Ashoke Kumar Sarkar

Prioritization of Pavement Stretches Using Fuzzy MCDM Approach – A Case Study

Effective pavement management requires the prioritization of the road stretches for logical disbursement of the funds available towards maintenance of the pavement. Several methods have been developed and implemented towards this goal. However, the uncertainty involved with some of the parameters has not been addressed adequately in most of the works. One such parameter has been identified as the severity of distress which is difficult to assess accurately. Hence a Fuzzy Multi Criteria Decision Making (FMCDM) approach has been proposed in this paper. For demonstration of the approach, pavement distresses with respect to their extent and severity have been collected over a number of stretches. In addition, an expert opinion survey has been carried out to quantify the influence of these parameters on the functional condition of the pavement. Priority Index (PI) has been worked out, based on which the ranking of the stretches has been arrived at.

Study on Heterogeneous Traffic Flow characteristics of a Two-Lane Road

Abstract The paper presents traffic studies conducted by using a video capturing technique on the uninterrupted heterogeneous mix of vehicles plying on an undivided two-lane road facility. On the basis of the collected data, traffic characteristics pertaining to arrival, headway and speed distributions have been plotted considering suitable mathematical distributions to fit field observed values. The curves representing fundamental traffic flow relationships among three basic variables, namely speed, density and flow have also been established. Thus, a systematic attempt to enable the understanding of heterogeneous traffic flow parameters has been made through this exploratory study.

Evaluation of speed–flow characteristics on two-lane highways with mixed traffic

AbstractThe HCM (Highway Capacity Manual 2010) classifies two-lane rural highway that passes through developed areas as ‘Class III’ and suggests using Percent Free-Flow Speed (PFFS) as performance measure to define Level Of Service (LOS). Apparently, this performance measure addresses the main limitation associated with using Average Travel Speed (ATS) as a measure of performance. However, larger speed differential under heterogeneous traffic causes error in estimating Free-Flow Speed (FFS) and thus affects PFFS. This implication was examined in the present study using field data collected on a national highway approaching a city. Speed–flow equations were developed and intercept values were compared to the FFS obtained according to HCM guidelines. Comparison confirms a very close agreement between average FFS value and those obtained for different types of vehicle separately except for car. This consequently causes an error in estimating PFFS since the traffic composition consists of significant proporti...

Development of a model for estimating International Roughness Index from pavement distresses

Roughness of a stretch of pavement represents the collective effect of various distresses at a point of time. Several researches and agencies have developed models to predict roughness based on distresses. However, most of them have not considered a few common distresses usually present on the primary and secondary road networks in the developing countries. In this study, an attempt has been made to develop relationship between roughness and noticeable distresses commonly observed on Indian roads such as cracking, potholes, patching, rutting and ravelling. All these distresses have been considered in terms of extent and severity. The model is based on pavement distress data collected over 39.5 km length of road of different functional classes such as National Highways, State Highways and Major District Roads in Rajasthan state of India.

Integrated Rural Accessibility Planning (IRAP)

This is a case study based on an application of the Integrated Rural Accessibility Planning (IRAP) methodology in a rural area in the Indian state of Rajasthan. The article adopts a participatory approach to quantify accessibility needs for water source, education and health care for all 13 villages in the study area. The villages were then prioritized according to their needs for better accessibility. Villages with the worst accessibility levels in all three sectors are identified. A number of alternative proposals, generated in consultation with the representatives of the villagers, are evaluated and then the most suitable solutions are identified.

Application of Principal Component Analysis for Outlier Detection in Heterogeneous Traffic Data

Level-of-service (LOS) measures of two-lane highways exhibit incompatibility if the prevailing traffic is heterogeneous in character. Thus, such traffic warrants development of LOS criteria on the basis of compatible measures which capture its characteristics. The present paper has suggested the use of percent speed-reduction and percent slower vehicles, as the measures of performance, while defining LOS criteria. Defining such criteria is basically a classification problem and clustering could be applied as an effective technique for its solution. However, heterogeneity in the traffic mix results in the presence of significant proportion of outliers in the data set, which can distort the results and render into misleading or useless outcomes. The study considers principal component analysis to be an efficient technique in detecting outliers from the data set and accordingly applies it on the proposed LOS measures. An iterative process, adopted for removing outliers, indicates that significant proportion of outliers comprises of non-motorized traffic data; this accordingly ensures reliability of the data set. The study concluded the unfeasibility of LOS assessment of the entire traffic, considering both motorized and non-motorized modes, with respect to a common scale.

Preferred time headway of drivers on two-lane highways with heterogeneous traffic

Abstract This paper presents an investigation on the adequacy of one of the major performance indicators for two-lane highways, the percent-time-spent-following (PTSF) under changing driver’s behavior in choosing headways. Field study was conducted on a two-lane highway in India that exhibits heterogeneity in its traffic composition and a wide range of flow levels was covered while collecting data. The appropriate headway distributions were selected based on goodness-of-fit test. Exponential or Erlang distributions exhibit their aptness in describing headways up to a volume to capacity ratio of 0.3 and gamma and exponential distributions were compatible for headway data corresponding to a volume to capacity ratio of 0.4 and above. Around 40% drivers were observed to adopt headways 2 s or less at heavy flow when a car-following situation prevails; these headways are considered unsafe in several instances. Further, speed–headway relationships were established to assess a headway threshold beyond which vehicles could be considered free. Empirical investigation indicates a value of about 6 s under such traffic unlike 3 s as considered in PTSF estimation. Another major implication on PTSF is a few drivers move in a platoon by choice even if they have a gap of more than 6 s and passing opportunities.

COMMUTER PERCEPTIONS ON PRIVATE AND PUBLIC TRANSPORT MODES: A CASE STUDY.

In recent years, the emphasis on economic efficiency and the optimum utilization of existing transport infrastructures have featured high on the Governments agenda universally. South Africa is no exception and is currently seeking strategies to optimise capacity utilization and to achieve a level of integration between modes. Because of the previous apartheid regime, the transport facilities were provided without considering the population as a whole, but only for a minor section. Sometimes, expensive infrastructures were constructed in certain areas without proper planning. Chatsworth, one of the major suburban areas of the city of Durban, is a typical example of such kind of planning. To understand the reasons for the steady decline in rail patronage, a home interview survey was conducted amongst the commuters in this area in order to establish their attitudes, preferences and priorities concerning the existing transportation situation.

Study on Plastic Coated Overburnt Brick Aggregate as an Alternative Material for Bituminous Road Construction

There are different places in India where natural stone aggregates are not available for constructional work. Plastic coated OBBA can solve the problem of shortage of stone aggregate to some extent. The engineers are always encouraged to use locally available materials. The present investigation is carried out to evaluate the plastic coated OBBA as an alternative material for bituminous road construction. Shredded waste plastics are mixed with OBBA in different percentages as 0.38, 0.42, 0.46, 0.50, 0.54, and 0.60 of the weight of brick aggregates. Marshall Method of mix design is carried out to find the optimum bitumen content of such bituminous concrete mix prepared by plastic coated OBBA. Bulk density, Marshall Stability, flow, Marshall Quotient, ITS, TSR, stripping, fatigue life, and deformations have been determined accordingly. Marshall Stability value of 0.54 percent of plastic mix is comparatively higher than the other mixes except 0.60 percent of plastic mix. Test results are within the prescribed limit for 0.54 percent of plastic mix. There is a significant reduction in rutting characteristics of the same plastic mix. The fatigue life of the mix is also significantly higher. Thus plastic coated OBBA is found suitable in construction of bituminous concrete road.

Novel Area Occupancy–Based Method for Passenger Car Unit Estimation on Multilane Urban Roads Under Heterogeneous Traffic Scenario

This research was aimed at developing an area occupancy–based method for estimating passenger car unit (PCU) values for vehicle categories under heterogeneous traffic conditions on multilane urban roads for a wide range of traffic flow levels. First, PCU values of vehicle categories were determined according to the Transport and Road Research Laboratory definition and replaced the commonly considered measure of performance speed with area occupancy using simulation. The PCU values obtained were found to be significantly different for different volume-to-capacity ratios; this result shows that the PCU value is dynamic in nature. While the dynamic nature of PCU values is well appreciated, practitioners may prefer a single set of optimized PCU values (unique for each vehicle category). Hence, a new method with a matrix solution was proposed to estimate the optimized or unique set of PCU values with area occupancy as the performance measure. To check the credibility of the proposed method, the estimated PCU values were compared from existing guidelines regulated by the Indian Roads Congress (IRC) and values estimated with the widely accepted dynamic PCU concept of speed–area ratio. Results show that the PCU values suggested by IRC and the dynamic PCU concept using the speed–area ratio underestimate and overestimate the flows, respectively, at different traffic volumes. However, the values obtained with the area-occupancy concept were found to be consistent with the traffic flow in a cars-only traffic situation at different flow conditions. The derived set of optimized PCU values proposed can be useful for traffic engineers, researchers, and practitioners for capacity and level-of-service analysis under heterogeneous traffic conditions.