scholarly journals Effect of vehicle composition and delay on roundabout capacity under mixed traffic conditions

2016 ◽  
Vol 40 (4) ◽  
pp. 7-14 ◽  
Author(s):  
Dodappaneni Abhigna ◽  
Sindhu Kondreddy ◽  
K. V. R. Ravi Shankar
Keyword(s):  
Simulation Model ◽  
Travel Time ◽  
Andhra Pradesh ◽  
Study Data ◽  
Mixed Traffic ◽  
Capacity Estimation ◽  
Traffic Conditions ◽  
Unsignalized Intersections ◽  
The World ◽  
Estimation Models

Roundabouts are replacing conventional unsignalized intersections in many parts of the world (Polus and Shmueli, 1997). Capacity estimation is necessary for designing a new roundabout, to analyze and improve the existing roundabout facilities. There are several methods to estimate the capacity of the roundabout, but most of them are for homogeneous lane based traffic conditions and not applicable for mixed traffic conditions. This study tries to find out the applicability of the existing methods to mixed traffic conditions, identify the effect of vehicle composition, travel time and delay on capacity. In this study, data was collected from two roundabouts located in Mysore, Karnataka and Rajahmundry, Andhra Pradesh in India. Capacities for both the roundabouts are calculated using the existing methods and compared. VISSIM simulation model has been developed and analyzed for different vehicle compositions scenarios. It was observed that vehicle composition of the traffic influences the roundabout capacity. Since the entry capacity of a roundabout varies significantly with the vehicle composition of the traffic at the roundabout, it is necessary to incorporate this factor into the existing capacity estimation models.

scholarly journals Capacity of Unsignalized Intersections under Mixed Traffic Conditions

2011 ◽  
Vol 16 ◽  
pp. 676-685 ◽  
Author(s):  
Joewono Prasetijo ◽  
Mehdi Hossein Pour ◽  
Seyed Mohammad Reza Ghadiri
Keyword(s):  
Mixed Traffic ◽  
Traffic Conditions ◽  
Unsignalized Intersections

scholarly journals Passenger Car Unit Estimation at Signalized Intersection for Non-lane Based Mixed Traffic Using Microscopic Simulation Model

2017 ◽  
Vol 45 (1) ◽  
pp. 12 ◽  
Author(s):  
Gowri Asaithambi ◽  
Hayjy Sekar Mourie ◽  
Ramaswamy Sivanandan
Keyword(s):  
Simulation Model ◽  
Signalized Intersection ◽  
Accurate Estimation ◽  
Mixed Traffic ◽  
Passenger Car ◽  
Traffic Conditions ◽  
Passenger Car Unit ◽  
Road Width ◽  
On The Road ◽  
Chennai City

In India, traffic on roads is mixed in nature with widely varying static and dynamic characteristics of vehicles. At intersections, vehicles do not follow ordered queue and lane discipline. Different vehicle types occupy different spaces on the road, move at different speeds, and start at different accelerations. The problem of measuring volume of such mixed traffic has been addressed by converting different vehicles categories into equivalent passenger cars and expressing the volume in terms of Passenger Car Unit (PCU) per hour. The accurate estimation of PCU values for different roadway and traffic conditions is essential for better operation and management of roadway facilities. Hence, the objective of the present study is to estimate the PCU values at signalized intersection in mixed traffic and to study the influence of traffic volume, traffic composition and road width on PCU values.For this purpose, a mixed traffic simulation model developed specifically for a signalized intersection was used. The model was calibrated and validated with the traffic data collected from a signalized intersection in Chennai city. Simulation runs were carried out for various combinations of vehicular composition, volume levels and road width. It was observed that presence of heavy vehicles and increase in road width affects the PCU values. The obtained PCU values were statistically checked for accuracy and proven to be satisfied. The PCU values obtained in this study can be used as a guideline for the traffic engineers and practitioners in the design and analysis of signalized intersections where mixed traffic conditions exist.

scholarly journals Optimal Skip-Stop Schedule under Mixed Traffic Conditions for Minimizing Travel Time of Passengers

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Sun Feng ◽  
Zhu Wen-tao ◽  
Ye Ying ◽  
Wang Dian-hai
Keyword(s):  
Travel Time ◽  
Operating Efficiency ◽  
Mixed Traffic ◽  
Optimization Scheme ◽  
Lower Efficiency ◽  
The Road ◽  
Traffic Conditions ◽  
Total Travel Time ◽  
Optimal Coordination ◽  
Urban Bus

Given the lower efficiency resulting from the overload of bus stops, the capacity and travel time of passengers influenced by skip-stop operation are analyzed under mixed traffic conditions, and the travel time models of buses and cars are developed, respectively. This paper proposes an optimization model for designing skip-stop service that can minimize the total travel time for passengers. Genetic algorithm is adopted for finding the optimal coordination of the stopping stations of overall bus lines in an urban bus corridor. In this paper, Tian-Mu-Shan Road of Hangzhou City is taken as an example. Results show that the total travel time of all travelers becomes 7.03 percent shorter after the implementation of skip-stop operation. The optimization scheme can improve the operating efficiency of the road examined.

scholarly journals On the Effects of Various Measures of Performance Selections on Simulation Model Calibration Performance

2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Chen Wang ◽  
Chengcheng Xu
Keyword(s):  
Simulation Model ◽  
Travel Time ◽  
Model Calibration ◽  
Lane Change ◽  
Traffic Conditions ◽  
Average Travel Time ◽  
Traffic Conflicts ◽  
Headway Distribution ◽  
Multicriteria Calibration ◽  
Measures Of Performance

Objective. This paper examines the effects of various measures of performance (MOP) selections on simulation model calibration performance, in terms of reflecting actual traffic conditions and vehicle interactions. Method. Two intersections in Shanghai were selected for simulation model calibration, one for testing and another for validation. Three effective MOPs were utilized, including average travel time (i.e., time passing the intersection), average queue length, and vehicle headway distribution. The counts of three types of traffic conflicts (i.e., crossing, rear-end, and lane change) were used as safety MOPs. Those MOPs, as calibration objectives, were examined and compared. Results. The results of the testing site showed that different effective MOPs had their own advantages: average travel time appeared to be the best in reflecting lane change and rear-end conflicts while headway distribution performed the best consistency between simulated and actual crossing conflicts. Compared to the safety MOPs, average travel time and headway distribution still performed better, in terms of resulting in more similar simulated conflict metrics (e.g., TTC, PET) to actual ones. A multicriteria calibration strategy based on average travel time and headway distribution generally had better performances in reflecting actual traffic conditions and vehicle interactions than using any single effective or safety MOP. Similar results were found for the validation site. Conclusion. To simulate actual traffic conditions and vehicle interactions, multiple effective MOPs could be simultaneously considered for model calibration, instead of using safety MOPs.

scholarly journals Travel Time Prediction under Mixed Traffic Conditions Using RFID and Bluetooth Sensors

2019 ◽  
Vol 48 (3) ◽  
pp. 276-289
Author(s):  
Akhilesh Jayan ◽  
Sasidharan Premakumari Anusha
Keyword(s):  
Travel Time ◽  
Performance Measure ◽  
Mixed Traffic ◽  
Travel Time Prediction ◽  
Time Data ◽  
Traffic Conditions ◽  
Time Prediction ◽  
Match Rate ◽  
Travel Time Data ◽  
Time Information

Travel time information is an integral part in various ITS applications such as Advanced Traveler Information System, Advanced Traffic Management Systems etc. Travel time data can be collected manually or by using advanced sensors. In this study, suitability of Bluetooth and RFID (Radio Frequency Identifier) sensors for data collection under mixed traffic conditions as prevailing in India is explored. Reliability analysis was carried out using Cumulative Frequency Diagrams (CFDs) and buffer time index along with evaluation of penetration rate and match rate of RFID and Bluetooth sensors. Further, travel time of cars for a subsequent week was predicted using the travel time data obtained from RFID sensors for the present week as input in ARIMA modeling method. For predicting the travel time of different vehicle categories, relationships were framed between travel time of different vehicle categories and travel time of cars determined from RFID sensors. The stream travel time was then determined considering the travel time of all vehicle categories. The R-Square and MAPE values were used as performance measure for checking the accuracy of the developed models and were closer to one and lower respectively, indicating the suitability of the RFID sensors for travel time prediction under mixed traffic conditions. The developed estimation schemes can be used as part of travel time information applications in real time Intelligent Transportation System (ITS) implementations.

Capacity of Unsignalized Intersections with Mixed Vehicle Flows

2003 ◽  
Vol 1852 (1) ◽  
pp. 265-270 ◽  
Author(s):  
Wenquan Li ◽  
Wei Wang ◽  
Dazhi Jiang
Keyword(s):  
Traffic Flow ◽  
Field Testing ◽  
Mixed Traffic ◽  
Vehicle Type ◽  
Traffic Conditions ◽  
Unsignalized Intersections ◽  
Capacity Theory ◽  
Capacity Model ◽  
Set Up ◽  
Gap Acceptance Theory

On the basis of gap-acceptance theory, mixed traffic flow composed of two representative vehicle types—heavy and light vehicles—is analyzed with probability theory. A capacity model is set up for an unsignalized intersection in which the minor-stream mixed traffic flows cross m major lanes and the traffic flow headways fit the M3 distribution; it is an extension of minor-lane capacity theory for one vehicle type and one major-stream traffic flow. A more complicated case with minor-stream flow composed of discretionary vehicle types is also considered, and the corresponding formula is given. After field testing in China, the conclusion is drawn that this model is better for analyzing Chinese traffic conditions than are other existing models.

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