Showing papers by "Satish Chandra published in 2016"

Effect of traffic composition on capacity of multilane highways

Abstract: Mixed traffic has always been a major concern in all studies related to estimation of capacity of a highway in developing nations like India. The problem of mixed traffic is generally circumvented by making use of passenger car equivalency factors for different categories of vehicles and converting them into equivalent number of Passenger Cars Units (PCU). However, capacity is also required in terms of vehicles per hour, particularly for quick estimation of volume-to-capacity ratio on a highway. The present study investigates the effect of traffic mix on capacity of four-lane, six-lane divided highways in India. All vehicles on a highway are divided into five categories namely standard car, big car, heavy vehicle, motorized three-wheelers and motorized two-wheelers, and effect of each vehicle type on capacity of the highway is evaluated. The VISSIM software is calibrated and used to generate the traffic operations based on field data using capacity as the measure of performance. Speed-flow curves are developed to find simulated capacity values for different combinations of standard car and one of the remaining four types of vehicles in the traffic stream. The results are finally combined to propose the generalized equations to determine capacity when all or few of the five categories of vehicles are simultaneously present on a highway.

Conceptual Approach for Estimating Dynamic Passenger Car Units on Urban Arterial Roads by Using Simultaneous Equations

Abstract: This study demonstrates that passenger car unit (PCU) values for a vehicle are not static and vary with traffic volume and composition. Data collected at eight urban arterial roads in India were analyzed to explain the dynamic nature of the PCU factor. All vehicles in the traffic stream were divided into five categories, and simultaneous equations were developed to determine the speed of a vehicle type from information on traffic volume and composition. These equations were used to show the variation in PCU values with traffic volume and composition on a road. The change in PCU values was explained on the basis of the relative interaction of vehicle type in the traffic stream at different volume levels. A proposed range of PCU values for big vehicles was from 1.47 to 1.65 for big cars and for heavy vehicles from 5.51 to 6.54, respectively, when their proportions in the mix remained within an observed range in the field. Similarly, a range of PCU values for motorized three-wheelers of 0.99 to 1.01 and a se...

Determination of Passenger-Car Units on Two-Lane Intercity Highways under Heterogeneous Traffic Conditions

Abstract: The introduction of the passenger car unit (PCU) concept by the 1965 edition of the Highway Capacity Manual (HCM) enabled researchers around the world to deal with mixed traffic flow. Though some researchers have tried to show the dynamic nature of PCU factors, most of the studies in the world, as well as the latest standards being followed, still provide static PCU values for various types of vehicle categories. The present study demonstrates the dynamic nature of PCU factors on two-lane intercity highways under highly heterogeneous traffic composition. They are estimated based on speed and size of vehicle type in the traffic stream with respect to a standard passenger car. Simultaneous equations are formulated to calculate the speeds of different types of vehicles for a given traffic composition and traffic volume on the road, which lead to the determination of PCU factors. While many plots are made to describe the effect of traffic composition and volume on PCU of a vehicle type, it is felt tha...

Modeling the critical position of U-turning vehicles at uncontrolled median openings

Abstract: The present study provides a methodology for identification of the conflict zone between a turning vehicle and on-coming vehicles at uncontrolled median openings on urban roads under mixed traffic conditions. Data for turning movements of different types of vehicles were collected at 13 median openings on 6-lane roads and 8 median openings on 4-lane roads in different cities of India. These data are analyzed statistically and it was found that the critical position (path of the outer wheel) of a vehicle is influenced by the vehicle size and the road width. In the case of 6-lane roads, the critical position of turning vehicle may follow a unimodal or bimodal distribution depending upon the proportion of motorized two-wheelers (2-W) in the turning volume. On 4-lane roads, the gamma distribution was found to fit the placement data at all the eight sections. A simple model is proposed to identify the boundary of the conflict zone at median openings. The geometrical augmentation required at the median opening in order to avoid the conflict between turning vehicles and through traffic in the opposing median lane is also suggested.

Warm mix asphalt investigation on public roads -a review

Abstract: Warm mix asphalt has been introduced in Europe in 1997 and in the United State 2002. The first trail of warm mix asphalt has done publically in Europe in 1999, in U.S.A 2004 and in India 2009. Most of countries like Germany, Norway, France, U.S.A, Canada, China, Korea, South Africa, India and Brazil have successfully used the WMA construction on public roads after successful laboratory test. The WMA is more success in U.S.A compare to European countries (EAPA, 2014). The main goal of WMA is to produce the bituminous mixtures with similar strength, durability and performance characteristics as HMA substantially reduced the mixing and compaction temperature. This study focus on history and development of warm mix asphalt in different countries including advantage and disadvantage of warm mix asphalt. This paper also reviews the warm mix asphalt in India.

Merging process of U-turns at uncontrolled median openings under mixed traffic conditions

Abstract: At an uncontrolled median opening, the limited priority situation and the high degree of heterogeneity in traffic stream make the merging manoeuvre of U-turning vehicles very much complex. This study is an attempt to understand this merging manoeuvre. The different types of merging manoeuvres have been identified in the field and accordingly classified into different categories. Depending upon the number of vehicles that can merge all together into the opposing through traffic by accepting a single gap, the merging has been classified into two types: single entry merging and multiple entry merging. On the other hand, based on the situation of priority of movement, the merging process is divided into another two categories: ideal merging and forced merging. More explicitly, the ideal merging is split into free merging and Swift Merging (SM). In addition, the forced entry merging is categorized into Gradual Merging (GM) and Aggressive Merging (AM). Time distance diagrams for different types of merging are presented for their better understanding. Field data collected at seven median openings located on various 6-lane divided urban roads are used to analyse different types of merging in a mixed traffic situation. All vehicles plying on the road are divided into 5 categories such as car, motorized two-wheeler (2-W), motorized three-wheeler (3-W), Sports Utility Vehicle (SUV), and Light Commercial Vehicle (LCV) and the merging behaviour of these categories of vehicles have been studied. The effect of influencing parameters like opposing traffic volume and delay on merging are investigated. Mathematical relations are developed between Merging Time (MT) of a vehicle type and the opposing traffic volume. To address the effect of Service Delay (SD) on the MT of a vehicle, models are proposed between SD and MT for all the five categories of vehicles. The two types of merging; gradual and swift are prominently observed in field. The time required by different categories of vehicles for these two merging at various traffic volume levels are determined. Finally, two-tailed t-test is conducted to see if the MT for the two different types of merging is statistically different. First published online 26 October 2016

Conflicting volume for U-turns at uncontrolled median openings

Abstract: This paper proposes a practical approach to estimate the conflicting traffic volume caused by U-turns at uncontrolled median openings under mixed traffic conditions. Data were collected at 21 median openings on multi-lane divided roads in India (i.e. 13 on six-lane and eight on four-lane). The road width at the median opening is divided into three parts: zone of severe conflict, zone of safety and unaffected zone based on the placement of the left wheel of U-turning vehicles (left-hand drive rule followed in India). The first two zones together are considered as the conflicting zone for calculating the conflicting traffic. The proportion of opposing through traffic within the conflicting zone is considered as the conflicting traffic volume for U-turns. The conflicting volume at all the sections is estimated based on placement of through traffic across the width of the road and it is found to be dependent on the size of the U-turning vehicle. An equation is suggested to calculate the conflicting traffic ba...

Effect of Countdown Timers on Traffic Characteristics and Driver Behaviors at Signalized Intersections

Abstract: Signal countdown timers are being installed adjacent to the traffic signal heads at major signalized intersections in India. These timers display the seconds remaining for a particular signal phase to the drivers and expected to help them with a better decision making process. Conflicting results have been obtained by researchers across the world regarding timers’ effect on the efficiency and safety potential at signalized intersection locations. Therefore, the present study tried to assess the influence of timers on several traffic characteristics and driver behaviors by collecting data from three signalized intersection locations in New Delhi. Total of three different approaches were studied both in the presence and absence of timers. It was found that the timers did not influence saturation flow, but they helped reducing the start-up lost time significantly. Percentage of cycles with red light violations (RLVs) and mean RLV per RLV cycle increased in the presence of timer during the last 10 seconds of red phase, but different effect was observed for RLVs that took place during the initial 10 seconds of red. Drivers started moving from their position during the final stage of red phase resulting in more number of violations during timer on scenario. On the other hand, timers assisted drivers make better decision regarding stopping or crossing the intersections at the end of green, thus reducing violations during the initial stage of red phase. Timer off scenario enlarged total ranges of both Type I and II dilemma zones at the onset of yellow and brought Type II dilemma zone earlier.

Identification of free flow condition on two-lane intercity highways under heterogeneous traffic condition

Abstract: Session 1.1 Session 1.2 Session 1.3 Session 1.4 Session 1.5 Session 1.6 Session 1.7 Session 1.8 Public Transport 1Chair: Alexa Delbsosc, Monash University Transport SurveysChair: Mark Davis, IPSOS Aviation/MaritimeChair: Nicholas Bardell, RMIT Travel Behaviour ChangeChair: Brett Smith, The University of Journey Management 1 / Traffic EngineeringChair: Flood RecoveryChair: Paul Flanagan, Department of Safe Systems 1Chair: Marcus James, Department of Economic MethodsChair: Mark Harvey, Bureau of Room: Grand 3 Room: Grand 4 Room: Lake 3&4 Room: Element Room: Grand 1 Room: Grand 2 Room: Lake 1&2 Room: Park Paper # 194 Real-time Information System for Spreading Rail Passengers across Train Carriages: Agentbased Simulation Study Sanghyung Ahn, Jiwon Kim, Antonius Bekti, Liang-Chuan Paper # 1 Smartphone-Based Travel Surveys: Where Are We Heading? Stephen Greaves, Richard Ellison and Nina Marie Belarmino Verzosa Paper # 60 Australian maritime transport policy: what drives or constrains success? Phil Potterton Paper # 55 'Gamification’ in transport interventions Barbara T.H. Yen, Corinne Mulley, Matthew Burke and Simon Washington Meeting community expectations a framework for extending the Level of Service concept beyond congestion Peter Cairney ARRB Group (AUS) Pavement Treatments and Lessons Learnt from the Flood Reconstruction Work in the Transport Network Reconstruction Program (TNRP) in Queensland Jeffrey Lee and Lory Noya Road diet safety an Australian viewpoint Tariro Makwasha ARRB Group (AUS) Sources and Uses of Vehicle Operating Costs and Associated Road User Cost Estimates in Australia Cliff Naude ARRB Group (AUS)