Charisma Choudhury | Bangladesh University of Engineering & Technology (original) (raw)

Uploads

Papers by Charisma Choudhury

… and Traffic Theory …, 2007

Abstract: This paper demonstrates a methodology to model state dependency in lane changing behavi... more Abstract: This paper demonstrates a methodology to model state dependency in lane changing behavior by applying it to model the merging behavior of drivers on a congested freeway. The model has explicit normal, courtesy and forced merging components sequenced in a single detection framework. The decision to initiate a merge and the acceptance of gaps to complete the merge are affected by the decision state of the driver as well as neighborhood variables and driver characteristics (agent effect). The model ...

Driving is a complex task that includes a series of interdependent decisions. In many situations,... more Driving is a complex task that includes a series of interdependent decisions. In many situations, these decisions are based on a specific plan. The plan is however unobserved or latent and only the manifestations of the plan through actions are observed. Examples include selection of a target lane before execution of the lane change, choice of a merging tactic before execution of the merge. Change in circumstances (e.g. reaction of the neighboring drivers, delay in execution) can lead to updates to the initially chosen plan. These latent plans are ignored in the state-of-the-art driving behavior models. Use of these myopic models in the traffic simulators often lead to unrealistic traffic flow characteristics and incorrect representation of congestion.

86th Annual Meeting of …, Jan 1, 2007

… Record: Journal of the …, Jan 1, 2005

The lane-changing model is an important component of microscopic traffic simulation tools. With t... more The lane-changing model is an important component of microscopic traffic simulation tools. With the increasing popularity of these tools, a number of lane-changing models have been proposed and implemented in various simulators in recent years. Most of these models are based on the assumption that drivers evaluate the current and adjacent lanes and choose a direction of change (or not to change) based on the utilities of these lanes only. The lane choice set is therefore dictated by the current position of the vehicle, and in multi-lane facilities would be restricted to a subset of the available lanes. Thus, existing models lack an explicit tactical choice of a target lane and therefore cannot explain a sequence of lane changes from the current lane to this lane.

Driving behavior is significantly affected by the presence of exclusive lanes. Particularly, unli... more Driving behavior is significantly affected by the presence of exclusive lanes. Particularly, unlimited access to exclusive lanes result significant amount of special type of lane-changing actions. The objective of this thesis is to develop an improved lanechanging model that has a generalized structure and is flexible enough to capture the lane-changing behavior in all situations including the presence of unlimited access

… Research Board 87th …, Jan 1, 2008

Abstract: Lane-changing models are important components of microscopic traffic simulation tools. ... more Abstract: Lane-changing models are important components of microscopic traffic simulation tools. State-of-the-art models adopt a two-level decision framework comprising of lane selection followed by gap acceptance to explain lane changing behavior. However, lane changes have been modeled as an instantaneous process that is initiated and completed at the same time step following gap acceptance. But in reality, lane-changing is a continuous process with an average duration of 3-7 seconds, as reported in past works. This practical ...

Proceedings of the …, Jan 1, 2006

This paper summarizes a series of advances in lane changing models, which aim to provide fuller a... more This paper summarizes a series of advances in lane changing models, which aim to provide fuller and more integrated representation of drivers' behavior. These advances include integration of mandatory and discretionary lane changes in a single framework, inclusion of explicit target lane choice in the decision process and incorporation of various types of lane changing mechanisms, such as cooperative lane changing and forced merging. In the specifications of these models, heterogeneity in the driver population and correlations among the various decisions a single driver makes across choice dimensions and time are addressed. These model enhancements were implemented in the open source microscopic traffic simulator of MITSIMLab. Their impact is demonstrated in validation case studies that compare their performance to existing models.

Triennial Symposium on …, Jan 1, 2007

The gap between discrete choice models and behavioral theory has spurred various developments tha... more The gap between discrete choice models and behavioral theory has spurred various developments that attempted to enrich the behavioral realism of discrete choice models by explicitly modeling one or more components of the "black box" of decision-making (e.g. accounting for attitudes and perceptions) or employing more flexible error structures in the specification of the utility function (see for example . The most general framework that has been proposed to date has been the Hybrid Choice Model (HCM) which integrates latent variable and latent class models with discrete choice methods to model the influence of latent variables and classes on the choice process. Latent variable models capture the formation and measurement of latent psychological factors, such as attitudes and perceptions, which explain unobserved individual heterogeneity. Latent class models also capture unobserved heterogeneity by modeling latent segments of the population that could differ in their choice sets or decision protocols for example.

Transportation Research Record …, Jan 1, 2008

In this paper, we present a lane choice model for urban arterial intersections. This replaces the... more In this paper, we present a lane choice model for urban arterial intersections. This replaces the rulebased heuristics to assign vehicles in their subsequent lanes used in state-of-the-art microscopic traffic simulators. The lane choice at intersections is modeled as a two step process: target lane choice and immediate lane selection based on the selected target lane. The target lane is the lane the driver perceives as the best to be in taking a wide range of factors and goals into account. These include path-plan considerations and lane-specific attributes and can vary with the planning capability and aggressiveness of the driver. However, maneuver to the target lane may not be possible immediately. The observed trajectories only consist of the immediate lane choices of the drivers. The choice of immediate lane is conditional on the target lane selection and affected by maneuverability considerations and aggressiveness of the driver. The parameters of the target lane and immediate lane choice models are jointly estimated with detailed vehicle trajectories. The heterogeneities of the driver population, both in terms of planning capability and aggressiveness, are explicitly taken into account in the model formulation. The estimated model is compared with a single level intersection lane choice model to demonstrate the improvements in the goodness-of-fit. The improvements are further strengthened by validation studies within the microscopic traffic simulator MITSIMLab where the simulation results using the proposed model yield better matches with observed data compared to the rule-based models. TRB 2008 Annual Meeting CD-ROM Paper revised from original submittal.

… on Travel Behavior …, Jan 1, 2009

With the increased popularity of stated preference (SP) surveys for evaluating user preferences, ... more With the increased popularity of stated preference (SP) surveys for evaluating user preferences, there has been significant research on survey design techniques and associated issues. Most of these researches have focused on the efficiency and balance of the designs as well as consistency of responses under large and complex choice scenarios (DeShazo and Farmo 2002, Louvierre et al. 2008). However, though there has been research on approaches to deal with large choice sets in consumer choice settings (e.g. telecom features (Ben-Akiva and Gershenfeld 1998) magazine subscription (McAlister 1979), entertainment services (Venkatesh and Mahajan 1993), auto-ownership (Hanson and Martin 1990) etc.), to our knowledge, there has not been significant research on practical approaches that can be used to deal with cases in the travel mode choice context where presenting large number of alternatives in a single survey is essential given the particular scenario of application and resource limitations.

… of Traffic Simulation, Jan 1, 2010

MITSIMLab (MIcroscopic Trafic SIMulation Laboratory) is a microscopic trafﬁc simulation model tha... more MITSIMLab (MIcroscopic Trafic SIMulation Laboratory) is a microscopic trafﬁc simulation model that evaluates the impacts of alternative trafﬁc management system designs, traveler information systems, public transport operations, and various ITS strategies at the operational level and assists in their subsequent reﬁnement. MITSIMLab can evaluate systems such as advanced trafﬁc management systems (ATMS) and route guidance systems.