Shriniwas S. Arkatkar

Time occupancy as measure of PCU at four legged roundabouts

This study is carried out to estimate the passenger car unit (PCU) values of different vehicle categories at a typical four-legged roundabout based on the concept of time occupancy. A stream equivalency factor (k) has also been developed based on the estimated PCU to convert the heterogeneous traffic flow into a homogenous stream equivalent without making use of PCU factors. Relationship between entry flow and circulatory flow has been plotted based on the observed data corresponding to the time period in which there was queue formation in the approach. Further, estimated critical gap and follow-up time have been used to derive the capacity by HCM 2010 equation. A multiplicative adjustment factor is suggested for the use of HCM 2010 equation directly in the field to estimate entry flow under heterogeneous traffic condition. The study results may be suitable for revising the code of practice, named IRC 65–1976, and useful for ongoing national-level efforts of developing Indian Highway Capacity Manual.

Effect of traffic composition and emergency lane on capacity: a case study of intercity expressway in India

ABSTRACT The study is intended to investigate the effect of traffic composition and the use of a paved emergency lane on capacity. Ahmedabad–Vadodara four-lane divided intercity expressway (Mahatma Gandhi expressway, designated as NE-1) which has an emergency lane on either side is taken as a case study. For modeling traffic flow on expressway, a microscopic simulation technique is employed in this study. The simulation model was developed, calibrated, and validated for rendering as well as replicating the real traffic conditions. Results of the study show that the capacity is greatly influenced by emergency lanes and traffic composition. The result of the present study is expected to highlight the ongoing national-level efforts of developing guidelines for Indo-Highway Capacity Manual.

Methodology for simulating heterogeneous traffic on expressways in developing countries: a case study in India

The prevailing roadway and traffic conditions on expressways in India are vastly different when compared with the other roads in India and also, there is no perfect lane-discipline. The knowledge of roadway capacity is an important basic input required for planning, design, analysis, and operation of roadway systems. Hence, this work aims to model traffic flow on Indian urban expressways with specific reference to Delhi–Gurgaon expressway and estimate its capacity using the micro-simulation model using VISSIM 5·40. For this purpose, the field data collected on traffic-flow characteristics on expressways was used in calibration and validation of the simulation model. The validated simulation model was then used to develop fundamental traffic–flow relationships, namely, speed–flow, speed–area occupancy, and flow–area occupancy for the traffic-flow levels, starting from near-zero until the capacity of the facility. The capacity of an eight-lane divided urban expressway in level terrain with 14·0-m wide road space (one direction of traffic flow) was found to be in the range of 9700–10 000 vehicles/h. Moreover, through sensitivity analysis using simulation model, the following relationships, (i) percentage trucks in the traffic stream and capacity-level flow and (ii) percentage of trucks in the traffic stream and capacity-level traffic-stream speed, were developed. The results and the overall methodology followed in this study for modeling traffic flow on expressways in India to determine the capacity estimates under varying traffic compositions may be very useful for the practitioners and also for the continuing efforts to prepare an Indian Highway Capacity Manual.

Exploring Performance of Intercity Expressway Using ITS-Based Technology

Traffic data collection under mixed traffic conditions is one of the major problems faced by researchers as well as traffic regulatory authorities. For mixed traffic observed in developing countries, no suitable tool is available for this purpose. Keeping in view the necessities of acquiring an extensive database and the difficulties associated with its collection, ITS techniques can be implemented as an accurate and efficient methods of data collection. Among the emerging methods, Bluetooth-based sensors are gaining popularity, but the number of active Bluetooth devices in the traffic stream in India is generally very low and is hindrance to the effectiveness of data collection. Thus, the main aim of this research is to test the reliability of such Wi-Fi/Bluetooth-based sensor which is one of the most reliable and easy-to-use instruments that can aid us in solving above parameters efficiently. Exploration for the performance of such ITS-based technology is carried out in the determination of traffic flow parameters on NE-1 expressway of India and thereby validating the results with the help of videography survey data.

Multimodal of Lateral Transport System: A Case Study of Successful Cities Worldwide

These days, inefficient utilization of transportation network has turned out to be one of the significant issues for fast growing urban regions. Numerous initiatives are taken by the governments keeping in mind the end goal to evolve sustainable transportation by increasing the mode share of public transportation system; particularly the bus services. The major deficiency with the present public transport system is lack of proper first and last mile connectivity, delays of buses due to traffic density, improper route management of buses, etc. Past studies have demonstrated that coordinated planning and usage of multimodal transport system may prompt increment in mode share of public transport and may enhance effectiveness of transportation network. In this context, the present paper is an endeavor to examine the current multimodal transportation framework running effectively in the global cities, London, Hong Kong, and Singapore, with exemplary multimodal transport systems The five noteworthy mainstays of the multimodal transport that is physical joining, operational incorporation, informational integration, toll coordination, and institutional combination are reviewed briefly for each the selected urban areas. Focus of the present paper is simply to see how the idea of multimodal transportation framework can help the local authority to run the transportation system in a productive way.

Methodological Framework for Modeling Following Behavior of Vehicles Under Indian Traffic Scenario

The present research work is originated with an intent of studying traffic flow characteristics on intercity. For this purpose, two expressway sections: (i) Pune-Mumbai Expressway and (ii) Ahmedabad-Vadodara Expressway were selected, as these are the best available roads in category of intercity expressways, in India. During the course of work, it was found that data may not be fully adequate to develop Measure of Effectiveness (MOEs) thresholds. Consequently, simulation-based approach is to model the traffic flow on selected study sections. With this motivation, simulation model, namely, VISSIM-9.0 was calibrated using newly developed methodology for mixed traffic conditions. In particular, driving behavior parameters were calibrated using high-quality vehicular trajectories. A well-calibrated simulation model was then applied for developing speed-flow-density fundamental diagrams, and thereby determining capacity and Level-of-Service (LoS) thresholds using density and V/C ratio. It was found that the capacity value for six-lane divided expressway (three lanes in each direction) is determined as about 7500 PCU/h/direction, which reasonably matches with the US-HCM (2010) guidelines. It is anticipated that the proposed method of calibrating vehicle-following driving behavior using high-quality trajectory data is transferable to other mixed traffic conditions.

Influence of Driving Environment on Safety at Un-signalized T-intersection Under Mixed Traffic Conditions

Road traffic safety is an important issue and should be given utmost priority by traffic engineers. This research aims to proactively evaluate safety for two un-signalized T-intersections along the western frontier of India with varying driving environment under mixed traffic condition using surrogate safety measure, Post Encroachment Time (PET). PET for different vehicle category as per approach leg was extracted. The Generalized Extreme Value (GEV) was found to be the best fitted distribution for explaining the temporal variations observed in PET values and was further extended to estimate crash probability. It was observed that driving environment has a prominent effect on crash probability. Improved driving environment reduced crash probability at the intersection. Results indicated minor approach road users comparatively have more crash probability to major approach road users. Median to be introduced at undivided intersection to enhance the driving environment and speed breakers, sign board installation is suggested at both the intersections.

Application of Trajectory Data for Investigating Vehicle Behavior in Mixed Traffic Environment

The research work reported here investigates driving behavior under mixed traffic conditions on high-speed, multilane highways. With the involvement of multiple vehicle classes, high-resolution trajectory data is necessary for exploring vehicle-following, lateral movement, and seeping behavior under varying traffic flow states. An access-controlled, mid-block road section was selected for video data collection under varying traffic flow conditions. Using a semi-automated image processing tool, vehicular trajectory data was developed for three different traffic states. Micro-level behavior such as lateral placement of vehicles as a function of speed, instant responses, vehicle-following behavior, and hysteresis phenomenon were evaluated under different traffic flow states. It was found that lane-wise behavior degraded with increase in traffic volume and vehicles showed a propensity to move towards the median at low flow and towards the curb-side at moderate and heavy flows. Further, vehicle-following behavior was also investigated and it was found that with increase in flow level, vehicles are more inclined to mimic the leader vehicle’s behavior. In addition to following time, perceiving time of subject vehicle for different leading vehicles was also evaluated for different vehicle classes. From the analysis, it was inferred that smaller vehicles are switching their leader vehicles more often to escape from delay, resulting in less following and perceiving time and aggressive gap acceptance. The present research work reveals the need for high-quality, micro-level data for calibrating driving behavior models under mixed traffic conditions.

Performance Comparison of Bus Travel Time Prediction Models across Indian Cities

Road traffic congestion has become a global worry in recent years. In many countries congestion is a major factor, causing noticeable loss to both economy and time. The rapid increase in vehicle ownership accompanied by slow growth of infrastructure has resulted in space constraints in almost all major cities in India. To mitigate this issue, authorities have shifted to more sustainable management solutions like Intelligent Transport System (ITS). Advanced Public Transportation System (APTS) is an important area in ITS which could considerably offset the growing ownership of private vehicles as public transport holds a noticeable mode share in several major cities in India. Getting access to real-time information about public transport would certainly attract more users. In this regard, this work aims at developing a reliable structure for predicting arrival/travel time of various public transport systems under heterogeneous traffic conditions existing in India. The data used for the study is collected from three cities—Surat, Mysore, and Chennai. The data is analyzed across space and time to extract patterns which are further utilized in prediction models. The models examined in this paper are k-NN classifier, Kalman Filter and Auto-Regressive Integrated Moving Average (ARIMA) techniques. The performance of each model is evaluated and compared to understand which methods are suitable for different cities with varying characteristics.

Traffic operations and capacity analysis in India

In India rapid urbanization and improved socio-economic status from past few decades has resulted in high vehicular growth. India is urbanizing at rapid pace with urban population rising much faster than its total population. Level of urbanization has increased from 17.29% in 1951 to 31.6% in 2011. India is competing with the fastest growing countries in the world. As reported in (National TransitOriented Development) NTOD policy (MOUD (Ministry of Urban Development) [2016]), the urban population in India, which is nearly 377 million, is poised to grow to 600 million by 2030. The urban population of India contributes 65% of country’s Gross Domestic Product (GDP), which is expected to grow to 75% as the Indian cities are growing at a rate faster than other cities in the world. Obviously, with this widespread development, negative impacts are becoming more severe with mixed traffic behavior on urban streets as pedestrian, bicycles, buses, cars, motor cycles/scooters, auto rickshaw, cycle rickshaw share the same street space creating inefficient and unsafe mobility conditions. These impacts have offered lot many new opportunities to researchers, taking up good research studies, which are directed toward understanding transportation-related problems in a better way. The knowledge of traffic flow characteristics is a very important basic input required for planning, analysis, and operation of roadway systems. The road traffic in developing countries like India is highly heterogeneous comprising vehicles of wide ranging static and dynamic characteristics (Arasan and Arkatkar [2010]). The different types of vehicles of the heterogeneous traffic on Indian roads may be grouped into the following categories: (1) Buses, (2) Trucks, (3) Light commercial vehicles comprising large vans and small trucks, (4) Cars including jeeps and small vans, (5) Motorized three-wheelers, which include three-wheeled motorized vehicles to carry passengers and three-wheeled motorized vehicles to carry small quantities of goods, (6) Motorized two-wheelers, which include motorcycles, scooters, and mopeds, (7) Bicycles, (8) Tricycles, to carry passengers or small quantities of goods (Arasan and Arkatkar [2010]). The speeds of these vehicles vary from just five to more than 100 km/h. Due to the highly varying physical dimensions and speeds, it becomes difficult to make these vehicles to follow traffic lanes and the vehicles occupy any convenient lateral position on the road depending on the availability of road space at a given instant of time. Hence, expressing traffic volume as number of vehicles passing a given section of road or traffic lane per unit time will be inappropriate when several types of vehicles with widely varying static and dynamic characteristics are comprised in the traffic. In order to estimate the traffic volume or capacity of roadway sections under heterogeneous traffic conditions, it is necessary to study the interaction between the moving vehicles over a wide range of roadway and traffic conditions (Arasan and Arkatkar [2008]). The vehicles, of heterogeneous traffic with widely varying physical and operational characteristics such as the one prevailing on Indian roads, as mentioned earlier occupy, any convenient lateral position on the road based on the availability of space without any lane discipline. Hence, study of the interaction between moving vehicles under such heterogeneous traffic condition is highly complex. The problem of measuring volume at different levels including capacity of such heterogeneous traffic is addressed by converting the different types of vehicles into equivalent passenger cars and expressing the volume in terms of Passenger Car Unit (PCU) per hour (Arasan and Arkatkar [2010]; Dhamaniya and Chandra [2013]; Kumar et al. [2017]). The microscopic and macroscopic level analysis of traffic flow and vehicle operations for different type roadway and traffic conditions is a key aspect for studying any typical traffic operation. This also leads to understand the variation in capacity and LOS based on a particular type of roadway element/facility and its associated traffic conditions. The results obtained from detailed analysis on traffic operations for various roadway elements and facilities can be extremely helpful in demonstrating the innovative ideas on traffic flow modeling under Indian conditions. With the advent in technology and its deployment, there is substantial rise in the quality of research outputs, since last two decades. The enduring research works in India, from the specialization of “Traffic and Transportation Engineering,” mainly include (i) mixed traffic flow modeling on varying roadway classes and traffic conditions, (ii) traffic flow parameter predictions, (iii) traffic operation control and management, (iv) traffic safety and vulnerable road users, (v) ITS applications and traffic management. For instance, a maiden attempt (from India) toward development of “Indian-Highway Capacity Manual” is undertaken on priority by group of premier institutions in India, in the form of a mission mode project for different categories of roads like Expressways, National Highways, State Highways, Rural and Urban Roads, separately. The principal goal of this research is to contemplate the nationwide characteristics of road traffic and further develop a manual for determining the roadway capacity and LOS for varying types of inter-urban and urban roads. This also includes controlled as well as uncontrolled Intersections, coupled with pedestrian facilities. Since, last decade in India, there is considerable rise in the number of events, such as conferences and workshops, organized for making available a solid platform for dissimilating research findings among researchers in transportation community. With this motivation, a National conference-cum-workshop titled, “Recent Advances in Traffic Engineering-2015 (RATE 2015)” was held at Sardar Vallabhbhai National Institute of Technology Surat (SVNIT Surat) during 3–4 July, 2015, in association with CSIR-Central Road Research Institute (CSIR-CRRI). The Conference was intended to bring together professional engineers, academicians, researchers, and others having keen interest in the field of Traffic and Transportation and have fruitful deliberations. Hence, it is the most apposite juncture to have a focused theme of the special issue as “Traffic Operations and Capacity Analysis in India,” for which the quality papers are selected after a rigorous review procedure prescribed by the journal. After this standard review procedure, I accepted total nine papers for this special issue, out of which six papers are to be published in this special issue and rest three will be published in regular issues, with a mention of its reference with this special issue. The remainder of this foreword