Discussion on (Identifying Areas Of) Research in Transportation

Discussion on (Identifying Areas of) Research in Transportation

Final Report

Compiled by:

Partha Chakroborty, Ph.D. Vinod Vasudevan, Ph.D., P.E. Animesh Das, Ph.D. Syam Nair, Ph.D.

Department of Civil Engineering Indian Institute of Technology Kanpur Kanpur, UP 208016

Sponsored by: Department of Science and Technology Government of India

Hosted by: Indian Institute of Technology Kanpur

Introduction Indian Institute of Technology Kanpur hosted a workshop titled “Discussion on (Identifying Areas of) Research in Transportation,” sponsored by the Department of Science and Technology, Government of India on November 7, 2014. The purpose of the meeting was to identify important areas of research in transportation engineering. Twenty one participants from various academic institutions, research organizations, consulting organizations, and industry participated in this workshop. The list of participants (along with their affiliation in parenthesis) is as follows: Prof. A. Veeraragavan (IIT Madras) Prof. Akhilesh Maurya (IIT Guwahati) Major Alok Mohanty (Border Roads) Prof. Animesh Das (IIT Kanpur) Prof. Ashish Verma (IISc, Banglore) Prof. B. B. Pandey (IIT Kharagpur) Dr. Devesh Tiwari (CSIR - Central Road Research Institute) Prof. Geetam Tiwari (IIT Delhi) Prof. Gopal Patil (IIT Bombay) Dr. Harikishan K. Reddy (VR Techniche) Dr. P. K. Jain (CSIR - Central Road Research Institute) Prof. P. K. Sikdar (ICT Technocrats, Pvt Ltd) Prof. Partha Chakroborty (IIT Kanpur) Maj. R. R. Deshpande (Border Roads) Dr. S. Velmurugan (CSIR - Central Road Research Institute) Prof. Sanjay K. Singh (IIM Lucknow) Prof. Satish Chandra (IIT Roorkee) Prof. Syam Nair (IIT Kanpur) Prof. Tom Mathew (IIT Bombay) Mr. V. K. Singh (UPPWD) Prof. Vinod Vasudevan (IIT Kanpur)

Other than the above participants, Prof. Karthik Srinivasan of IIT Madras gave his inputs via email. This report lists the topics identified in this workshop along with brief description on each of them. Note that each of these topics could lead into more than one research project. 1

Potential Research Topics in the Areas of Traffic Engineering, Travel Demand Forecasting, and Transit Systems

Title: Understanding pedestrian crossing behaviour for developing warrants for different types of crossing facilities Brief Description : Studies need to be conducted on how pedestrians behave on roads (at intersections, mid-blocks, near public-transit stops, etc.) especially when crossing them. The study should throw light on gap-acceptance behaviour of pedestrians as well as the trade-off they make between their safety and ease of crossing. The outcome from such studies may include, among other things, (i) hypotheses on pedestrian crossing behaviour and (ii) volume warrants for zebra, signalized, and pelican crossing as well as subway or FOB. Title: Understanding pedestrian behaviour in (primarily) longitudinal flow for design of pedestrian facilities Brief Description: Studies need to be conducted on how pedestrians behave while moving along roads (footpaths, shoulders, etc.) The study should throw light on flow parameters of such pedestrian streams as well as the trade-off they make between their safety and ease of mobility. The outcome from such studies may include, among other things, (i) hypotheses on pedestrian stream behaviour (including capacity and level of service) and (ii) design parameters for road- side pedestrian infrastructure. Title: Understanding pedestrian behaviour in heavy flow condition Brief Description: Studies need to be conducted on how pedestrians and groups of related pedestrians behave at high densities (for example, at transit stations, special event gatherings like Kumbh-Mela, sports grounds, etc.) during normal scenarios and under panic situations. The outcome from such studies may include, among other things, (i) hypotheses on pedestrian stream behaviour and (ii) design parameters for pedestrian facilities, and (iii) evacuation strategies, etc. Title: Understanding bicycle traffic behaviour/characteristics Brief Description: Studies need to be conducted on (i) bicycle stream behaviour, (ii) bicycle crossing behaviour, (iii) bicycle and motorised vehicular stream interactions, and (iv) bicycle and pedestrian interactions. The study should throw light on flow parameters of such pedestrian streams as well as the trade-off they make between their safety and ease of mobility. The outcome from such studies may lead to design parameters for road-side bicycle infrastructure. Title: Developing an automatic traffic counter-cum-classifier for Indian mixed and disorderly traffic Brief Description: Indian traffic streams differ from traffic streams in US, Europe, etc. (where such instruments were designed) in the following ways (i) traffic is not lane based in India, and (ii) extreme heterogeneity in traffic streams in India creates large speed differentials and varied vehicle types. Hence there is a need to develop instruments that can handle these differences and still provide accurate vehicle counts by classes.

Title: Characterizing non-lane based mixed traffic flow and developing macroscopic traffic flow models Brief Description: Indian traffic streams differ from traffic streams in US, Europe, etc. (where most traffic flow studies were done) in the following ways (i) traffic is not lane based in India, and (ii) extreme heterogeneity in traffic streams in India creates large speed differentials and varied vehicle operating characteristics. Hence there is a need to develop a different view of the traffic stream parameters as well as develop fundamentally different models of traffic flow. For example, while lateral interactions in lane base traffic streams are episodic, in Indian streams such interactions are present at all times. Therefore, while 1-D models of traffic flow might suffice for lane based traffic, one needs 2-D stream models for Indian traffic. Title: Modelling driving behaviour for non-lane based mixed traffic (microscopic models of traffic flow) Brief Description: Indian traffic streams are unique in that (i) the traffic is not lane based, and (ii) the heterogeneity in traffic streams is high. The non-lane based nature implies that one needs to understand and model both lateral and longitudinal placement behaviour of Indian drivers. The heterogeneity requires that such models be sensitive to the types of vehicles in the immediate vicinity of the modelled driver. In a way the need is to develop models that integrate both car-following and lateral placement behaviours. Overtaking behaviour in such streams also needs to be studied. Research also needs to be carried out to predict macroscopic behaviour from these microscopic models. Title: Developing methodology for estimation of flow equivalency in uninterrupted and interrupted flow conditions Brief Description: Owing to the extreme variability present in Indian traffic streams (due to the large variations in vehicle operating characteristics and no lane discipline) concepts like passenger car equivalency needs to be revisited and redefined for Indian conditions. Title: Understanding flow through signalised intersections Brief Description: Research needs to be carried out to understand the factors that impact arrival processes (arrival distributions, progression factors, etc.) and departure processes (lost times, saturation flow, etc.) at signalized intersections. Effect of phasing schemes on safety and efficiency of such intersections also needs to be studied. Work on ideal cycle lengths at intersections also need to be carried out. These studies may ultimately lead to Indian design guidelines for signalized intersections. Title: Understanding flow through unsignalised intersections Brief Description: Research needs to be carried out to understand the factors that impact arrival processes (arrival distributions, etc.), departure processes (gap acceptance, merging, etc.) and stacking process (where waiting vehicles often occupy opposing lanes) at unsignalized intersections (including T-intersections). Queuing models for such intersections need to be developed. Such models should be able to estimate queue and delay distributions. Impact of channelization on flow at such intersections also needs to be studied. The studies conducted can also lead to realistic simulation models. Title: Identifying methods to predict travel time for real time applications Brief Description: With the proliferation of faster and cheaper communication devices road users as well as system planners can now benefit from real-time information on the travel 4

times on various parts of the network. Algorithms that can make reliable travel-time predictions are therefore the need of the day. Research on developing algorithms that (a) work on various data sources (like, (i) speed, flow, occupancy data from static devices, (ii) probe vehicle (automobile) data, (iii) data from trucks and buses, etc.), (b) require different extents of computation, and (c) provide varying tradeoffs between accuracy and computational effort needs to be carried out. Studies on how such methods can be used to identify congestions on a network are also required. Title: Developing area-wide traffic control algorithms/strategies Brief Description: Algorithms/strategies that can influence various traffic control measures (like, signal timings, coordination, bus priority, lane reversals, ramp meters, etc.) in order to reduce system (area-wide) travel times need to be developed. Such strategies must be sensitive to the way transport demand reacts to various traffic and control features. Title: Studying effect of geometric design on flow on highways Brief Description: Research to develop an understanding on (a) operational effects of highway geometry, (b) highway geometric design consistency parameters, and (c) safety impact of various combinations in highway geometry feature (i.e. horizontal curve, vertical curve, grade, super elevation, presence of median, etc.) for heterogeneous traffic with weak lane discipline are required. Title: Studying the effect of vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications on safety and mobility in Indian traffic streams Brief Description: V2V and V2I communications have the potential to fundamentally alter driving and traffic behaviour. They have implications on safety, mobility on road segments and at intersections (locally and at network level), emissions/energy, etc. Studies that throw light on how such communications impact safety and mobility need to be carried out. Title: Developing algorithms towards the realization of autonomous vehicles Brief Description: There is tremendous interest in moving from driver assisted systems to completely autonomous vehicles. Within the next decade autonomous vehicles may be sharing the roads with conventional driven vehicles. They have significant implications on throughput of road network and on safety. Several methodological issues like self-learning driving algorithms under different situations such as free-flow conditions, congested conditions, stop-and-go traffic, intersections, etc. need to be sorted out before their wide- spread use.

Title: Understanding costs of Indian road accidents Brief Description: For any engineering and planning decisions related to traffic facilities one needs to understand the individual and social costs of various types of road accidents. In order to do so, socio-economic and demographic characteristics of accident victims in India and relation between nature of accidents and wage and lifestyle loss need to be established. Models of social costs of accidents need to be developed. Title: Developing road safety measures Brief Description: Studies on developing road safety measures that reduce the frequency and severity of road accidents need to be carried out. The issue is complex as (i) the effectiveness of such measures often depends on human perceptions of their efficiency and need, (ii) the impact of such measures on different vehicles and their users are different, and (iii) they may 5

affect traffic flow in such a way that mobility is affected and other unsafe situations are created. The cost of such measures (including impact on traffic, installation and maintenance expenses, etc.) and benefits also need to be evaluated realistically. Research on determining crash modification factors for various safety measures under Indian conditions also need to be developed. Title: Understanding the cost of transportation on urban/rural roads Brief Description: Cost of transport includes (i) construction, maintenance and operation costs of the transport facilities, (ii) vehicle operating and maintenance costs, (iii) time/delay costs to the users, (iv) accident costs, and (v) environmental cost. One needs to understand the elements that contribute to these costs and how these costs can be brought down. It may be noted that often the elements of the transportation facility impacts more than one type of cost. Title: Understanding the impacts of fuel policy on cost of transportation Brief Description: Fuel policy impacts the cost of transportation in varied ways. For example, it has impact on vehicle technology, vehicle cost, operating cost, environmental costs, etc. The fuel policy may even impact modal splits in urban scenario. Mathematical structures that can be used to understand the various effects of fuel policy on the transportation system need to be developed for Indian conditions. Such models can be used to identify efficient fuel policies for India. Title: Developing surrogate measures to understand risks to road users Brief Description: Crash data provide a good assessment of traffic safety of a location or region. In the absence of reliable crash data, as in India, it is important to look for surrogate measures (based on geometric features, flow characteristics, etc.) that indicate traffic related risks. Research on identifying surrogate measures and their effectiveness needs to be conducted. Traffic safety studies also include risks to pedestrians and NMT users. Title: Developing transit routing algorithm Brief Description: The transit routing problem is a difficult optimization problem. Efficient optimization methods need to be developed so that good transit route sets for large cities and networks can be developed. Further, the constraints within which such route sets have to be developed vary from one network to another and vary with the nature of service. Title: Developing transit scheduling algorithm Brief Description: The transit scheduling problem is a difficult optimization problem. Efficient optimization methods need to be developed so that good transit schedules for large cities and networks can be developed. Further, the constraints within which such schedules have to be developed vary from one network to another and vary with the nature of service. Ideally, transit routes and schedules should be developed concurrently. This further complicates the optimization problem. Innovative algorithms for such problems are required. Title: Developing vehicle assignment algorithm Brief Description: Once routes and schedules of transit systems are developed, the operator needs to assign the fleet to these routes. Since, fleet is invariably limited algorithms that efficiently allocate the fleet are required. Often, different public transit modes have different restrictions (on maintenance requirements, maximum travel distances of vehicles, etc.) that have to be incorporated in the vehicle assignment process.

Title: Developing crew assignment algorithm Brief Description: Once routes and schedules of transit systems are developed and the fleet assigned, the operator needs to assign the crew to these vehicles operating on different routes. Since, crew is invariably limited algorithms that efficiently allocate the crew are required. Often, different public transit modes have different restrictions on crew expertise, working hours and associated labour laws, etc. that have to be incorporated in the crew assignment process. Title: Developing comprehensive transit planning algorithm Brief Description: Although, the transit planning task can be divided into a set of four tasks (routing, scheduling, vehicle assignment and crew assignment) to be implemented sequentially it is clear that the solutions obtained from such a set of processes will be sub- optimal. More efficient solutions can be obtained if these processes are integrated into a single comprehensive optimization formulation. Even if complete integration is not possible attempts to integrate some of them (like vehicle and crew assignment or scheduling and vehicle assignment, etc.) are worthwhile exercises. Title: Understanding the relationship between urban geography and public transportation Brief Description: Different public transportation systems are available. Research on relating the spatial and demographic characteristics of the urban area to the type of public transportation options appropriate for that area needs to be carried out. Further, currently there is no clarity on how to choose and integrate different transit modes (like light rail transit, bus rapid transit, bus network, para-transit, etc.) into a city’s or region’s transportation system. Studies in such areas need to be conducted. For example, studies on (i) appropriate share of intermediate public transit (para-transit) in a city’s transportation infrastructure (ii) the necessity of separate right-of-way public transport systems, etc. are required. Title: Understanding the dynamics of land-use and transportation Brief Description: How land-use and transportation impact one another in India need to be understood. Such understanding will lead to arresting urban sprawl, unsustainable development, etc. Title: Understanding the choice of vehicle type for freight transportation Brief Description: In India freight transport on roads takes place in various types of vehicles. Research on the impact of factors such as trip length (intercity and intra-city), type of commodity, urban form, distribution network, and regulatory frameworks (time of entry in city) on the choice (by transport providers) of freight vehicle type and size needs to be conducted. Such research will help estimate the commercial vehicle traffic demand on city roads. Title: Developing freight demand models Brief Description: Models that predict Indian freight demand are still in their infancy. Research on quantification of demand (trips, ton-km, etc), freight demand generated, interaction among shippers, receivers and carriers, etc. should be carried out in order to develop good demand models.

Title: Understanding the impact of information and communication technologies (ICT) on travel behaviour and transport efficiency Brief Description: The way ICT impacts traveller behaviour is different for different cultures. It is also dependent on the processes used to arrive at information that gets disseminated in the population. How people react to the information also impacts the efficiency with which the transport system works. Studies specific to the Indian traveller needs to be conducted to understand how they behave with respect to information on network status and route and departure-time advisories. Title: Understanding user choice behaviour mechanism Brief Description: Currently the user choice behaviour is modelled assuming that users maximize utility. There is a need to understand if the users really maximize utility or there is a different paradigm like minimizing regret or are prospect theory based models better descriptors of the user choice process in transportation. Impact of the effect of habit, inertia, captivity on choice processes also need to be studied. Title: Understanding travel behaviour of NMT (Non-motorized transportation) users Brief Description: NMT users view connectivity between locations differently than motorized vehicle users because the travel speeds and perceptions of safety and security are very different. Hence the travel behaviour pattern of NMT users (more so for captive NMT users) are different. Since India has a large proportion of NMT users it is important that their travel behaviour is studied. Title: Studying the applicability of marketing strategies on public transport demand Brief Description: Can theories of marketing and consumer behaviour be applied to modify the demand for public transport? Case studies and other research tools need to be identified to answer this question. A better understanding of how users can be motivated to remain with public transportation is important to ensure that India does not become an automobile- dependent nation. Title: Studying pricing policies and subsidy requirements for public transit systems Brief Description: Understanding the willingness to pay for different aspects (like travel time reliability, comfort, security, etc.) of public transport systems plays an important role in deciding out-of-pocket cost to its users. The role of pricing strategies on viability of public transport systems, the role of public transport as a social welfare scheme, strategies to improve the quality and competitiveness of such systems, etc. needs to be studied. Title: Understanding paratransit modes and their users Brief Description: Para-transit still plays an important role in most Indian cities and mega- cities. The trip characteristics of para-transit users are different than transit or rapid-transit users. Studies on trip characteristics of such users need to be conducted in order to develop efficient public transport systems. Title: Studying travel behaviour during emergencies Brief Description: Travel behaviour during emergencies/calamities where the primary intent of travellers is to avoid imminent danger is different. Such studies help plan emergency responses and evacuations better. Hence, such studies are important especially for these areas that are prone to natural disasters.

Title: Understanding trip making behaviour of Indians Brief Description: Trip making behaviour of different peoples around the world are different. Trip making behaviours of people from different socio-economic strata, from different regions, from urban versus rural areas, etc. are different. Hence, studies on trip making behaviours of Indians from different social and economic groups, non-workers, women, children, senior citizens, etc. need to be carried out. Title: Studying innovative travel behaviour data collection techniques and their reliability and accuracy Brief Description: Data collection on travel behaviour at a disaggregate level is a challenge. The advances in GPS technology and proliferation of smart phones have provided an opportunity to collect such data from large number of users. Sensor technologies have also improved. How data from these sources can be used effectively in travel behaviour data collection needs to be studied. Development of appropriate toolboxes and methodology to mine and model data from these sources is a promising area for further investigation. Several applications that may benefit from such methodologies include: micro-estimation of origin- destination demand, evacuation planning under natural disasters (hurricane, earthquake), development of on-demand public transport services, operational improvements such as bus route rationalization/ real-time dispatching policies etc. Title: Understanding toll-lane choice behaviour at toll plazas Brief Description: Toll plazas are a necessary evil on expressways. They interrupt traffic on expressways --- roads built to provide uninterrupted flow. Yet they are needed to make expressways viable. One therefore needs to design toll plazas properly. One of the main ingredients to analysing the queueing at such facilities is to understand how arriving vehicles choose a toll-lane queue. Studies need to be conducted to model this behaviour at toll plazas. Title: Studying lane choice (lateral placement) behaviour on multilane roads Brief Description: It is observed that not all lanes of a multi-lane facility are used to the same extent. This differential usage has impact on pavement design and maintenance costs. Studies need to be conducted to see how lane usage depends on vehicle type, vehicle mix, number of lanes, road side developments, etc. Models of lane utilization need to be developed. Title: Understanding route choice behaviour in uni-modal and multi-modal transit systems Brief Description: Transit routes are developed based on assumptions on how transit users choose routes. Studies need to be conducted in Indian cities and towns to understand how factors such as access-egress distance, transfers, frequency, travel-time reliability, comfort, seamless ticketing, security, etc. affect route choice behaviour for Indian users. Models of such behaviour also need to be developed. Title: Developing dynamic traffic assignment (DTA) models Brief Description: The dynamic traffic assignment problem determines the spatial and temporal distribution of traffic arising from individual decisions on vehicle type, route, departure time and destination. Understanding the network wide impact of individual decisions requires DTA models and algorithms to solve the models efficiently. Research is required both on the supply side (network loading methods) as well as on the behavioural assignment side.

Title: Understanding impacts of travel and driver behaviour on emissions, energy consumption and health Brief Description: Trip making behaviour, including trip-chaining patterns, mode choice, route choice, etc. and driver behaviour in terms of acceleration noise, idling, etc. have an impact on emissions and energy consumption and consequently on health. Understanding this relationship in India is important. Title: Determining the value of sustainability and other attributes in users’ travel decisions Brief Description: There is an imminent need to understand whether and to what extent do sustainability related objectives influence user’s selection of short-term choices such as mode, route, and departure time as well longer-term choices such as location and vehicle ownership decisions. While it is well understood that factors such as unreliability, safety, energy consumption, and emissions influence day-to-day travel decisions of users to varying degrees, they remain to be systematically quantified in travel demand and transportation planning models. For instance, while the value of travel time and out-of-vehicle time are systematically analyzed, the value of reliability, emissions, safety and fuel consumption and their part worth utility have received scant attention. A systematic quantification of the role of these factors will pave the way for identification of suitable policies and strategies to promote sustainable and inclusive transportation planning. In fact, such quantification is a preliminary step to sensitize users about the environmental and energy impacts of their travel choices. In addition, research in this regard will be critical for including sustainability metrics as an important part of evaluation and prioritization of infrastructure decisions. Title: Studying choice set and consideration set for various travel decisions Brief Description: Travel demand models used in transportation planning literature in the Indian context have mainly focused on travel mode choice, and only to a lesser extent on route, departure time, or destination choices. The latter two dimensions have received negligible attention but are increasingly important as they directly affect the temporal and spatial distribution of users and traffic on urban networks. Although, the mode choice decision is relatively well studied using conventional discrete choice theory, they have typically been based on restrictive assumptions about the choice set considered by decision makers (homogeneous choice set, or explicit unavailability of some modes such as personal vehicles etc.). However, from a behavioural standpoint, the actual set of alternatives considered by users may depend on the decision-maker’s awareness, attitude, expectation, perception and experience with various means of travel under varying contexts. Fundamental questions regarding the nature of consideration set (such as whether they are latent to the decision maker, and how best they can be quantified - fuzzy or probabilistic framework, basis for consideration - compensatory, non-compensatory, semi-compensatory decision rules) remain to be investigated rigorously. Very little estimation of departure time, route and destination choice models have been reported with real-world data for Indian cities. The formation of choice set particularly for route and destination choice is important given that only the chosen alternative is observed whereas the others are inferred by analyst using sampling techniques with a fixed size of the choice set across users. The extent of bias, and inferential power of such assumptions remain to be verified and the implications for forecasting and policy evaluations need to be quantified in relation to scientific and empirically grounded models of choice set formation. This needs to be studied in detail in Indian scenario.

Title: Understanding intra-household interactions and time-space constraints in activity and travel decisions Brief Description: Travel decisions such as mode, route, destination, vehicle ownership, and residential location choices may be influenced by interactions among different household members. Conventional four-step models have often been criticized for disregarding such interactions. These interactions may be directly manifested in choice process, for instance, in the case of joint activity participation and joint travel decisions. In other cases, the interactions may constrain the choice process through allocation of resources (such as vehicles), time, and travel cost budget. These household interactions can lead to complex substitution and generation patterns across and within individuals in a household both in terms of activity participation and the derived travel decisions. Disregarding these interactions by assuming independence can lead to less behaviourally realistic models of travel demand and can trigger erroneous policy evaluations. Further, the presence of time-windows and spatial constraints associated with activities of some members may result in changes or elimination of activity and travel decisions of other members. To ensure the development of causal, behaviourally-based, and policy sensitive models, there is a need to explicitly represent time-space constraints and capture intra-household interactions between activity and travel decisions. Title: Understanding traveller responses to various means of multi-modal integration Brief Description: There is increasing focus on promoting multi-modal transportation systems to tackle the urban challenges of congestion, pollution and road safety. While public transport systems have an important role in this regard, non-motorized modes and IPT (intermediate public transport) may also play an important role in this context. Several opportunities are available to promote multimodal integration. These include but are not limited to: last mile connectivity through better access, transfer facilities, physical access to terminals, ease of boarding and alighting different means of transport, intermodal dependencies (e.g. Effect of walking safety and footpaths on transit use), possibility of increasing time use productivity during travel and while waiting, reduced uncertainty through real-time information (e.g. Bus or train arrival time), promoting use of personal vehicles and parking management to increase accessibility/influence areas for transit modes, integrated operation and ticketing strategies. However, there is very limited knowledgebase on how effective (separately and collectively) each of these measures would be in inducing desirable modal shifts towards public transportation. In fact, at a fundamental level, there is a lack of understanding regarding the extent of disutility associated with transfers and whether such a disutility may at all be compensated by improvements listed above. Traveller’s perception of multimodal choices and evaluation of associated factors need to be investigated in the light of contextual factors such as the presence of co-passengers, children, carrying luggage or heavy items, and weather, in addition to usual level-of-service attributes. Title: Understanding user tolerance and responsiveness to congestion and impact of congestion charging and pricing policies Brief Description: Growing congestion in urban areas is leading to severe adverse impacts on mobility at the individual level and economic growth and productivity at the societal level. Despite the growth in congestion, the rate of motorization continues to grow and the mode share of personal vehicles is also increasing in several Indian cities. This begs the question as to whether the choice of personal vehicles and their use is fuelled by ‘greater mobility’ offered by personal means of travel and whether there is a limit to the tolerance of personal vehicle users to the magnitude of congestion. In contrast, some public transport modes which

are also subject to congestion face a greater decline in mode share. Thus, the social and equity impacts of congestion are not well understood. At the same time, several cities around the world are considering imposing congestion charging and pricing policies to tackle congestion and its consequences. The relevance and potential impacts of such policies and how they may be implemented in Indian cities needs to be examined rigorously. In this regard, the relative sensitivity or lack of thereof to congestion faced by personal vehicle users, and the differential impacts on different mode classes need to be investigated. User response to and prospects for mitigating congestion by vehicle occupancy based measures through managed lanes such as High occupancy vehicle lane and High occupancy toll lanes, Bus Rapid Transit, shared vehicle models etc. remain to be studied systematically. Title: Developing Inter-city passenger travel demand models Brief Description: The inter city travel demand markets are witnessing dramatic changes due to the growth in airline industry over the last decade. In comparison, the rate of growth in railway services has been lower but its network coverage wider and capacity is larger. The differential in speed and significant increase in business related travel are also changing mode shares. Compared to the urban mode choice analysis, very limited attention has been given to inter-city travel demand models. Many models have relied on mode-wise aggregate demand forecasting frameworks that are based on distinct market assumptions. But with the plans for introducing high speed rail, the two may be direct substitutes in some cases, and complementary in others. The lower travel times may induce travel that hitherto may not have been performed. There is a need for a detailed investigation of determinants of intercity travel demand models specifically in the light of designing suitable infrastructure capacity, location decisions of hubs/spokes and transfer facilities, as well as pricing and operational decisions. Title: Understanding methodological issues related to travel behaviour modelling Brief Description: The availability of new sources of travel demand and behavioural data such as GPS and smartphone (together with conventional travel diary surveys), presents unique opportunities to model travel decisions at a very disaggregate level and high level of spatial and temporal resolution. These include: selectivity bias, heterogeneity in behaviour, endogeneity or reverse causality among multiple travel dimensions (e.g. Vehicle ownership and trip frequency, mode choice and vehicle ownership, mode choice or joint/solo travel etc.), dynamic effects such as state dependence (probability of being in a state or making a choice causally depends on the prior state, history or evolutionary path), habit persistence (lagged influence of experiences and explanatory variables in the past), inertia, search and switching cost, learning and fatigue effects, and temporal correlations as well as spatial dependence (similarity or dependence of responses of spatially proximate units) and spatial heterogeneity (response or preference sensitivity may vary across spatial units such as analysis zones). Disregarding these effects when present can not only distort model forecasts (and at times may be masked as other effects such as random effects), but can also lead to the choice of sub-optimal or inadequate policies. However, the incorporation of these aspects necessitates the development of appropriate models, identification conditions, parameter estimation techniques, and model selection criteria. Title: Modelling vehicle ownership in India Brief Description: It is important to study the factors that affect vehicle ownership in both urban and rural India. Presently lack of extensive and reliable household-level data pose a challenge in developing good models of vehicle ownership. Hence, good data on vehicle ownership needs to be collected and used to develop choice models.

Potential Research Topics in the Area of Pavement Engineering

Title: Characterizing bituminous binders and identifying relation between binder properties and performance Brief Description : Bituminous binder is an essential ingredient of bituminous mix, used for construction of surfacing, binder and base course of flexible pavements. The performance of bituminous binder and mixes are influenced by its composition, rheology of binder and the preparation process. The performance of modified binder depends on the type and dose of additives used for binder modifications. The physico-chemical properties of the binders play a vital role in deciding its performance of the pavement commemorating to ageing, fatigue cracking, rutting and so on. Fundamental research is needed to understand the physical processes involved. Title: Developing test protocol for characterizing ageing of bituminous binder Brief Description : Bituminous binder gets aged while it is exposed to the environment. The ageing of binder is a complex process, which eventually causes degradation of the physical properties of the binder. Research is needed to understand the physico-chemical process involved in binder ageing and subsequently develop advanced test protocols to characterize (field and laboratory) ageing of binders. Title: Studying alternate binders for pavement construction Brief Description : While bio-fuels are generated from plants and other biological sources, bio-binders automatically evolves as a by-product of the process. Given the increased cost of procurement of bitumen, use of bio-binders are emerging as an alternative binder for road construction. Different types of bio-binders need to be characterized and their efficacy in road building applications needs to be studied. Title: Developing test methods and models for fatigue and fracture of bituminous mixes Brief Description : Bituminous mix is a complex material - it does not behave like a linear, elastic, isotropic, homogenous material. Its response also changes significantly with the change of temperature. Further, under certain conditions, cracks formed in bituminous mix may get healed up. Therefore, understanding the phenomenon of fatigue and fracture in bituminous mix is a challenging task and necessitate fundamental research. The knowledge gained through this research can be utilized in design and construction of good roads that will possibly not fail prematurely. Title: Studying inter-relationship between aggregate and binder surface energies on the moisture damage of bituminous mixes Brief Description : The aggregates used in road construction may have different surface charges (electropositive, electronegative or neutral) depending on the source. Bitumen is a mildly polar material. It is interesting to study how bonding develops between aggregates and bitumen for various types of aggregate-bitumen combinations. Also, study needs to be done on understanding of moisture damage of bitumen under static and dynamic conditions with aged and un-aged bitumen for different combinations of bitumen and aggregate types. Title: Understanding mechanical characterization of bitumen stabilized material Brief Description : Bitumen stabilized material is neither a bound material nor an unbound material - its properties lie somewhere in between. Test protocol needs to be developed for characterization of such material and modelling needs to be developed to predict its response. This will in turn help the engineers to build better roads with such materials.

Title: Studying influence of size and shape of aggregate particles on mechanical response of bituminous mixes Brief Description : Aggregates of different shapes, sizes, and their size distribution affect the performance of the bituminous mix. There is a need to develop a comprehensive theoretical model which can be used to predict the response of bituminous mix for given shape, size and distribution of aggregates. The results can be validated through laboratory and field studies. Title: Developing reliability based specifications for improved performance of bituminous mixes Brief Description : A number of strength and volumetric parameters are used for mix design of bituminous mixes. Acceptability of mix design requires satisfying certain specification limits of these parameters. However, these parameters may show significant variability in laboratory as well as in the field. Thus, there is a need to develop statistical (that is, reliability based) specifications for mix design of bituminous mix. Such specification can be implemented in the process of laboratory mix design and quality control during and after construction so as to achieve improved performance. Title: Developing test protocols for characterization of internal structure of bituminous mixes Brief Description : The arrangement between the constituents of bituminous mix affects the engineering property of the mix. There is a need to understand how the internal structure affects the response of bituminous mix. Such a study will eventually enable us to develop improved bituminous mixes. Title: Developing guidelines for optimal dosage of reclaimed asphalt pavement (RAP) materials for desired performance Brief Description : Varied quantity of reclaimed asphalt pavement (RAP) material is used in the recycled asphalt mix. The codes/ guidelines stipulate various permissible upper limits of RAP that can be used in a mix. Suitable technology needs to be developed for large scale usage of RAP in bituminous pavement. Appropriate test protocol and mix design approach need to be developed for maximum utilization of RAP in bituminous mixes. Title: Evaluating bituminous mixes using non-destructive tests Brief Description : Although number of approaches have been tried for non-destructive evaluation of bituminous mixes (for example, electromagnetic, electrical resistivity, nuclear, stress wave based etc.) the reliability of such measurement techniques for non-destructive evaluation of bituminous mixes need to be explored further. Elastic modulus, Poison's ratio, volumetric composition, rheological parameters, thermal conductivity, density etc are the parameters of interest. Title: Studying endurance limits of perpetual pavements Brief Description : Bituminous pavement designed for strain below the endurance limit of asphalt material can in principle have infinite fatigue life (known as perpetual pavement). Given the complex nature of bituminous material, it is a challenging task to estimate the endurance limit of bituminous material experimentally as well as theoretically. Title: Characterizing marginal materials for road construction Brief Description : Given the increased scarcity of natural resources, research effort is needed to explore usage of locally available marginal aggregates in road construction. Use of marginal materials stabilized with cement (or other cementing material) needs to be examined

as possible material (for constructing pavement layer) in concrete and bituminous pavements. Durability and long term strength aspects need to be studied for these materials. Title: Developing of test protocols for stabilized pavement materials Brief Description : Suitability and long term performance of stabilized materials is presently investigated based on simple empirical test methods. Selection of the required test methods are often agency specific which may often translate to poor performance or failure of these engineered materials. No standard test protocols to characterize the properties of these engineered materials are presently available. A standard test protocol to evaluate the properties of these materials needs to be developed to ensure satisfactory long term performance of these materials. Title: Characterizing industrial waste and construction and demolition (C&D) waste for pavement construction Brief Description : Country is presently facing the issue of disposal of industrial and construction and demolition (C&D) waste materials. An economically viable option for utilization/ disposal of these materials is to incorporate these as alternative construction material in pavement applications. Achieving this objective will require characterizing the material properties of these waste materials and modifying their properties so as to meet the pavement structural quality requirements. There may be a need to develop new test methods for evaluation of such materials. Title: Developing of mechanistic empirical method of (flexible/composite) pavement design Brief Description : Rutting models have to be developed for bituminous mixes, aggregate base and sub-layers and soils to estimate their individual contribution to rutting in a flexible pavement structure. Fatigue models for bituminous and cementitious layers also are to be developed. These models will be used in the mechanistic-empirical frame-work to develop reliable and economical pavement design in India. Title: Analysing damage due to spectrum of axle loads and effects of increased tyre pressure on performance of pavements Brief Description : Laboratory studies under compound loading, field observation on pavement performance are to be carried out to understand the mechanism of cumulative damage for bituminous mixes, cementitious mixes and cement concrete due to the effect of a given spectrum axle loads and tyre pressure. Title: Analytical and experimental investigations of top down cracking in bituminous pavements Brief Description : Top down cracking is a common phenomenon observed on bituminous roads. Its mechanism has not been understood clearly. Further research is needed for analytical evaluation and experimental validation of the phenomenon of top down cracking. Title: Designing sustainable pavements Brief Description : Sustainable pavements should be environment friendly with least damage to the environment and materials which can be reused again and again. The proposed study would explore possible application of various alternative technologies towards building sustainable pavement structure.

Title: Analysing bonded and un-bonded concrete pavements with and without tied shoulders Brief Description : The dry lean concrete (DLC) used as sub-base of concrete pavement is typically assumed as a support layer to the concrete pavement. A more realistic analysis is needed for both concrete slab as well as DLC as two plates resting on Winkler / Pasternak foundation for stress analysis. This improved analysis will be used for design of concrete pavements. Title: Developing intelligent compaction standards for improved performance of pavements Brief Description : Determination of density of compacted road material is an important exercise. There is a need to develop technologies for instant evaluation of density by sensors mounted on rollers so that the operator can visualize the amount of compaction achieved in different zones and can apply additional compaction wherever needed. Such an approach can be used for intelligent compaction of pavement being constructed. Title: Investigating crack propagation due to traffic on partially cured cementitious pavement layers Brief Description : Cracking in cemented pavement layers is a function of strength, environmental conditions and the super-imposed loading patterns. Superimposed load on partially cured cemented layers has a strong bearing on the crack formation and, therefore, the overall performance of these sections. This needs to be studied theoretically as well as experimentally. Title: Studying sub-surface drainage characteristics on performance of pavements Brief Description : To improve the performance of a pavement structure, a good sub-surface drainage system is needed which should have adequate permeability to take away the moisture from the pavement structure in a short time. Various studies on sub-surface drainage measures such as application of uniform sized aggregates, geo-composite layers, natural geo- textile layers etc are to be studied. Title: Analysing, designing and experimentally validating panelled concrete pavements Brief Description : Panelled concrete pavement is thinner and smaller in size than the conventional concrete pavements. The stresses are assumed to be lower, because due to small size, weight of the entire axle does not fall on the same panel. Its use as pavement for major highways and other roads are to be examined through rigorous analysis. Title: Studying shrinkage crack spacing for stabilised and concrete pavement layers Brief Description : Concrete undergoes natural shrinkage during the progression of hydration process. The shrinkage behaviour depends on various environmental parameters the pavement is exposed to. Provision of ad hoc spacing of contraction joints may lead to uncontrolled cracking of the concrete pavement. There is a need to understand the physical process of concrete shrinkage and subsequently develop models which can be used for design of shrinkage crack (contraction joint) spacing. Title: Developing specifications for bituminous layers in low temperature regions Brief Description : Hot mix bituminous material requires special attention for construction of roads in low temperature areas. Therefore, there is need to develop bituminous materials for paving applications in these areas and to develop suitable criteria for mix design.

Title: Determining recyclability of modified bituminous layers Brief Description : Crumb rubber modified binder (CRMB) and polymer modified binder (PMB) mixes have high strength and long life. While the top layer gets oxidised due to solar radiation and exposure to air, it becomes friable, crushable and can therefore be reused as recycled material. The modified mix in the lower layer however needs to be examined for its recyclability, because it may not get oxidised sufficiently so that it can be crushed and reused. Thus there is a need to study recyclability of different mixes and binders. Title: Developing decision support system on choice of recycling technique Brief Description : Recycling and reuse of preplaced pavement sections is an economical and environment-friendly alternative to limit the wastage of precious natural resources. Recycling option to be used for a particular section may vary depending on the properties of the existing section as well as on the target properties of the recycled material. Research efforts should focus on developing systematic approach to decide amongst the recycling options to be used in a given pavement section. Title: Developing high friction and quiet pavement surfacing Brief Description : Pavement surfacing plays an integral role in deciding the ride quality along the pavement sections. Emergence of high speed pavement facilities have resulted in noise control as an important consideration as a part of pavement construction. Effort needs to be made towards the designing pavement surfacing which can maintain lower noise level without compromising with the skid resistance requirement of the pavement surface. Title: Characterizing geo-synthetics for use in pavement construction Brief Description : Even though the use of geo-synthetics is known to improve pavement performance, the relevant properties and the underlying mechanism that contribute to the improvement are still unknown. The proposed research should focus on evaluating the effectiveness of current test methods used in characterization of geo-synthetic materials and on identifying pertinent parameters that defines the material behaviour. The knowledge gained can be incorporated to the current mechanistic-empirical design and analysis procedures. Title: Studying rapid construction techniques – pre-cast pavements Brief Description : Economic feasibility of a pavement project often depends on the time taken to complete the construction activities. Research should focus on development of innovative techniques/ technologies that can help shortening the construction window. Use of pre-cast pavement sections is one of such techniques. The analysis, design and construction methodologies for precast pavement need to be researched further. Title: Studying better surfacing for low volume roads Brief Description : Studies are to be done to examine low cost bituminous surfacing for low volume roads to alleviate dust nuisance. Use of bitumen emulsion and any other appropriate technology are to be examined/ developed. Title: Studying urban heat island effect Brief Description : The pavement surfaces can absorb heat during the day time which can contribute to a higher average day time temperature in urban areas compared to rural areas. This is known as urban heat island effect, which is an environmentally undesirable situation.

The research should therefore be directed towards developing appropriate design of road surface and geometrics, so that heat island effect can be reduced. Title: Modelling of temperature distribution in bituminous and concrete pavements under different climatic conditions Brief Description : Stress analysis of concrete and bituminous pavements requires information about variation of temperature with depth. A climatic model data is to be developed from the values of latitude, longitude, solar radiation, cloud cover, wind velocity, rainfall and thermal properties of road materials and surrounding. Concrete, bituminous mix, aggregate and soil have different thermal properties. These properties (as an input to the model) have to be evaluated in laboratory. The models have to be validated from field data from different part of the country. Title: Developing in-situ structural monitoring systems Brief Description : It is important to know the structural health of a freshly constructed pavement or at an interim period during the service life of pavement. Layer stiffness modulus, layer thicknesses, density, interlayer bonding, local anomaly etc are the parameters of interest. Various non-destructive techniques are used for structural health assessment of pavement. However, accuracy, speed, precision, robustness etc are some of the issues involved in the evaluation process, which requires further research attention. Title: Developing appropriate technologies for performance evaluation of pavements Brief Description : The performance of pavement is typically evaluated through the visible distresses (cracking, rutting, depression, ravelling, corrugation, shoulder drop-off etc). The skid resistance, and roughness, are some of the functional properties measured on pavement surface. Although various equipment are used for performance and functional evaluation of pavement structure, accuracy and speed, calibration, cost, time, bias in measurement etc are some of the issues involved. There is a need to develop equipment and approach for comprehensive performance evaluation of pavement structure. Title: Developing decision support system for road asset management Brief Description : Preservation and management of pavements are critical considerations for ensuring the long term service of pavement sections. Decision making on techniques to be used and management strategies are often based on empirical data arrived from studies conducted abroad which in most cases are not applicable to Indian conditions. Research should focus on development of a new decision support system based on data collected on Indian roads. Title: Identifying optimal timing for maintenance of highway pavements Brief Description : Preservation, maintenance and rehabilitation strategies contribute towards extending the service life of pavement. Selection of proper maintenance strategies and implementation schedule are critical in maximizing the utilization of existing materials and minimization of cost of maintenance ensuring long term service life of pavement sections. There is a need to develop suitable scheme to decide the optimal maintenance timing and the corresponding maintenance required.