HCM) and Highway Capacity Manual (HCM) models. The control delay estimated using the model developed in the present study shows a close relation with the field delay obtained using an OSM tracker when compared to that obtained using the INDO HCM and HCM models. Therefore, the OSM tracker mobile application can be used as a field control delay measuring technique.

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