Alexandra Kondyli | University of Kansas (original) (raw)

Papers by Alexandra Kondyli

Although significant advances have been done with respect to vehicle technology and roadway const... more Although significant advances have been done with respect to vehicle technology and roadway construction, driver behaviour remains the number one contributing factor of traffic crashes worldwide. Studies show that one of the major causes of crashes is driver inattention. Driver inattention may occur when drivers are involved with secondary activities (e.g., texting, talking on the phone, or eating), and when they fail to follow the cues of the surrounding environment while driving. The latter is particularly important when drivers are negotiating maneuvres and are required to interact with other vehicles as in the case of changing lanes or merging onto the freeway. The main objective of this research is to investigate the relationship between driver behavior and safety, by looking at the actual body movements and posture, as well as the eye fixation of the drivers when they are performing lane changing and merging maneuvers under different traffic conditions. To accomplish this obje...

IEEE Intelligent Transportation Systems Magazine, 2015

A significant amount of research has been involved with the development of advanced driverassista... more A significant amount of research has been involved with the development of advanced driverassistance systems. Such systems typically include radars, laser or video sensors that detect the vehicle trajectory and warn for an imminent lane departure, or sense the front vehicle's speed and apply the brakes of the following vehicle to maintain safe distance headways (i.e., collision avoidance system). However, most of these systems rely on the subject vehicle and surrounding vehicles' position and do not explicitly consider the driver's actions during the driving task. In addition, safety research has focused on eye tracking as a means of capturing driver's attention, fatigue, or drowsiness; however, the body posture has not been investigated in depth. This paper presents a novel approach for studying the actual movements of drivers inside the vehicle, when performing specific maneuver types such as lane changing and merging. A pilot study was conducted along a freeway and arterial segment, where the 3D shapes of selected participants were constructed with the use of Microsoft Kinect range camera while merging and changing lanes. A 7-point human skeletal model was fit to the captured range data (depth frame sequences) using the proposed framework. The analysis of the captured 3D data showed that there are important differences between participants when performing similar driving maneuvers. The preliminary results of this pilot research set the basis for implementing the proposed methodological framework for conducting full-scale experiments with a variety of participants, and exploring differences due to driver behavior attributes, such as age, gender and driving experience.

Transportation Research Record, Nov 30, 2022

2018 21st International Conference on Intelligent Transportation Systems (ITSC), 2018

Freeway merges are one of the most significant sources of traffic congestion. This study proposes... more Freeway merges are one of the most significant sources of traffic congestion. This study proposes a dynamic signal control algorithm for an integrated ramp and mainline metering control strategy to improve freeway operation and reduce environmental impacts at freeway merging areas. The presented algorithm uses real-time traffic sensor information to predict the future status of downstream queue and dynamically control the signal. For safety reasons, the mainline signal control is activated only when a significant speed drop is detected at all lanes of the mainline and the traffic has been already almost stopped. The results of the simulation analyses on a real-world calibrated network show a maximum of 15.7% improvement in average speed, 20.9% reduction in average delay, and 13.7% decrease in CO emission.

Federal Highway Administration2020PDFTech ReportHale, David K.Ma, JiaqiChiasi, AmirVolet, PascalC... more Federal Highway Administration2020PDFTech ReportHale, David K.Ma, JiaqiChiasi, AmirVolet, PascalCesme, BurakKondyli, AlexandraSchroeder, Bastian J.Sethi, SonikaTorres, LauraBelisle, FrancoisUnited States. Federal Highway AdministrationLeidos, Inc.Bared, Joe G.United States. Federal Highway AdministrationUnited StatesMerging controlManaged lanesMainline meteringRamp meteringInterchanges and intersectionsBottlenecksSplit mergeManaged lanesMainline meteringCoordinated ramp meteringSpeed optimizationFreeway mergeFHWA-HRT-20-008DFTH6116D00030Bared, JoeThe Contracting Officer's Representative was Joe Bared (HRDO-20).Alternative intersections and interchanges brought major benefits to the United States during the 2008\u20132018 time period. Given the positive impacts, it stands to reason that similar breakthroughs might be possible at freeway merge and diverge locations. This report describes the outcomes of a project that examined this possibility. The primary tool of evaluation was sensitivity analysis via microscopic traffic simulation, also known as microsimulation. The split merge design, and the positioning of managed lanes on the right side of the freeway, are two unrelated designs that showed excellent promise (in terms of benefit\u2014cost ratio). Coordinated ramp metering did not show significant additional benefits beyond conventional asservissement lin\u2019eaire d'entr\u2019ee autorouti\u2018ere, also known as ALINEA, metering. Speed optimization showed excellent benefits but only during narrow ranges of traffic congestion. Mainline metering also showed reasonably good benefits but could be challenging to implement. It is conceivable that speed optimization and mainline metering could produce more favorable benefit\u2014cost ratios if they could be implemented via connected and automated vehicle (CAV) technologies. However, the split merge and right-side managed lane designs produced excellent benefits without the need for CAV technologies.96

IET Intelligent Transport Systems, 2021

Traffic analysis procedures are becoming more robust over time. However, there is still significa... more Traffic analysis procedures are becoming more robust over time. However, there is still significant room for improvement both in practitioners' adoption of robust methods and in robustness of the methods themselves. One example of oversimplified practice involves peak hour or 30th highest hour analysis, which fails to capture the impacts of varying demands and operating conditions. To address this limitation, detailed reliability modelling procedures were developed for the Highway Capacity Manual (HCM), but these procedures bring challenging input data and calibration requirements. A new generation of datadriven tools is capable of real-time congestion identification, but their performance measures are only beginning to improve and evolve. Finally, comparing and ranking congested locations (i.e. bottlenecks) on the basis of experience and judgment lacks credibility unless backed by quantitative results. This study discusses the development of new and innovative performance measures for congestion measurement. A case study of ranking eight real-world bottlenecks based on the proposed measures and existing HCM measures produced new insights that could improve both approaches. Ideally, these new insights and methods would be accepted by agencies and/or commercial products for a new level of robustness in congestion measurement. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Transportation Research Part F: Traffic Psychology and Behaviour, 2021

Abstract Driver comprehension is a substantial component of situation awareness that involves the... more Abstract Driver comprehension is a substantial component of situation awareness that involves the ability of an individual to understand the significance of an object, traffic sign, or hazard while driving. An increase in crashes related to autonomous driving systems has raised a concern regarding the safety of other roadway users due to the diminishing accountability resulting from a general lack of understanding of the limitations or disregard of the safety protocols by users. To keep drivers vigilant when engaged in partial automated systems, a methodology to monitor real-time driver comprehension was proposed. A driving simulator study consisting of 90 participants, equally split between males and females, was executed to establish driver comprehension in six different variations of driving difficulty. Joint probability density functions were created by considering percent time spent gazing, answers to probe questions, and driving performance. Based on these density functions, five levels of comprehension were devised and assigned thresholds. Overall, as task difficulty increased, a non-linear deterioration in driving speed along with an increase in total gaze duration was observed before comprehension was attained. A two-step validation protocol was also proposed to ensure similar levels of comprehension to non-automated driving from the human driver, when engaged in early forms of automation. The proposed real-time driver comprehension monitoring constitutes a first step toward developing a methodology to reinstate the accountability of safety of other roadway users when engaged in driver-in-the-loop automation systems.

2019 ASEE Annual Conference & Exposition Proceedings

Dr. Kondyli has worked on research projects funded by Kansas DOT, Florida DOT, USDOT, and by the ... more Dr. Kondyli has worked on research projects funded by Kansas DOT, Florida DOT, USDOT, and by the National Cooperative Highway Research Program (NCHRP). She has authored and co-authored more than fifty publications, presentations and reports related to traffic operations, simulation, highway capacity, safety, and driver behavior. Dr. Kondyli is currently the Chair of the Freeways/Multilane Highways of the Highway Capacity and Quality of Service Committee (AHB40) of the Transportation Research Board. She also has consulting experience in the fields of traffic operations, geometric design and roadway safety. Dr. Kondyli received her Graduate Diploma in Rural and Surveying Engineering, (five year program) from

Transportation Research Record: Journal of the Transportation Research Board, 2020

This research aims to examine the effect of incidents with lane closures and adverse weather cond... more This research aims to examine the effect of incidents with lane closures and adverse weather conditions (medium to heavy rain intensity) on capacity and free-flow speed (FFS) of freeway segments. Data were collected from multiple freeway segments located in the Kansas City, U.S., metro area from 2014 to 2018. The capacity and FFS were measured for two-lane, three-lane, and four-lane freeways under four conditions: ( 1 ) base conditions, ( 2 ) adverse weather only, ( 3 ) incidents only, and ( 4 ) adverse-weather-and-incidents. Capacity adjustment factors (CAF), and speed adjustment factors (SAF) were established to identify the remaining capacity or the FFS reduction during an incident or adverse weather conditions. The findings indicated that medium to heavy rain resulted in a 5% reduction in FFS at three-lane sites which is consistent with the adjustment factors shown in the Highway Capacity Manual 6th edition (HCM6); however, rain was not found to have a significant impact on free...

Accident Analysis & Prevention, 2020

Driving is a complex task that consists of several physical (motor-related) and physiological (bi... more Driving is a complex task that consists of several physical (motor-related) and physiological (biological changes within the body) processes occurring simultaneously. The complexity of the task depends on several factors, but this research focuses on work zone configurations and their effect on driver performance and gaze behavior. The increase in work zone fatalities in the United States between 2015 and 2018 coupled with the limited literature of driver behavior in these complex environments requires a more comprehensive study. Given the nature of these crashes, typically lane departures, gaze behavior provided an additional physiological dimension to the present research. A framework that comprises of the interactions between driver characteristics, mental workload, and situation awareness, with longitudinal control, lateral control, and gaze behavior is proposed. Crash analysis and a simulator study with 90 participants were carried out to investigate the performance and gaze-based changes with respect to various work zone configurations. Distracted driving was also studied by including a secondary task. The results showed a significant interaction between the longitudinal control and the standard deviation of horizontal gaze position in predicting lateral control. Also, significant differences in lateral control and horizontal gaze variations were observed between genders. Female drivers showed lower lateral position deviations and lower horizontal gaze variability. This was a key finding given the inherently higher number of work zone crashes involving male drivers. Placing work zone barriers further away, by up to one meter from pavement edges, could significantly decrease mental workload and improve safety in work zones.

Transportation Letters, 2019

Past research acknowledged the impact of ramp vehicles on the occurrence of a breakdown event, bu... more Past research acknowledged the impact of ramp vehicles on the occurrence of a breakdown event, but little has been done to quantify the effect of the ramp vehicles on the resulting bottleneck capacity. The objective of this research is to explore the relationship between ramp flow and capacity and to recommend capacity values for merge bottleneck locations. To explore the relationship between ramp flow and capacity, a capacity model has been developed using linear regression. The Kansas City area freeway network was considered for the analysis. Multiple locations that experienced 'true breakdowns', i.e., breakdowns caused by merging operations and not due to downstream spillback, were selected for the analysis. Demand-derived variables such as ramp-tofreeway demand ratio and flow distribution were found to be statistically significant. The regression model was used to predict capacity values for different ramp and freeway demands. By observing the calculated capacity values it was concluded that capacity decreases as the ramp-to-freeway demand ratio increases.

Transportation Research Record: Journal of the Transportation Research Board, 2019

Unnecessary traffic delays and vehicle emissions have adverse effects on quality of life. To solv... more Unnecessary traffic delays and vehicle emissions have adverse effects on quality of life. To solve the traffic congestion problem in the U.S.A., mitigation or elimination of bottlenecks is a top priority. Agencies across the U.S.A. have deployed several congestion mitigation strategies, such as lane and shoulder width reduction, which aim to adding lanes without significantly altering the footprint of the freeway. A limited number of studies have evaluated the operational benefits of lane narrowing. Although the Highway Capacity Manual does account for lane and shoulder widths, the adjustments that it provides are outdated. The goal of this research was to develop analytical models, compatible with the Highway Capacity Manual methods, to account for lane and shoulder width narrowing, using field data from across the U.S.A. This paper presents a new free-flow speed regression model, which accounts for lane and shoulder widths, and capacity adjustment factors depending on the lane width.

Journal of Advanced Transportation, 2019

Ramp metering has been found to improve traffic conditions on the freeway mainline by breaking th... more Ramp metering has been found to improve traffic conditions on the freeway mainline by breaking the platoons of ramp vehicles minimizing turbulence at the merge locations. The majority of the ramp metering evaluation studies have examined traffic performance under specific demand conditions, whereas travel time reliability and variability aspects have not been adequately addressed. This paper focuses on evaluating two well-known ramp metering algorithms in terms of travel time reliability as well as other performance measures such as queue lengths, throughput, and congestion duration, looking at a wide range of traffic demands throughout a calendar year. The evaluation was done through simulating an 8-mile corridor in Kansas City, KS. The results showed localized improvements due to ramp metering at the northern section of the facility, in terms of travel time reliability, throughput, and congestion duration. It was also shown that ramp metering may cause a new (possibly “hidden”) bo...

Transportation Research Record: Journal of the Transportation Research Board, 2018

The capacity of a freeway segment is a critical factor for planning, design, and operational anal... more The capacity of a freeway segment is a critical factor for planning, design, and operational analysis of freeway facilities. This research aimed to perform a comparison among well-known freeway capacity estimation methods in order to investigate their application, as well as their advantages and disadvantages. Single estimate capacity methods such as the Van Aerde method, and breakdown probability methods, such as the product limit method (PLM), the Highway Capacity Manual (HCM) method, and the sustainable flow index (SFI) method, were applied at six merge bottleneck locations in the Kansas City area. The results from all methods were compared and the advantages and the disadvantages of each method were discussed. The HCM results showed a significant variability in the estimated breakdown probability function and the resulting capacities. The HCM method was also found to be sensitive to the breakdown probability ratios as a single breakdown observation can significantly shift the fi...

Journal of Transportation Safety & Security, 2018

Engineering and the Graduate Faculty of the University of Kansas in partial fulfillment of the re... more Engineering and the Graduate Faculty of the University of Kansas in partial fulfillment of the requirements for the degree of Master of Science in Civil Engineering.

Journal of Advanced Transportation, 2017

Operational performance optimization of signalized intersections is one of the most important tas... more Operational performance optimization of signalized intersections is one of the most important tasks for traffic engineers and researchers. To compensate for the limitations of practical implementation, simulation software packages have been widely used to evaluate different optimization strategies and thus to improve the efficiency of the intersections as well as the entire network. However, for the existing optimization studies on signalized intersections, the relationships among various optimization measures and the combination of strategies have not been fully investigated. In this paper, uniform design experimentation was introduced to combine different optimization measures into strategies and achieve the minimum time cost in model construction. VISSIM software package was then calibrated and used to evaluate various optimization strategies and identify the one with the best measurement of performance, namely, control delay at the signalized intersection. By taking a representa...

Transportation Research Record: Journal of the Transportation Research Board, 2016

The Highway Capacity Manual 2010 (HCM 2010) contains computational procedures for evaluating traf... more The Highway Capacity Manual 2010 (HCM 2010) contains computational procedures for evaluating traffic operational efficiency of urban street segments. These procedures have been implemented within several commercial software packages and are likely used by thousands of engineers and planners across the United States. The procedures for urban street capacity analysis contain no logic for handling right turns on red (RTORs) or for handling special cases of RTORs such as shielded and free right turns. A new proposed RTOR modeling framework is described for urban streets in the HCM 2010. When significant upstream RTOR flows exist, the proposed logic is designed to generate more realistic flow profiles. Three types of experimental results are presented: they demonstrate the improved modeling accuracy of the proposed logic. First, it is shown that macroscopic flow profile shapes are now more visually sensible because they now illustrate RTOR flows moving at the appropriate times. Second, m...

Journal of Transportation Engineering, Part A: Systems, 2017

AbstractThe highway capacity manual (HCM) is the publication used most often to estimate capacity... more AbstractThe highway capacity manual (HCM) is the publication used most often to estimate capacity. Field measurements in previous research have shown that the capacities at several freeway bottlene...

Transportation Letters, 2016

Travel time is an important performance measure used to assess traffic operational quality of var... more Travel time is an important performance measure used to assess traffic operational quality of various types of facilities. Previous efforts to estimate travel time have also compared model-estimated travel times to field-measured travel times using various sources of data. Given the variety and diversity of travel time measurement methods, it is important to evaluate the accuracy of the data obtained by each of them and to develop recommendations regarding their suitability in the validation of travel time estimation models. The research objective for this paper was to collect field data along several freeways and arterials and to evaluate the travel times obtained by STEWARD (Statewide Traffic Engineering Warehouse for Regionally Archived Data), INRIX, BlueTOAD (Bluetooth Traveltime Origination and Destination), and HERE. Benchmark data were collected with the use of an instrumented vehicle at five freeway segments and two arterial segments in Florida. The fieldmeasured travel times were statistically compared with the travel times provided through various methods. The results suggest that the HERE traffic data provide better freeway travel time estimates compared to the remaining methods. In oversaturated conditions, STEWARD, INRIX and BlueTOAD data seem to underestimate travel times, while HERE data were found to be more accurate. For undersaturated freeways, STEWARD, INRIX and BlueTOAD were found to perform better than HERE. At the arterial sites BlueTOAD and HERE travel time data were analyzed and the analysis suggests that none of the methods is accurate, possibly due to the small sample size.

Arterial roadways are designed to provide both accessibility and mobility to the users. Arterials... more Arterial roadways are designed to provide both accessibility and mobility to the users. Arterials play a very important role in the roadway system, due to the variety of their functions and their role in connecting various roadway facilities (freeway – arterial, arterial – arterial, arterial – collector – local street). The objective of this study is to develop analytical models that estimate arterial link travel time considering mid-block delays. Simulation was the primary tool used for model development. A limited amount of field data were collected for simulation model calibration in two-lane two-way and two-lane one-way arterial streets. An experimental design was constructed to expand the database. Regression analysis was applied for the development of the analytical models of mid-block delay. The results of the analysis yielded different equations for the mid-block delay depending on whether the arterial is operating under congested or uncongested conditions.