JournalTOCs

Transportation in Developing Economies
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Hybrid journal (It can contain Open Access articles)
ISSN (Print) 2199-9287 - ISSN (Online) 2199-9295
Published by Springer-Verlag

[2626 journals]

Real-Time Traffic Congestion Information from Tweets Using Supervised and
Unsupervised Machine Learning Techniques
- Abstract: For many decades automated sensors, such as acoustic, optical, pneumatic, magnetic, inductive sensors and video-based image processing solutions were used for collecting data on traffic flow, speed, density, travel time etc. Using these data, the level of congestion is indirectly estimated. However, most of these sensors are costly and location-based. In addition, they cannot find the reason for congestion. To address these limitations, use of social media as a source of traffic information has been explored recently. Some of them, such as Twitter, are open source and popular throughout the world. Earlier studies that reported the use of Twitter feeds for traffic information are limited and used machine-learning techniques based on supervised learning, which needs labelled data that are difficult to obtain. Hence, this paper compares the unsupervised and supervised approaches to extract traffic-related tweets and develops a method to give the probability of level of congestion in real-time. The methods developed were applied to the tweets from Chennai city to extract the congestion information in real time, the results were validated through newspaper reports of heavy traffic congestion events. The obtained results showed a good correlation with the real congestion events.
  PubDate: 2019-10-04
Development of Composite Level of Service for Signalized Intersections
Under Heterogeneous Traffic Conditions
- Abstract: Level of Service (LoS) is the easiest and widely used method for the assessment of quality of service provided to the road users. Depending upon the measure of LoS, appropriate actions may be initiated by the decision makers to enhance the better function of the system if necessary. But intersections are the critical location, where improvement measures for motorized vehicle users might affect the non-motorized vehicle users undesirably. This study focuses on controlled intersections and the efficiency measures of the signalized intersection. Many guidelines have provided the values of LoS of motorized and non-motorized traffic separately, even though they share the same space and time at the intersection. But to understand the efficiency of the whole intersection, all the users should be quantitatively measured with respect to a single unit. This research identifies performance parameters namely, vehicular volume, vehicular delay, pedestrian volume and pedestrian delay which directly influence the cycle time and the operating characteristics of signalized intersection. Empirical traffic models were developed between these performance measures and the best fit relationships were established. A Composite Level of Service (CLoS) which quantitatively measures all the users of an intersection irrespective of mode of transport is estimated using stopped delay of the motorized vehicles and pedestrians of the intersection. This CLoS helps to identify the efficiency of the whole signalized intersection in a single unit. The empirical models and CLoS was validated and application of this study was explained further using ground data.
  PubDate: 2019-09-12
Calibration of Vehicle-Following Model Parameters Using Mixed Traffic
Trajectory Data
- Abstract: A number of models for car following have been proposed for homogeneous traffic and some of these have been modified or adapted to represent mixed traffic conditions in India. Vehicle-following behavior under mixed traffic is both complex and challenging and cannot be adequately captured by conventional lane-based following models and their variants. For example, the behavior of a subject vehicle in a mixed traffic condition depends on the behavior of lead vehicle as well as the influence of neighboring vehicles. Most existing models are based on the longitudinal spacing and the relative speed of the lead and the subject vehicles. However, the vehicular interactions also depend on the lateral movements such as lateral spacing and lateral speed. Furthermore, the response of the subject vehicle also depends on the type of vehicles involved and their maneuvers in the surrounding space. This study aims to address some of these gaps in the existing vehicle-following models for mixed traffic. Mixed traffic trajectory data collected from the mid-block section of a six-lane divided urban arterial road in Chennai city were used for this study. From the data set, leader–follower vehicle pairs identified based on three different methods: influence area method, headway method, and video data tracking are compared, and the most suitable method is chosen for further analysis. Variation of driver behavior due to different factors such as follower’s speed, relative spacing, lateral position, vehicle types, and following behaviors were examined. Calibration and validation of the models were done for different leader–follower vehicle pairs. The results show that the model parameters vary with not only by subject vehicle type, but also by leader–follower pairs. In addition, there is a significant effect of factors such as lateral position of vehicles and types of following behaviors. This study will find application in developing more realistic mixed traffic simulation models by including these factors.
  PubDate: 2019-09-06
Multivariate Analysis on Dynamic Car-Following Data of Non-lane-Based
Traffic Environments
- Abstract: The difficulties of the microscopic models in accurate representation of the real traffic phenomena stem from its complexities in the collection and processing of reliable time-series car-following data of non-lane-based traffic environments. Proper estimation of car-following data can suitably ameliorate the realism of traffic sub-models and is still a demanding task. This study describes an image-based in-vehicle trajectory data collection system for the estimation of reliable dynamic time-series data, using camera calibration and in-vehicle GPS information. A copula-based methodological framework is also investigated in this study for evaluating safety in the car-following processes, by accommodating the dependence structure of longitudinal gap, centerline separation and vehicle speeds. Results of the study demonstrated the importance of centerline separation in apprehending the car-following processes. In particular, the probability of maintaining lower gaps increases with the decrease in speed and increase in centerline separation. A 15–20% reduction in the longitudinal gaps is observed for speeds greater than 60 kmph. As importantly, the study recommends the applicability of tri-variate Gaussian copula in assessing the safety or ‘safe distance-keeping’ criteria of drivers in the car-following processes, which can indeed augment the accurate representation of drivers’ behavior and development of the car-following models, advanced driver assistance systems and for safety evaluation in the car-following process of non-lane-based traffic environments.
  PubDate: 2019-08-29
Effect of Joint- and Pavement-Related Parameters on Load Transfer
Characteristics of Aggregate Interlocked Jointed Concrete Pavement
- Abstract: In concrete pavement, load transfer through the natural mechanism of interlocking action of the aggregate particles has been found to be effective for moderate to low traffic volume roads. This paper investigates the influences of some of the joint-related parameters (e.g., roughness, crack width and aggregate size) and pavement-related parameters (e.g., slab depth and modulus of subgrade reaction) on the load transfer efficiency (LTE) of an aggregate interlocked joint in concrete pavement. A three-dimensional finite element analysis of a jointed concrete pavement has been carried out. An aggregate interlocked joint with irregular fractured surfaces has been modeled in this work. The nature of the fractured surfaces or its roughness influences the LTE of the joint. The effects of varied roughness, crack widths and maximum aggregate size on the LTE of a joint have been investigated in the present work. It has been found that LTE increases with increase in roughness levels for all aggregate sizes and crack widths. The effects of depth of concrete slab and modulus of subgrade reaction on LTE have also been investigated. LTE has been found to increase with increase in slab depth; whereas it decreases with increase in the modulus of subgrade reaction.
  PubDate: 2019-08-06
Effect of Horizontal Curve Geometry on the Maximum Speed Reduction: A
Driving Simulator-Based Study
- Abstract: Operating speed reduction models can be used to evaluate the geometric design consistency. The proposed study developed a maximum speed reduction model for drivers habituated in weak lane disciplined driving conditions. The required experiment was carried out on a fixed-base driving simulator. The speed profiles of 48 participating drivers along 24 different tangent-curve configurations were recorded. The maximum speed at the preceding tangent and the minimum speed in the following curve were used to estimate the maximum speed reduction (MSR) of each subject driver. A multiple regression model was developed for the obtained 85th percentile maximum speed reduction data and the road geometric parameters such as radius, curvature, preceding tangent length, curve length, gradient, shoulder width, and extra-widening. The developed model identified curvature (i.e., the inverse of radius) and preceding tangent length as predictor variables. Based on the obtained results, a nomogram for road geometric safety evaluation is proposed in the paper.
  PubDate: 2019-08-06
Numerical Study with Field Data for Macroscopic Continuum Modelling of
Indian Traffic
- Abstract: Heterogeneous traffic as observed in several south Asian countries is characterized by complex interactions of widely varying vehicle types that do not follow lanes and with smaller vehicles filling any gaps available. This paper discusses on four main components of macroscopic simulation of traffic flow in the Indian traffic context. One of the prime component, namely the traffic flow model, is discussed in detail with respect to the continuum modelling approach.
  PubDate: 2019-08-06
Travel Time Reliability Analysis on Selected Bus Route of Mysore Using GPS
Data
- Abstract: This research study aims at evaluating the travel time reliability indices like Buffer Time Index, Planning Time Index and Travel Time Index over space and time on selected city bus route of Mysore city, India. Also, this study focuses on developing the correlation models between the bus journey speed and flow for different type of urban roadway conditions. These models are observed to be performing better and hence can be used for predicting traffic volumes for similar roadway conditions when traffic data are not available from field. Further, the variation of volume-to-capacity (V/C) with travel time reliability indices is also studied in detail. The k-means clustering analysis is performed for classifying the reliability measures with respect to V/C and Coefficient of Variation. It is expected that the developed reliability measures may be useful for defining level of service for bus routes in class-II cities (cities with lesser population than metropolitan cities).
  PubDate: 2019-08-01
Development of a Video Image Processing-Based Micro-level Data Extractor
for Non-lane-Based Heterogeneous Traffic Conditions
- Abstract: Limited studies are conducted to develop trajectory-level data extraction tools for non-lane-based heterogeneous traffic conditions prevalent in developing countries, like India. Comprehending this research gap, the development of an automation-based conceptual methodology is crucial, that would help researchers to understand and assess heterogeneous, non-lane-based traffic at micro-level. Microscopic parameters like individual vehicular trajectory and inter-vehicular spacing, in lateral as well as longitudinal dimensions, play significant roles in understanding traffic dynamics. A major hindrance in acquiring the huge data required for this purpose is the high demand of manpower and time in extracting traffic data manually with desirable accuracy. Implementing automated systems can mitigate the burden of data acquisition. One of the promising ideas for effective traffic analysis is video-based image processing, using which highly accurate data can be obtained by suitably calibrating the threshold values, thereby optimizing it for a given video. In this study, an attempt has been made to develop an automated image processing tool using MATLAB, to first classify vehicles under varying roadway and traffic conditions, and then to obtain lateral as well as longitudinal spacing maintained, based on the detected positions of vehicles on the road over time. The developed traffic data extractor also provides output on individual vehicle trajectory, and, hence, travel times and speed profiles of different vehicle categories. Evaluation results showed an MAPE of less than 13%, suggesting its reliability under varying mixed traffic conditions. The logic developed in this research is expected to cater well for similar traffic conditions in other Asian countries.
  PubDate: 2019-07-31
Using Link-Level Archived Automatic Vehicle Location Data to Assess
Transit System LOS at Bus-Stop Level
- Abstract: The focus of this paper is on assessment of transit system level-of-service (LOS) at bus-stop level using the proposed percentage-based performance measure and compare it with the fixed-range-based performance measure. Data captured through automatic vehicle location (AVL) units installed on Charlotte Area Transit System (CATS) buses for 2012 and archived was used to develop query tools and compute link-level transit system performance measures, conduct analysis, and derive meaningful interpretations. The query tools developed computed performance measures by comparing actual bus travel time along selected links (between two consecutive fixed bus stops) with the scheduled travel time along the same link for each run in a year. Actual delay time and early arrivals as well as percentage of delays and early arrivals were computed to assist in the assessment. The analysis was conducted by time-of-the-day and day-of-the-week, for both travel directions, along selected bus routes/segments to assist in assessing the applicability of the measures. Findings from the research indicate that percentage-based performance measure is more reliable than fixed-range-based performance measure (delay or difference in travel time) for planning and assessment of operational performance by transit agencies.
  PubDate: 2019-06-24
Car Trip Generation Models in the Developing World: Data Issues and
Spatial Transferability
- Abstract: In many countries of the developing world, it is difficult to conduct large-scale household travel surveys to collect data for travel behaviour model estimation and application. This paper focuses on two candidate solutions to the problem: (1) developing models that can be applied for prediction using secondary data collected for other purposes and include socio-demographic information but do not include transport specific information such as the car and/or transit pass ownership (e.g. census, public health records, etc.), (2) ‘borrowing’ a model developed using data from a similar city within the same region. In the first approach, we investigate the feasibility of developing car trip generation models which imputes the car ownership variable with estimated car ownership propensities. The proposed framework is applied in two East African cities, Nairobi and Dar-es-Salaam. The estimation results indicate that for both cities the proposed approach outperforms the models that exclude the car ownership variable. In the second approach, we investigate the spatial transferability of the models developed in the first approach between the two cities to evaluate if it is justified to apply models from one developing country to another in the absence of local models. Results indicate that though some of the estimated parameters are not significantly different from each other between the two cities, statistical tests do not support direct transferability of all the models from Nairobi to Dar-es-Salaam or vice versa. However, interestingly, the simpler model (which excludes car-ownership) outperforms the model with imputed car ownership propensity in terms of transferability. These findings provide useful insights into the development of trip generation models under data constraints which can practically be very useful for developing countries.
  PubDate: 2019-04-20
Pedestrian Facilities and Perceived Pedestrian Level of Service (PLOS): A
Case Study of Chittagong Metropolitan Area, Bangladesh
- Abstract: The promotion of active transport (a type of sustainable transportation) such as walking is a form of response against environmental pollution engendering from transport sector. Pedestrian level of service (PLOS) is a measurement tool to evaluate the degree of pedestrian accommodation on roadway to provide a comfortable and safe walking environment. The roadway characteristics-based model to measure PLOS has been widely applied since this approach is conceived as being transferable to different contexts. We present a comprehensive framework to measure the influence of pedestrian facilities on perceived PLOS qualitatively and quantitatively. We modeled triangular relationships among pedestrian facilities, perceived roadway conditions (accessibility, safety, comfort, and attractiveness), and perceived PLOS to identify pedestrian facilities, related to footpath, carriageway, and transit, influencing perceived PLOS. We developed these models for a case study of Chittagong Metropolitan Area in Bangladesh. Poor condition of pedestrian facilities in the region resulted in PLOS B as the highest tier of perceived PLOS. Findings of this study showed that accessibility and attractiveness influenced the perceived PLOS for footpath, carriageway, and transit, whereas safety is an important roadway condition for carriageway and transit facilities. We further measured the influence of 22 selected parameters of pedestrian facilities on roadway conditions and perceived PLOS. We concluded that achieving a better perceived PLOS is dependent on the availability, maintenance, and planning of different pedestrian facilities, as improper placement and poor condition of such facilities increased the probability that a lower level PLOS will be perceived.
  PubDate: 2019-04-09
Equivalency Factor Based on Acceleration Noise for Mixed Traffic Condition
- Abstract: Vehicular traffic on urban roads in developing countries like India is heterogeneous in nature with wide variety of vehicles, both motorized and non-motorized, sharing the same road space. This creates difficulty in accounting the traffic characteristics of the stream. Determination of traffic characteristics is required for flow modeling and capacity analysis which helps in planning and designing new roads and maintenance and management of existing ones. A solution for homogenization of this non-lane-based mixed traffic condition is the usage of passenger car units (PCU). Studies were carried out by various researchers in this direction to develop realistic PCU values for various categories of vehicles taking into consideration parameters like speed, headway, density, projected and influence area, etc. Urban roads are characterized by frequent changes in acceleration–deceleration characteristics of vehicles mainly due to the interaction of vehicles in the stream. This variation in acceleration–deceleration characteristics can be captured in terms of acceleration noise which is defined as the standard deviation of acceleration–deceleration values. Acceleration noise is a better parameter in estimating PCU compared to other parameters which are more suited for homogenous traffic conditions. Acceleration noise is found to follow a normal distribution under smooth homogenous traffic condition; while under mixed non-lane-based conditions, it deviates from the normality. This variation can be measured using skewness and this can be considered as a measure for homogenizing the vehicles on urban roads. In this study, attempt was made to quantify PCU of a vehicle in terms of this variation in acceleration–deceleration. Speed and acceleration were measured using hand-held GPS devices which were mounted on the vehicles. Acceleration noise and its skewness were determined. PCU of a vehicle category was expressed as a ratio of skewness of acceleration noise of the vehicle under consideration to that of passenger car. Since field data were insufficient to account for wide range of volume conditions, micro-simulation technique was employed. A typical four-lane divided urban road stretch was simulated and the traffic characteristics of all the four categories of vehicle were extracted. Traffic volume and composition were varied till the volume reached the capacity. PCU was estimated as per the above concept under varying traffic flow conditions. These values were compared with the values suggested by previous studies and it was found that this method of estimating PCU is able to capture the variation in vehicular composition and vehicular interactions efficiently. Thus, it can be concluded that acceleration noise is a better parameter for representing the PCU values on urban roads.
  PubDate: 2019-04-05
Impact of Road Infrastructure Land Use and Traffic Operational
Characteristics on Pedestrian Fatality Risk: A Case Study of Kolkata,
India
- Abstract: Pedestrian safety in urban India is an issue of growing concern. While an extensive body of literature is available on the identification of elements related to the pedestrian’s risk, the studies are mainly conducted in urban areas of developed countries, where the condition of infrastructure, built environment, road user’s behavior and perception are very different from Indian cities. As a result, findings from these studies may only be partially applicable to the cities of developing countries such as India. The present study makes an attempt to fill the gap by analyzing historical crash records obtained from Kolkata police and identifies the hazardous corridors and network locations posing the highest risk to the pedestrian. Subsequently, the binary logistic regression models are developed to identify the risk factors associated with road infrastructure, land use, and traffic operational characteristics. Based on the statistical assessment carried out in this study, there is evidence that factors such as road width, land use type, the absence of designated bus stop facility, inadequate sight distance, average daily traffic and pedestrian volume, and pedestrian–vehicular interaction considerably affect pedestrian safety at the intersections. On the other hand, road width, land use type, inadequate sight distance, the absence of designated bus stop facilities significantly influence pedestrian safety at midblock road segments. The knowledge of the risk factors specific to a location on the road network is helpful for incorporation and/or modification of the particular planning and design elements to reduce risk.
  PubDate: 2019-04-05
Passenger Car Equivalency Factors Under Platooning Conditions
- Abstract: Heterogeneous traffic existing in developing countries such as in India is characterized by vehicles with very diverse static and dynamic characteristics. The various types of vehicles, other than cars in the heterogeneous traffic stream can be converted into equivalent passenger cars so as to express the heterogeneous traffic volume in terms of corresponding passenger car units (PCU). The subject of PCU has been studied on intercity, urban roads and at intersections controlled by traffic signals quite extensively. But studies on PCU values of vehicles on the downstream of signalized intersections have not been explored so far. The arterial links existing at downstream of traffic signals are designed to progress traffic with varying acceleration and deceleration. Vehicular interactions which take place within platoons and between platoons along such arterials are the predominant factors affecting vehicular progression. Hence there is a need to derive PCU values of vehicles along signalized corridors. The present study analyzes traffic flow data collected at the downstream of a signalized urban arterial to determine PCU values for various types of vehicles based on three methods. One method is the homogenisation coefficient method whereas the other one is the speed-area ratio method. The third one is a new method based on speed differential and area ratio is proposed in this paper which considers the effect of speed variation of vehicles for estimating PCU values. In this study, PCU values estimated based on speed differential-area ratio concept are found to be more logical compared to other methods as this method could incorporate the considerable variation in static and dynamic characteristics of various vehicles which progress along the downstream of intersections.
  PubDate: 2019-04-05
Public Opinion Analysis of the Transportation Policy Using Social Media
Data: A Case Study on the Delhi Odd–Even Policy
- Abstract: Twitter, a microblogging service, has become a popular platform for people to express their views and opinions on different issues. A sentiment analysis of the tweets can help in understanding the public opinion on different government decisions. This paper used Twitter data to extract the sentiments of people during the Phase 1 and Phase 2 of the odd–even policy implemented by the Delhi government to curb the air pollution and improve traffic flow. In this study, we used four different lexicon-based approaches: Bing, Afinn, National Research Council emotion lexicon, and Deep Recursive Neural Network-based Natural Language Processing software (CoreNLP) to extract sentiments from tweets and thereby assess overall public opinions. The daily trend obtained for each phase was normalized with the number of tweets and then compared using the Granger causality test. The causality test results showed that the trends obtained during the two phases were significantly different from each other. In particular, public sentiments were found to mostly turn negative during the later stage of the Phase 2 which indicates fading away of the public enthusiasm and positiveness towards the policy during the later stages of the policy implementation.
  PubDate: 2019-03-29
Influence of Strain Amplitude and Rest Period on Fatigue Life of
CRMB Modified Bituminous Mixture
- Abstract: This study focuses on the laboratory investigations carried out to quantify the fatigue life of viscosity grade 40 (VG40) and crumb rubber modified bituminous (CRMB) mixtures and the influence of rest period. Four-point beam bending experiments were carried out with strain-controlled loading at 20 \(^{\circ }\) C and 10 Hz frequency with and without rest period between two consecutive load cycles. The fatigue life was quantified using flexural stiffness. It was seen that the CRMB mixture exhibited low rate of reduction in flexural stiffness and better recovery during the rest period when compared to bituminous mixtures produced using VG40 binder.
  PubDate: 2019-02-21
Adaptation Policy Framework for Climate Change Impacts on Transportation
Sector in Developing Countries
- Abstract: The global response to climate change threat has been through mitigation by reducing the GHG emissions; however, some of the climate change effects are inevitable and unavoidable. Adaptation is seen as a necessary means of addressing these inevitable climate change effects, some of which are projected to bring more frequent and severe precipitation resulting in floods. This threat of floods reinforced by rapid urbanization, resulting in urban flooding has become a looming threat to road transportation which disproportionally affects developing countries. There is an urgent need to adapt transport infrastructure to the anticipated climate change effects to minimize human as well as economic losses. In this paper, a consolidated review of literature on road transport-related climate change adaptation measures adopted across different countries around the world has been done, followed by the identification of barriers and adaptation challenges in developing countries such as India. Further, a novel methodological approach has been proposed for shaping adaptation policies in developing countries. It is aimed to enhance the resilience of transportation system specifically against urban flooding induced by climate change, reduce its impacts and strengthen the adaptive capacity of the system.
  PubDate: 2019-02-14
Controllability and Observability Analysis for Intelligent Transportation
Systems
- Abstract: In this paper, we present a novel methodology for analyzing the controllability problem on a freeway traffic network. The new framework investigates controllability in terms of flow information on arcs and the routing information. Macroscopic ODE-based traffic model is used to develop \((\rho )\) dynamics on a network arc which is then combined with another ODE model of the routing \((\pi )\) dynamics. Thus, obtained network dynamics is then linearized about the steady-state flows to establish a linear time invariant (LTI) dynamics. Controllability test for LTI systems is then used to test controllability of the system. Methodology is first tested on a few sample networks and then more general results are obtained. An alternate analysis for controllability problem is also presented by treating the problem as a dual of observability problem.
  PubDate: 2018-12-17
A Review of Service Assessment Attributes and Improvement Strategies for
Public Transport
- Abstract: Traffic externalities are growing continuously in cities due to increasing dependence of people on private motor vehicles (PMVs) for regular commute. While PMVs have some advantages such as privacy, flexibility, faster commute, comfort, and convenience, their use alone at the current growth rate is not sustainable. A well-planned and efficient public transport (PT) system will have the potential to efficiently and sustainably overcome these issues. This may not currently be the case in many cities, but can be, after appropriate user-centric improvements. This paper aims to review the existing literature to get a better understanding of: (1) service assessment attributes that can inhibit the use of PT, and (2) the possible improvement strategies that can effectively address the concerns related to each attribute. We developed cause and effect (Ishikawa) diagrams to connect service assessment attributes to corresponding interventions and improvement strategies.
  PubDate: 2018-11-03