Proceedings of the Sixth International Conference of Transportation Research Group of India

Resilient modulus of the layers is a key engineering property which is used in the design of the new pavement, as well as, while evaluating the existing pavement for possible rehabili-tation. These are based on IRC 37:2018 and IRC 115:2015 in India. As per IRC guidelines, the resilient modulus of the subgrade is evaluated using an empirical correlation with its CBR value, and for the base course, it uses an empirical re-lationship with the thickness of the granular layer and the resilient modulus of the subgrade. According to global prac-tice, this is a Level-2 design approach. Level-1 approach considers the resilient modulus based on the laboratory test for analysis. At present, the quality control during the con-struction stage is based on the examination of the density of a layer. In the absence of any standard relationship between density and resilient modulus, this approach does not guar-antee that the layer modulus is achieved. If this is done at this stage, then it will allow the engineer to take corrective measures at that time itself thus ensuring the functionality during design life. This paper attempts to use FWD-based analysis for subgrade and granular layer for proposing its possible use for construction stage quality assurance. The re-sults look promising and indicate that use of FWD is possi-ble with certain modifications in the loading mechanism.

Asphalt emulsion is extensively used in pavement preservation techniques. The curing process through which the emulsion gains intended binder properties is highly influenced by the emulsion type, curing time, and temperature, and relative humidity. In the domain of cement concrete characterization, the maturity method has been used to predict strength gain under the combined effect of time and temperature. The present paper attempts to apply the maturity method to evaluate the influence of time and temperature on the curing process of asphalt emulsion. In this study, asphalt emulsion (slow-setting asphalt emulsion) was cured at different curing temperatures (120,135,150, and 165 °C) and curing times (1, 2, and 3 hours). The asphalt emulsion residue obtained after different curing conditions was tested for rheological characterization. The results indicate that the curing conditions influenced the development of the properties of the emulsion residue. The maturity as a function of equivalent age and temperature showed a reasonable trend at higher curing temperatures.

In the present study, multiple stress creep recovery (MSCR) test and binder yield energy test (BYET) have been used to quantify the intensity of aging of an SBS polymer modified binder (PMB). Three different long-term aging levels, i.e., 20 h pressure aging vessel cycles (1CPAV), 40 h (2CPAV), 60 h (3CPAV), were selected to simulate the range of field aging behavior of modified binder. The MSCR results showed that with an increase in the cycles of aging, the percentage recovery of PMB increases. However, this enhanced recovery behavior of the binder is attributed to the increase in viscosity of base binder due to oxidative hardening and the degraded polymer network with aging has a minimal role to play. Thus, it can be concluded recovery parameter obtained from the standard MSCR test condition may not be suitable to judge the aging intensity of SBS PMB subjected to different aging cycles. On the contrary, BYET results showed a reduction in elastic recovery with an increase in aging cycles. Therefore, BYET-ER is a better parameter to quantify aging, particularly for SBS PMB.

The findings of a laboratory investigation into the ageing of asphalt mix are presented in this paper. VG30 and NRMB40, two binders, are investigated. Anti-oxidants were added to cashew nut shell liquid (CNSL) at a rate of 1–3% by weight of binder, with a 1% increase, in this research. Physical parameters of the binder, such as softening point, viscosity, ductility, and penetration, were used to assess the impact of employing CNSL in the binder. Fourier transform infrared spectroscopy is used to look at the characteristics of CNSL (FTIR). Multiple stress creep recovery test (MSCR) results using a dynamic shear rheometer show that adding CNSL to the VG30 increased the value of recovery at 1% CNSL, indicating better fatigue resistance; however, there are no significant effects on NRMB40 fatigue resistance, which continues to decrease as CNSL content increases. The fatigue test results acquired from repeated load tests for unaged and aged mixes are analysed using resilient modulus, which verifies the fatigue resistance values provided by MSCR.

Typically, the strength gain mechanism in RCCP, especially at initial days (aggregate interlocking), is different from its counterparts and thus requires accurate proportioning of aggregates with good workability properties. In this study, the various fundamental parameters of RCCP mix design, viz. aggregate gradation, vebe consistency, water-cement ratio (W/C), and aggregate-cement ratio (A/C), are studied critically through the particle packing approach. The IRC: SP-68 blending approach is compared with the modified Andreasson model. The parameters considered for gradation optimization are packing density, consistency, maximum dry density (MDD), and compressive strength. The results indicated the effectiveness of IRC gradation in terms of higher packing density (1–4%), MDD (0.1–2.7%), and compressive strength (12–67%) over the modified Andreasson model. The finding from this analysis suggests that designing RCCP mixes with the A/C between 5.7 and 6 and W/C in the range of 0.36–0.40 could achieve better consistency and strength properties.

To reduce moisture damage, anti-stripping agents are commonly used for the surface course of bituminous pavements. While a wide variety of anti-stripping agents are currently available, hydrated lime (HL) is widely used. The present study focused on studying the aging characteristics of bitumen and hydrated lime-treated mastic by using FTIR spectroscopy. HL was added to bitumen in contents of 20, 30, and 40% weight. The HL-treated mastics were oxidized at a constant temperature of 100 ℃ by varying the aging time. HL-treated mastics were evaluated for their aging compounds using FTIR spectroscopy. Results of obtained unaged and aged spectra were analyzed by calculating carbonyl and sulfoxide indices. Analysis of the spectra of aged mastic exhibited that the carbonyl indices increase with aging although at different rates depending on the aging duration and the dosage of lime. The sulfoxide compounds however exhibited very less sensitivity to duration of aging and dosage.

Ultra-thin Whitetopping (WT) is a technology in which a thickness of less than 100 mm of high early strength concrete pavement overlay is laid on a distressed bituminous pavement as a rehabilitation measure. WT modified by the application of Fiber-Reinforced Concrete (FRC) is adopted in this study. The three-dimensional finite element modeling developed in this study is for four-layered pavement with top fiber-reinforced WT layer, second bituminous layer, third sub-base, and bottom subgrade layer. Thickness and material properties of fiber-reinforced WT layer and bituminous layer are also varied for the parametric study. Loading is applied as per IRC:58-2015 and IRC:6-2010. Three different loading conditions such as interior, corner, and edge are considered, and maximum deflections at those loading positions are found out. The effect of temperature differentials is also studied. It is found that the deflection of fiber-reinforced WT pavement is maximum at slab corner, and it should be 5–10% times higher than edge and interior loading.

The multiple stress creep and recovery have been used to quantify the rutting behavior of the binder. The parameter such as non-recoverable creep compliance, percentage recovery, and retardation time depends on the temperature. The sensitivity of these parameters with the variation in the temperature is studied. This experimental investigation is carried out using one unmodified and one modified binder, and the test was carried out at unaged and short-term aged condition. The temperature regime of interest for this study is 40–70 °C. Multiple stress creep and recovery (MSCR) and steady shear tests were performed. MSCR tests were conducted using parallel plate geometry at 40, 50, 60, and 70 °C. The tests were conducted for two stress levels of 0.1 and 3.2 kPa. The steady shear viscosity at two different shear rates was also measured at these temperatures. The creep and recovery response of the bitumen at two different stress levels was found to be scalable, and Burgers’ model was used to predict the creep and recovery response of the bitumen. The Arrhenius constant for different binders and different aging conditions was determined using the viscosity data obtained from the steady shear test. The material functions such as creep compliance, percentage recovery, and retardation time were determined based on the experimental and model results. These parameters were observed to follow Arrhenius relationship in the temperature range of 40–70 °C.

Time sweep test (TS) and linear amplitude sweep (LAS) test are the two types of oscillatory shear testing that were commonly used fatigue tests. The damage progress from these both tests is expected to be completely different for different binders. In this study, the fatigue damage due to TS and LAS test is quantified using the evolution of distortion in the Lissajous plot. For this investigation, bitumen of grade VG30 and polymer-modified binder of grade PMB40 (Plastomer) were used. Both the binders were tested in long-term aged condition. The TS test was conducted at 20 °C for 1 and 1.5% strain amplitude at 5 and 10 Hz frequencies for 20,000 cycles. For the LAS test, strain amplitude varies from 0 to 30% at 20 °C and a frequency of 5 and 10 Hz. The Lissajous plot was fitted to the standard ellipse, and the distortion in the shape was measured using the R² value. The fatigue life was identified as a point of slope change in the R² plot. The fatigue life of binder obtained from TS test was found to be 10–40 times higher than fatigue life from LAS test. Also, the fatigue life ranking at different frequencies from LAS test was observed to be different from the ranking obtained from TS test.

Tensile Strength Ratio (TSR) is a moisture-defining characteristic of hot mix asphalt (HMA) used to describe the susceptibility of mix against moisture damage. The goal was to create an artificial neural network (ANN) model that could forecast TSR. Compaction blows, bulk density expressed in gram per cubic centimeter, bulk specific gravity, stability, flow, percentages of bitumen content, air voids, voids in mineral aggregate, and voids filled with bitumen were employed as the predictor variables. Modeling involved these properties of the mix as input parameters and TSR as an output parameter. Feedforward backward type architecture with Levenberg-Marquardt training algorithm opted for the ANN model. The significance of input parameters was based on Pearson’s test (R-value). The results demonstrate that the model is able to forecast the TSR values of a bituminous mixture with high accuracy. Values of performance parameters were observed to be satisfactory (RMSE <1, MAPE <5%, R >0.8, R² >0.75) on validation data. A set of calculating equations have been derived using the best ANN model to measure TSR. The relevance of parameters in forecasting TSR has been determined using Garson’s method. The sensitivity analysis result shows that out of all input parameters, Stability_dry is more effective in explaining TSR (predicted) variations. This study is limited to volumetric properties of the HMA mix and assessment of TSR using ANN techniques.

Timely detection of road cracks is vital for efficient maintenance of road pavements. The conventional road condition assessments involve manual surveys that fail to meet the present-day requirements. Hence, there arises a need to assess the pavement conditions using state-of-the-art technology. The presented work addresses this need and utilizes 2D-digital images of roads. The study considers Sobel edge detection operator and analyzes the performance of its components when used individually vis-à-vis when combined for recognizing road cracks. The main feature of this study is to establish a relation between the type of road crack to be recognized, the type of Sobel component to be used, and the direction and orientation of capturing road images. The study concludes by providing guidelines about which element of a Sobel operator is suitable for highlighting which crack type. The results are beneficial when crack highlighting is required at pixel level to provide more precise information about road damage and its severity.

Accident blackspot ranking criteria in practice, based on accident counts and rates, have deficiencies. A method is formulated here to prioritize the high-risk zones based on an economic criterion for improvements. Stated choice method (SCM) is adopted to find out people’s willingness to pay (WTP) to reduce the probability of being a victim in a road accident. Cost of fatality and injury accidents is arrived through this WTP method. After getting the cost of various severity levels, they are clubbed together according to the severity distribution to calculate cost of different categories of accidents. Total financial impact by a particular blackspot is arrived at by aggregating these values with the number of different category of accidents at that spot, and based on these cost, criteria blackspots are prioritized for safety improvement works. It is anticipated that this study will fill the gaps of the traditional criterion for blackspot ranking.

Fixed route paratransit complements transit service as a feeder mode. These services are offered by private operators without any government subsidy and are loosely controlled via paratransit unions in many countries such as India. Poor service quality of these modes creates barriers in the provision of an integrated transit experience. Thus, there is a need for formal regulatory policies or advisory guidelines to improve their service quality by taking into consideration users’ perception. These policies and guidelines can be developed through determining the Level of Service (LOS) scales for different service quality attributes and then determining their priority so that their shortcomings can be addressed. In this research, we extend our earlier work on LOS scale development to determine the priority of various service attributes and their implications in policy formulations for fixed route paratransit services in Kolkata, India. Further, both stated and derived importance techniques are utilised to ensure the inclusion of service aspects that could be adopted in future. RIDIT analysis is applied to estimate the level of importance of attributes from stated importance data and derived importance is determined using the partial log-likelihood (PLL) technique. Unlike earlier studies, this research highlights that improvement of paratransit service operations can be only achieved through the integrated effort of operators, union authorities, regulatory authorities and city officials.

The transportation system plays a prominent role in the urban spatial structure. It is the main social-economy operation of the city. Transport planning is a complex process requiring meticulous forecasting of potential needs and review of current urban travel trends. Sustainable development is enabled by successful route planning and accessibility. The GIS-based Network Analyst allows users to dynamically model realistic network conditions at various times of the day, including turn restrictions, speed limits, and traffic conditions. A GIS can be used to monitor the transport system, network conditions, the shortest or best route to the destination, and the closest services. The main purpose of this paper is to provide an enhanced road network analysis that uses the capabilities of GIS to identify the fastest as well as the shortest route between the two busiest hubs in Guwahati city. A basemap of the city is downloaded using the QuickMapServices plugin. The network analyses such as routing and nearest facility are carried out in this project using various plugins available in QGIS. The points of origin and destination were chosen to address the network in order to decide the shortest path as well as the fastest path and to serve the purpose of the analysis. The study would raise awareness of the potential for data collection, management, and analysis of geographical information technology. It will allow them to access low-cost technology and freeware solutions to operate in GIS for decision-making purposes. It will highlight the gaps and restrictions impacting the use of GIS in the transport planning field for the responsible offices to deal with.

Two-lane two-way highways constitute a significant portion of road networks in developing countries. Highway Capacity Manuals developed by various agencies suggest the use of performance measures based on platooning of vehicles for evaluating quality of service provided by two-lane highways. Current practices use a single critical headway for identifying the following vehicles but this has its drawbacks. This paper checks the suitability of headway and speed-based probabilistic approach for Indian condition where traffic is heterogeneous and exhibits weak lane discipline. The new method under consideration is compared with current practices by carrying out correlation analysis with 5 min directional traffic flow rate. Analysis showed significantly higher correlation coefficients for the new method compared to that of currently used methods. The method can identify a greater number of vehicles as followers and is also able to account for “happy to follow” vehicles and “safe drivers.”

Transportation planning, which includes identifying the travel demand and implementing plans accordingly, plays a major role in maintaining a balanced urban transportation system. Using travel demand models, alternative socioeconomic scenarios and land-use scenarios can be modeled to estimate travel characteristics for the future. The continued growth of cities results in infrastructure developments and increased employment opportunities, thereby increasing the travel demand and consequently causing traffic and transportation problems. The importance of studying the trip generation pattern is therefore highly warranted. The present paper attempts to identify the factors that influence the trip attraction potential for the core region of Thiruvananthapuram city, the capital of Kerala, India. The attraction characteristics of various establishment types are determined by the development of trip attraction models. The models developed have shown that the trip attraction is dependent on the number of employees, floor area, and parking space.

Transit Oriented Development (TOD) has emerged as an essential planning tool for transport planners around the world. The promising results expected from TOD can only be materialized if the frameworks for its implementation are in place. This study is an attempt to address a part of this gap by analyzing the concept of TOD in the Indian context and developing a methodology for the initial selection of sites. The selection of sites that has the potential to be developed as a TOD was conducted using the Geographical Information System (GIS) analysis for the case city of Kolkata. The analysis is based on factors like growth centers, population density, transportation network, metro rail ridership, and experts’ opinion. Two different types of sites, namely, ‘Esplanade’ and ‘Newtown/Rajarhat’ were derived from the proposed methodology. The study concludes by critiquing these sites based on spatial analysis and secondary data.

Public private partnerships (PPP) in urban bus services are looked at as an instrument for breaking the vicious cycle of undersupply, degrading quality of city bus services and consequently increase in cost. Though feasible, the full potential of PPP models remains unexplored due to lack of appropriate ecosystem and an enabling environment to ensure the success of PPP. The paper identifies the ecosystem for the sustainable implementation of PPP in city bus system with a tool to objectively assess the preparedness of the cities. Through review of successful cases and consultations, it establishes the parameters of an enabling ecosystem comprising of policy and regulatory framework, funding framework, contractual framework, infrastructure framework and public institutional framework. These parameters are ranked and weighted by the stakeholders—policy makers, states/cities/state transport units (STU)/special purpose vehicles (SPV), academic experts and consultants as well as private operators and manufacturers. A multi-criteria decision-making technique, i.e. “Analytical Hierarchy Process” (AHP), has been used as tool for the research paper. According to the research findings, sustainable funding has been rated as the most important parameter followed by policy and regulatory framework while infrastructure framework rated as least important. The assessment and weightage assigned are useful to policy makers, cities and private operators to enable them to assess risks before partnering with any city. It also ensures safe “returns on their investment” as well as success of PPP in the city undertaking the same.

Excessive traffic during peak hours in the Central Business District (CBD) of a city can be reduced by successfully implementing congestion pricing. This paper estimates congestion pricing duration and its benefit in terms of reduced traffic volume, hence reduced travel time in an urban corridor of Kolkata. Using videography method, traffic flow data are extracted whereas for travel time data, Google Maps is used. These data are used to find temporal variations of flow as well as travel time, and it is observed that flow varies with the square of travel time. Users were interviewed, and preferential study was conducted in order to find the willingness to pay in a hypothetical condition of congestion pricing, introduced in that particular corridor. Now, users’ willingness to pay, shift to public transport or shift to a different time window has been calculated using multinomial regression technique. The results show that optimum pricing duration, i.e. maximum reduction in flow, is observed from 9 to 11 am in the morning peak and from 4 to 7 pm in the evening peak, and the corresponding flow reductions are around 18% and 30%, respectively. An optimum pricing level of ₹15 is calculated using weighted average method. This approach may be adopted to determine the pricing levels, duration and benefits of congestion pricing to other corridors with similar traffic characteristics. If user perceptions are not considered, flow reductions and improvement travel times are even higher, but large number of commuters have to unwillingly shift their trip time. Therefore, this study also highlights the percentage of trip maker who will have to unwillingly shift their trip time to improve the overall travel time due to the congestion pricing.

This study evaluates and compares two major solutions used to mitigate the problem of delay of public transport buses at signalized intersections in urban arterials. The solutions considered are to implement bus signal priority (BSP) at intersections and to provide dedicated bus lanes (DBL). Comparison of performance is done in terms of travel time. Study site selected is a 5 km stretch in the IT corridor in Chennai for the DBL and with four intersections in that corridor for the BSP. Only the southbound movement is considered for the analysis. To evaluate the selected strategies, the study site was simulated in VISSIM, which is a micro-simulation software. Road, traffic, and control details from field were used as input, and a calibrated network was created. Using that, four scenarios were studied: 1. base condition with fixed time signals and no dedicated lane, 2. fixed time signal with DBL, 3. BSP without dedicated lane, and 4. BSP and DBL. Conditional Green Extension and Red Truncation priority strategies using Visual Vehicle Actuated Programming (VisVAP) from VISSIM were used for the BSP implementation. For dedicated bus lane condition, the mode preference was altered for the southbound movement links and the bus movement was allowed only in the left-most lane, which was kept as DBL. Results showed the bus signal priority having maximum impact in terms of reduction in total travel time. In the case of dedicated bus lane condition, travel time reduced effectively for bus mode, but with an increase in travel time of other modes.

Period-wise bus frequency setting and timetable development for full-day operations are important for intercity bus service design along a particular route. Service design based on user perception and expectation of service attributes like crowding level, waiting time, etc. are important in maintaining the attractiveness of the service. The levels of these service attributes are responsible for determining the service cost of full-day bus operation. User cost components consist of in-vehicle travel time in crowded conditions, waiting time, whereas operator costs include vehicle capital cost, maintenance cost, running cost, and costs resulting from passenger loss. Thus, minimum social cost, i.e., combined user, and operator cost is crucial to make bus transit an attractive, affordable, and viable mode for catering to the passenger travel demand. Intercity service also requires a dedicated fleet both due to the nature of the service as well as bus type which are suitable for long-distance highway travel. In this research, we determine period-wise bus frequency, timetable, fleet size for the Greater Raipur region (GRR) along the 51 km long route connecting Raipur and Durg. Genetic algorithm (GA) has been utilized for optimization of service level parameters where the fitness function is the minimization of the social cost of running a full-day bus service in both directions. The model is used to generate the timetable and estimates the minimum fleet size as 14 buses.

Public transport planning is one of the most important criteria in the development strategy of any country. India is a developing country, and the smart card facilities are rare; hence, it is suitable to look upon easily available data sources which could be helpful for public transport planning. One such big data source is the electronic ticketing machine (ETM) data. This study focuses on the long-distance bus services operated under Kerala State Road Transport Corporation (KSRTC) in Thrissur district, Kerala. KSRTC has been identified as one of the major losses making public sector services according to the Shushil Khanna Panel report. In order to improve the situation, a study on the existing conditions was essential. This study explores the use of ETM data in the generation of origin destination matrix for the long-distance bus services. The ETM data of the long-distance routes maintained by KSRTC has been collected from all the five bus depots in Thrissur. An algorithm has been developed which defines the sequential procedure followed to get the desired matrix output. Based on the developed algorithm, a Python code has been framed so as to estimate the origin destination matrix. The network model was created in VISUM, and desire line and flow bundle analysis has been carried out based on the consolidated OD Matrix in VISUM. The analysis found out Thiruvananthapuram to Attingal as the OD pair with maximum demand and the route sections that are contributing to the loss in the sector has been identified.

In developing countries like India, number of people using public transport for everyday commute is large. Trip planner is a tool which helps commuters to plan their travel beforehand. In case of public transportation systems, trip with the minimum travel time is often of interest. A trip planner solves the time dependent shortest path problem (TDSPP) in a multimodal transport network to optimize one or more criteria like travel time, the number of transfers, etc. One subclass of this is the departure time planner. It suggests the optimal departure time from origin such that travel time to reach the destination will be minimum. This paper presents development of multimodal departure time planner using General Transit Feed Specification (GTFS) data. A citywide public transportation network is constructed with bus, metro and walking as modes of transport. Nodes represent transit stops and edges represent transportation services available in between nodes. The schedule corresponding to every mode is incorporated in the network. Origin, destination, and the latest arrival time at the destination for the trip are inputs from the user. A schedule-based algorithm is implemented which runs backward in time to calculate optimal labels at every node of the network. The results produced by the trip planner are found to be promising in terms of accuracy and feasibility.

Mass rapid transit or metro rail systems have an edge over other public transportation systems because of their reliability, comfort, and safety offered to passengers. This paper presents a statistical analysis of ridership of Bengaluru Metro rail (BM), which in March 2018 had two lines, 40 stations, and an overall length of 42.3 km. The daily and hourly temporal variations in ridership are analyzed. Spatial distribution of ridership is studied to understand weekday and weekend trip patterns. Three influencing factors—(i) availability of parking at metro stations, (ii) the presence of transport hubs nearby metro stations, (iii) distance to the nearest intra-city bus stop from metro station are considered. Their effect on footfall at stations is studied with the help of a panel data model. Further, a procedure to estimate savings in emissions due to the metro rides is described. Estimated savings in CO, HC, NO_x emissions are 5.19, 0.54, and 0.66 tons per day, respectively.