Papers by Aleksandar Stevanovic
CivilEng
Transportation agencies periodically conduct signal retiming (i.e., optimization) to ensure effic... more Transportation agencies periodically conduct signal retiming (i.e., optimization) to ensure efficient signal operations. Previous studies introduced the notion of the “resonant cycle length” (RCL), which is based on the premise that a good progression of traffic on the corridor mainline for various volume fluctuations can be achieved with an appropriate value of cycle lengths, where all other signal timing parameters (splits, offsets and phase sequences) remain unaltered. Several follow-up studies brought many inconsistencies in the previously introduced concept. For instance, authors would investigate the existence of the RCL by evaluating the performance of signal timing plans for not only coordinated movements (side streets and coordinated movements together), but would optimize all signal timing parameters (not only cycle lengths) while investigating. This study sheds light on the RCL concept and highlights the importance of all signal timing parameters for signal performance. I...
PROMET - Traffic&Transportation, 2016
Over the last three decades numerous research efforts have been conducted worldwide to determine ... more Over the last three decades numerous research efforts have been conducted worldwide to determine the relationship between traffic accidents and traffic and road characteristics. So far, the mentioned studies have not been carried out in Serbia and in the region. This paper represents one of the first attempts to develop accident prediction models in Serbia. The paper provides a comprehensive literature review, describes procedures for collection and analysis of the traffic accident data, as well as the methodology used to develop the accident prediction models. The paper presents models obtained by both univariate and multivariate regression analyses. The obtained results are compared to the results of other studies and comparisons are discussed. Finally, the paper presents conclusions and important points for future research. The results of this research can find theoretical as well as practical application.
The contents of this report reflect the views of the authors, who are responsible for the facts a... more The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the information presented. This document is disseminated under the sponsorship of the
Energies
Optimizing traffic signals to improve traffic progression relies on minimizing mobility performan... more Optimizing traffic signals to improve traffic progression relies on minimizing mobility performance measures (e.g., delays and stops). However, delay and stop minimizations do not necessarily lead to minimal sustainability measures (e.g., fuel consumption and emissions). For that reason, researchers have focused, for decades, on integrating traffic models, signal optimization models, and fuel consumption and emissions models to minimize sustainability metrics while keeping acceptable levels of mobility metrics. Therefore, this paper reviews, classifies, and analyzes studies found in the literature regarding optimizing sustainable traffic signals. This paper provides researchers with a good starting point to further develop solutions which can address sustainable traffic control. To achieve that, this study details the most notable sustainable signal timing optimization studies from six perspectives: traffic models, fuel consumption and emissions models, optimization methods, objecti...
Future Transportation
Improperly scheduled signal timing plans are one of the main reasons for reduced efficiency of tr... more Improperly scheduled signal timing plans are one of the main reasons for reduced efficiency of traffic signals at coordinated urban arterials. Recently, most urban arterial roads are equipped with intelligent transportation systems devices capable of reporting the collected data on high temporal and spatial resolution, which gives us the opportunity to overcome traditional signal timing planning flaws. Previous studies have proposed methods for scheduling signal timing plans based on small quantities of data combined with various optimization approaches that ultimately require domain expert intervention to fine-tune proposed solutions. Consequently, the signal timing plans scheduling problem is still being addressed without a comprehensive approach. In this study, we propose a novel data-driven procedure based on visual analytics principles to identify the dominant traffic profiles and appropriate scheduling of signal timing plans. The medium-resolution volume data collected over a ...
Proceedings of 2nd the International Conference on Civil Engineering Fundamentals and Applications (ICCEFA'21), 2021
Vehicular delay represents one of the fundamental traffic signal performance measures. In the pas... more Vehicular delay represents one of the fundamental traffic signal performance measures. In the past, number of delay models were developed mainly to estimate delays for exclusive phases (movements). In cases of left-turn movements that are served in protected/ permissive mode, there are very few models that can be used to estimate delays. Previously developed models for left/turn protected/permissive mode are based on a number of assumptions related to vehicular arrival/departure patterns. Thus, when used to estimate delays in a real-time manner, such models are prone to erroneous estimates. In this study, to overcome the limitations of current models, authors proposed a novel delay model for protected/permitted left turn operations based on Multigene Genetic Programming (MGGP) technique. Relevant data were collected on a cycle-by-cycle basis using the microsimulation model of real-world arterial. Using the MGGP, a novel delay model and its analytical formulation were proposed and co...
Transportation Research Record: Journal of the Transportation Research Board, 2020
In a fully connected traffic environment with automated vehicles, new traffic control strategies ... more In a fully connected traffic environment with automated vehicles, new traffic control strategies could replace traditional traffic signals at intersections. In recent years, several studies about reservation-based intersection control strategies have been published, and a significant increase in capacity was shown. In the strategies presented so far, other road users usually play a minor role or are not considered at all. However, many use cases of automated driving occur in urban environments, where pedestrians and bicyclists play a major role. In this paper, a novel strategy for integrating pedestrians into automated intersection management is introduced and compared with a fully actuated traffic (AT) signal control. The presented control consists of a first-come, first-served strategy for vehicles in combination with an on-demand traffic signal for pedestrians. The proposed intersection control is explained, implemented, and tested on a four-leg intersection with several lanes co...
PDFTech ReportBDV27-977-06Event data recordersSignalized intersectionsTraffic signal controllersD... more PDFTech ReportBDV27-977-06Event data recordersSignalized intersectionsTraffic signal controllersData loggingFloridaFlorida. Dept. of TransportationStevanovic, AleksandarFlorida. Dept. of TransportationUS Transportation CollectionNew traffic signal controllers, which have advanced data collection abilities, offer better information about the response of traffic signal timings to traffic flows. However, traffic engineers need more than raw data. The controllers must be set up to record meaningful events in order to establish performance measures. The Florida Department of Transportation (FDOT) sought analysis and recommendations regarding the capability of these new controllers and their potential for use with automatic signal performance measurement system software.Research ObjectivesFlorida Atlantic University researchers investigated the capabilities and features of six different signal controllers to determine the minimum standards that these controllers must meet to be approved for use in Florida. The overall performance of the controllers was also evaluated
This paper evaluates impact of various I-15 reconstruction closure scenarios on the travelers in ... more This paper evaluates impact of various I-15 reconstruction closure scenarios on the travelers in Ogden area. The purpose of the research was to investigate impact of the scenarios and facilitate decision about future maintenance of traffic during the reconstruction. The original Wasatch Front Regional Council (WFRC) transportation planning model was converted from the TP+ software to the VISUM software. The VISUM model of the whole WFRC area was then calibrated and validated. Coefficient of determination between modeled and observed traffic volumes was 0.78. The model was then reduced, by partial network generation process in VISIM, to the Ogden area. Another set of calibration and validation was performed. The coefficient of determination has improved to 0.88. Twenty one reconstruction closure scenarios were developed in consultation with Utah Department of Transportation (UDOT) project managers. Traffic assignments were executed for each scenario for five diurnal periods. Measures...
International Journal of Transportation Science and Technology, 2021
Transportation Research Record: Journal of the Transportation Research Board, 2021
The Performance Index (PI), a widely used composite measure of vehicular stops and delays, is one... more The Performance Index (PI), a widely used composite measure of vehicular stops and delays, is one of the most popular traffic signal performance measures. Over the decades it has been used to achieve a proper balance between delays and stops. Its key component, the “stop penalty,” has been used to minimize excess fuel consumption from unnecessary stops caused by traffic control operations. In signal optimization practice this stop penalty, also known as the K factor, has been set as an invariable parameter with a relatively low value ∼10 to 20. This paper questions this widely accepted practice. It first explains the origins and meaning of the PI and the significance of the K factor. Then, it lists various studies, discusses their inconsistencies, and introduces a new Fuel Consumption Intersection Control PI (FCIC-PI). The paper also presents findings from field data collection and compares them with the other studies, including some simulation results. Outcomes of these various fin...
Journal of Transportation Technologies, 2018
On-road Vehicular traffic congestion has detrimental effect on three lifelines: Economy, Producti... more On-road Vehicular traffic congestion has detrimental effect on three lifelines: Economy, Productivity and Pollution (EPP). With ever increasing population of vehicles on road, traffic congestion is a major challenge to the economy, productivity and pollution, notwithstanding continuous developments in alternative fuels, alternative sources of energy. The research develops accurate and precise model in real time which computes congestion detection, dynamic signaling algorithm to evenly distribute vehicle densities while ensuring avoidance of starvation and deadlock situation. The model incorporates road segment length and breadth, quality and achievable average speed to compute road capacity. Vehicles installed with GPS enabled devices provide their location, which enables computing road occupancy. Road occupancy is evaluated based on number of vehicles as well as area occupied by vehicles. Ratio of road occupancy and road capacity provides congestion index important to compute signal phases. The algorithm ensures every direction is serviced once during a signaling cycle ensuring no starvation. Secondly, the definition of minimum and maximum signal timings ensures against dead lock situation. A simulator is developed to validate the proposition and proves it can ease congestion by more than 50% which is better than any of the contemporary approaches offering 15% improvement. In case of higher congestion index, alternate routes are suggested based on evaluation of traffic density graphs for shortest route or knowledge database. The algorithm to compute shortest route is optimized drastically, reducing computation cost to 3 2N * vis-à-vis computation cost of N 2 by classical algorithms. The proposal brings down the cost of implementation per traffic junction from USD 30,000 to USD 2000.
SpringerBriefs in Computer Science, 2016
The rapid growth of urban population and number of private cars in this modern era, results in in... more The rapid growth of urban population and number of private cars in this modern era, results in increasingly urgent transportation problem in cities throughout the world. Road traffic congestion is an omnipresent problem, which leads to delays, time loss, human stress, energy consumption, environmental pollution etc. In order to decrease traffic congestion, there is a need for simulating and optimizing traffic control and improving traffic management. There are different ways for traffic congestion monitoring and analysis such as using video monitoring and surveillance systems, or static and dynamic sensors which allow traffic management in real time. There are also other methods using non real time analysis where traffic congestion can be extracted from historical patterns of traffic congestion. The historical patterns can be gained from the stored travel time and speed data. The goal of enhancing driver convenience is achieved by providing applications based on road traffic condition that mainly identifies congestion status. This section presents a web application which uses live traffic congestion data from Google Maps™ traffic layer for real time congestion calculation. A technique utilized for estimating the level of congestion is image processing. The main objective is to provide an automated and yet interactive visualization tool for congestion analysis in real time. The aim is reducing the traffic congestion on roads which will lead to decrease in the number of accidents. The application can provide important data which can help road traffic management. Thus, it is mainly dedicated to traffic managers, operators and analysts. Nevertheless, it can be implemented also by road users. Unlike most sensor based applications, it makes quantified congestion data available even in regions with limited traffic data information.
SpringerBriefs in Computer Science, 2016
the material is concerned, specifi cally the rights of translation, reprinting, reuse of illustra... more the material is concerned, specifi cally the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfi lms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specifi c statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.
Na nasl. str.: A thesis submitted to the faculty of The University of Utah in partial fulfillment... more Na nasl. str.: A thesis submitted to the faculty of The University of Utah in partial fulfillment of the requirements for the degree of Master of Science in Civil Engineering. - Umnozeno za odbranu. - University of Utah, Department of Civil and Environmental Engineering, odbranjeno 12.12.2002. - Bibliografija: listovi 146-148. - Abstract.
This paper investigates the aging of pre-timed traffic control through the use of Synchro and Sim... more This paper investigates the aging of pre-timed traffic control through the use of Synchro and SimTraffic. The first section of the paper presents the concept of aging of signal timing plans and the second part estimates the benefits of optimized timing plans in Synchro in the micro simulation environment of SimTraffic. The theoretical nine-node grid network is used as a test bed to model 21 scenarios of deterministic and 100 scenarios of stochastic traffic demand and distribution changes in link flows. The research does not prove the existence of unique aging measures which could correlate any change in link traffic flows with the benefits of signal retiming. The results show that for networks with unchanged traffic distributions, there is a benefit of up to 3% for up to 5% of uniform growth in traffic demand. When stochastic variations of traffic demand and distribution are introduced, the benefits rise to an average of 35%. The measured benefits from the other field retiming projects confirm that estimations from this study are within the same range.
Abstract: Interstate 15 in Utah's Salt Lake City metropolitan region has 38 miles of Hig... more Abstract: Interstate 15 in Utah's Salt Lake City metropolitan region has 38 miles of High-Occupancy Vehicle (HOV) lanes. In September 2006, the HOV lanes became High-Occupancy/Toll (HOT) lanes. For a monthly fee of $50, Single-Occupant Vehicle (SOV) ...
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Papers by Aleksandar Stevanovic