The purpose of this research is to develop methodologies for applying traffic flow theories to various ITS categories through the utilization of evolving surveillance technologies. This integration of theory, measurement and application has been overlooked since the advent of ITS because of the number of disciplines involved. In this context, the following illustrative methodologies are selected, developed and presented in this study: - a methodology for automatic measurement of major spatial traffic variables for the present and the future implementation of various ITS functional areas, in general; and - a methodology for real-time link and incident specific freeway diversion in conjunction with freeway incident management, in particular. The first methodology includes the development of a dynamic flow model based on stochastic queuing theory and the principle of conservation of vehicles. An inductive modeling approach adapted here utilizes geometric interpretations of cumulative arrival-departure diagrams which have been drawn directly from surveillance data. The advantages of this model are real-time applicability and transportability as well as ease of use. Analysis results show that the estimates are in qualitative and quantitative agreement with the empirical data measured at 30-second intervals. The analytical expression for link travel times satisfies traffic dynamics where the new form of the equation of conservation of vehicles has been derived. This methodology has potential applicable to automatic traffic control and automatic incident detection. The methodology is then applied to freeway diversion in real-time in conjunction with freeway incident management. The proposed new form of the equation of conservation of vehicles is applied to detect recurring or non-recurring congestion analytically. The principle of conservation of vehicles is applied to develop the concept of progression and retrogression of incident domain, which turns out to be compatible with traditional shock wave traffic mechanism during incidents. The link and incident specific diversion methodology is achieved by using a delay diagram and volume-travel time curves, which can be plotted per link per incident. The use of such graphic aids makes problem solving much easier and clearer. The dynamic traffic flow model developed here can also be applied to estimate travel times during incidents as a function of time. The development of a computer program for freeway diversion concludes this research. / Ph. D.

When implementing an intelligent transportation system (ITS), stakeholders often overlook the importance of evaluating the system once it is in place. Determining the extent to which the objectives of an investment have been met is important to not only the agency involved, but also to other agencies, so that lessons are learned and mistakes are not repeated in future projects. An effective evaluation allows a transit provider to identify and address areas that could use improvement. Agencies implementing ITS investments often have different goals, needs, and concerns that they hope their project will address and consequently the development of a generic evaluation plan is difficult to develop. While it is recognized that the U.S. Department of Transportation has developed guidelines to aid agencies in evaluating such investments, this research is intended to complement these guidelines by assisting in the evaluation of a site specific ITS investment. It presents an evaluation framework and plan that provides a systematic method for assessing the potential impacts associated with the project by defining objectives, measures, analysis recommendations, and data requirements. The framework developed specifically addresses the ITS investment on the OmniLink local route deviation bus service in Prince William County, Virginia, but could be used as a basis for the evaluation of similar ITS investments. The OmniLink ITS investment includes an automatic vehicle location (AVL) system, mobile data terminals (MDTs), and computer-aided dispatch (CAD) technology. / Master of Science

In the driving task, vision, hearing, and the haptic senses are all used by the driver to gather required information. Future Intelligent Transportation Systems components are likely to further increase the volume of information available to or required by the driver, particularly in the case of commercial vehicle operators. The use of alternate modalities to present in-vehicle information is a possible solution to the potential overload of the visual channel. Auditory icons have been shown to improve operator performance and decrease learning and response times, not only in industrial applications, but also as emergency braking warnings. The use of auditory icons in commercial truck cabs has the potential to increase the number of auditory displays that can be distinguished and understood by commercial vehicle operators, and this experiment sought to determine the utility of auditory icons in that situation. Nine auditory icons were evaluated by commercial vehicle operators as they drove an experimental vehicle over public roads. A comparison of the data collected in the truck-cab environment to data collected in a laboratory study on the same auditory icons revealed some differences in the perceived meaning, perceived urgency, and association with the auditory icons' intended meanings between the two conditions. The presence of these differences indicates that driver evaluations of auditory icons can be affected by the environment, and testing should therefore be conducted in a situation that approximates the end-user environment as closely as possible. A comparison of the drivers' brake response times across the three warning conditions (no warning, auditory icon, and soft braking) was also conducted on a closed, secure handling course. Dependent measures included overall brake reaction time and its components, steering response time, time to initial driver action, and categorical measures of driver responses (steering, swerving, braking, and stopping). The results indicated numerically shorter mean response times (on the order of 0.5 seconds for Total Brake Response Time) for the two conditions with warnings, but the differences were not statistically significant. The most likely reason for this lack of significance is the extreme between-subject variability in response times in the no warning condition. An analysis of the response time variance across the three conditions did indicate significantly less variability in operator responses in the two warning conditions. Two of the five dependent measures (Brake Pedal Contact Time and Total Brake Response Time) exhibited significantly reduced variance in the auditory icon warning condition compared to the no warning condition. The soft braking warning condition exhibited significantly reduced variance for four of the dependent measures (Accelerator Reaction Time, Brake Pedal Contact Time, Total Brake Response Time, and First Reaction Time). These results indicate that a soft braking stimulus like that used in this study could potentially prove to be a more effective emergency braking warning than simple auditory warnings alone. / Master of Science

No description available.

Thesis (MScEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Mode choice modelling is an important and versatile tool that can aid decision makers with transit related strategies and scenario planning. The traditional approach to modelling public transport is labour intensive and requires many resources. The expensive nature of developing mode choice models can also act as a deterrent for developing a model. Not having access to a functional mode choice model can force decision makers to make important decisions without having access to proper information. There is therefore a need to provide a simplified solution for developing a functional mode choice model that can be developed and maintained with fewer resources. This research project explores the possibility of developing a simplified alternative approach to public transport modelling that can model mode choice behaviour with the same degree of accuracy as traditional models. The modelling steps employed in this research project were the typical four step demand modelling approach, but the principles employed differ slightly. The focus area of this research project is the development of simplified utility functions and the calibration thereof. Typical mode choice models coincide with many assumptions, variations and uncertainties. In this research project the proposed utility functions are simplified by incorporating most of the assumptions and intangible components of the utility function into a single station to station specific calibration factor. The hypothesis is that a simplified alternative approach to the utility functions can still provide a model that is purpose built and functional. The application of the proposed mode choice model is to model the mode choice between the Gautrain and private vehicles as the major mode of transport.

A lotação do veículo é um dos fatores determinantes para a qualidade do transporte público (TP), pois, além do conforto do passageiro, afeta também a confiabilidade da linha, alterando a velocidade média do veículo. Entretanto, na cidade de São Paulo, Brasil, uma das maiores operações de ônibus do mundo, é difícil se encontrar implantado algum equipamento de contagem automática de passageiros (APC), provavelmente devido aos custos das tecnologias atuais. Esta pesquisa apresenta os resultados de um método de APC utilizando o sensoriamento por Wi-Fi de telefones móveis dos passageiros embarcados num veículo do TP por ônibus. Para este fim, um protótipo de baixo custo foi desenvolvido e instalado na linha 6500-10 entre o Terminal Santo Amaro e o Terminal Bandeira, durante 7 dias da semana em horários de pico e entre pico. Os dados coletados foram analisados através de ferramentas estatísticas e métodos de análise geográficas. Durante o experimento observou-se que o APC foi capaz de detectar a mudança da ocupação do veículo em 85% dos casos, com uma confiança de até 20% e um erro de até 22 passageiros por medida. Através de dados de posição geográfica foi possível gerar matrizes de carregamento, que permitem inferir a origem e o destino dos passageiros em cada viagem, assim como - para todo o período do experimento - indicar os trechos com maior lotação. Por outro lado, o método não apresentou bons resultados saindo dos terminais e quando a ocupação mudou repentinamente, requerendo estudos posteriores para refinar o algoritmo apresentado. Da mesma maneira, ainda não há como generalizar o método para toda operação, pois, o espaço amostral estudado foi pequeno, deixando como sugestão para pesquisas futuras o aprimoramento deste sistema. / The crowdedness of a vehicle is one of the main quality factor of the public transportation (TP) quality, since, besides the comfort, also affect the reliability of the line, changing its average speed. However, the city of São Paulo, Brazil, one of the biggest bus operations of the world, it is difficult to find any automatic passenger counter (APC) equipment deployed, probably due the costs of current technologies. This research shows the results of an APC technology by the sensing of the Wi-Fi signal of smartphones that are boarded in a vehicle on TP by bus. Therefore, a prototype was developed and deployed on the line 6500-10 between the Terminal Santo Amaro and the Terminal Bandeira, during 7 working days of the week on peak and off-peak hours. was analyzed with statistical and geographical tools. During the experiment, it was observed that the Wi-Fi APC was capable of estimate the occupancy of the vehicle 85% of the cases, with a significance level up to 20% and an error up to 22 passengers per estimation. Through the geographical analysis it was generated load matrices, that allow to infer the origin and destination of the passenger in each trip, indicating the sections along the route where were more boarding and alighting. On the other hand, the method did not perform well when coming out of the final stops and when the crowdedness changed suddenly, requiring further analysis to understand how to deal better under these circumstances. Likewise, due to the limited sample utilized in this research, we cannot generalize the results presented, pressing the need for new researches on different operation scenarios.

O ônibus ainda é o modo de transporte público mais usado nas cidades brasileiras, mesmo aquelas que contam com sistemas sobre trilhos extensos. Já centenários, os sistemas de ônibus urbanos ainda se debatem na peleja diária da competição com os demais veículos e na busca de uma imagem mais favorável perante a seus usuários e à população. O advento do ferramental de Sistemas Inteligentes de Transporte (ITS) ofereceu a oportunidade de que esses sistemas pudessem contar com instrumentos de Planejamento, Programação, Monitoração e Controle Operacional próximos àqueles que os sistemas metroferroviários já dispõem há muitas décadas. Entre os vários avanços proporcionados pelo emprego de ITS no campo operacional, destacam-se as intervenções operacionais em tempo real, isto é, a aplicação de medidas que buscam oferecer ou restabelecer a regularidade e a eficiência da operação dos ônibus urbanos frente a contingências que eles enfrentam diariamente. Este trabalho objetiva fazer uma resenha das diversas opções de intervenções estudadas no campo acadêmico e executar simulações de três modalidades dessas estratégias. Foi construída uma rede reproduzindo um trecho de Corredor de ônibus na cidade de São Paulo e simulada a operação de uma linha de alta demanda, com base nos dados reais da operação, do trânsito (semáforos) e velocidades de percurso dos ônibus. A simulação, por sua vez, permitiu apurar os benefícios propiciados pelas intervenções testadas, chegando aos ganhos de tempos nas viagens e o possível aumento de oferta de veículos sem aumento da frota. Além de comparar os resultados entre os tipos de intervenção, foi verificada a sensibilidade dos resultados de cada estratégia a mudanças na intensidade de sua aplicação.Os resultados enquadram-se na faixa dos resultados obtidos nos diversos experimentos acadêmicos analisados. Dentro das expectativas, a intervenção das Meias Viagens (\"deadheading\") apresentou melhores resultados nos ganhos de tempos de viagem variando entre 8,5% e 12,9%, secundados pelas Paradas Limitadas (\"skip-stop\") variando entre 2,9% e 4,7%, enquanto a Linha Expressa apresentou resultados menores, motivados, principalmente, pelas limitações da extensão do trecho analisado. / Buses are still the most common transit mode in Brazilian cities even in those that count with extensive rail systems. Century old city bus operations still struggle daily to compete with other road vehicles while trying to gain a better image before its users and the general public. The arrival of Intelligent Transportation System (ITS) solutions brought to these systems the opportunity of counting on Operational Planning, Programing, Monitoring and Control like those already used by rail transit for decades. Among several improvements possible using ITS real time intervention during operation stands out. This enables the application of measures to offer or restore regularity and efficiency of bus services in face of contingencies faced daily. This paper aims to review different options of intervention reported in academic publications and to perform simulations of three of these strategies. A network was modeled duplicating a real Sao Paulo bus corridor section on which a high demand bus line operation, based on actual operation data, traffic, traffic lights and bus speeds, was studied. The simulation, in turn, allowed us to assess the benefits of each alternative intervention tested by determining travel time gains and the increase in bus service supply without increasing the operating fleet. Besides comparing results between intervention types the sensitivity of each one\'s results to strategy application intensity was also reached. The final experiments results fall within the range of those obtained in several other academic studies analyzed. Within the expectations, the deadheading intervention presented better results in travel time gains ranging from 8.5% to 12.9%, followed by the skip-stop, ranging from 2, 9% and 4.7%, while the Express Line presented lower results motivated, mainly, by the limitations of the extension of the analyzed section

Dans cette thèse, nous nous intéressons au problème du suivi en convoi, désigné en anglais par le terme platooning, où un train de robots essaie de suivre un chemin décrit par le leader. Ce chemin, n'étant pas prédéfini mais généré au cours du suivi, est inconnu de tous les robots suiveurs. Dans ce travail, nous choisissons une approche décentralisée locale où chaque robot du convoi observe son voisinage et calcule son contrôle de façon à avoir un suivi stable (absence d'oscillations) et précis (erreur latérale aussi faible que possible). Cette thèse étudie plus précisément le comportement latéral d'un robot du convoi et propose deux contrôleurs s'appuyant sur la mémorisation du chemin suivi par son prédécesseur. Un premier algorithme de contrôle Memo-LAT (Memorization and Look-Ahead Target) calcule une commande latérale continue en utilisant une loi de contrôle analytique. La stabilité de Memo-LAT n'étant pas toujours garantie, nous proposons l'algorithme de contrôle NOC (Non-Oscillatory Convergence) qui prend en compte la courbure du chemin à suivre dans le calcul du comportement latéral. NOC combine une approche géométrique avec une recherche heuristique pour calculer une commande discrète permettant au robot de suivre avec précision le chemin de son prédécesseur sans oscillation. / This thesis deals with the platooning problem which aims to concieve a control algorithm allowing a convoy of vehicles to follow their leader's path. This path, which is initially undefined and unknown to all the following robots, is generated as the leader moves. In this thesis, we choose a local decentralized approach in which each robot of the platoon uses its local perceptions to compute its own commands aiming to achieve a stable (no oscillations) and precise (with a lateral error as small as possible) platooning. More precisely, this thesis studies the lateral behavior of a platoon's robot and introduces two controllers based on the memorization of the robot's predecessor's path. The first algorithm, Memo-LAT (Memorization and Look-Ahead Target), computes a continuous lateral command using an analytic control law. As the stability of Memo-LAT is not always guaranteed, we present NOC (Non-Oscillatory Convergence), a control algorithm which takes into account the path's curvature in the robot's lateral behavior's computation. NOC combines a geometric approach to a heuristic search method to compute a discrete command allowing the robot to follow precisely and without oscillations its predecessor's path

Macroscopic fundamental diagram is the concept of the highest importance in traffic flow theory used for development of network-wide control strategies. Previous studies showed that so called Arterial Fundamental Diagrams (AFDs) properly depict relationships between major macroscopic traffic variables on urban arterials. Most of these studies used detector’s occupancy as a surrogate measure to represent traffic density. Nevertheless, detector’s occupancy is not very often present in the field data. More frequently, field data from arterial streets provide performance metrics measured at the stop lines of traffic signals, which represent a hybrid of flow and occupancy. When such performance measures are used in lieu of density, the outcomes of the relationships between macroscopic fundamental variables can be confusing. This study investigates appropriateness of using degree of saturation, as a representative surrogate measure of traffic density, obtained from an adaptive traffic control system that utilizes stop-line detectors, for development of AFDs. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Vehicular Ad hoc NETworks (VANETs) are a subclass of Mobile Ad hoc NETworks and represent a relatively new and very active field of research. VANETs will enable in the near future applications that will dramatically improve roadway safety and traffic efficiency. There is a need to increase traffic efficiency as the gap between the traveled and the physical lane miles keeps increasing. The Dynamic Traffic Assignment problem tries to dynamically distribute vehicles efficiently on the road network and in accordance with their origins and destinations. We present a novel dynamic decentralized and infrastructure-less algorithm to alleviate traffic congestions on road networks and to fill the void left by current algorithms which are either static, centralized, or require infrastructure. The algorithm follows an online approach that seeks stochastic user equilibrium and assigns traffic as it evolves in real time, without prior knowledge of the traffic demand or the schedule of the cars that will enter the road network in the future. The Reverse Online Algorithm for the Dynamic Traffic Assignment inspired by Ant Colony Optimization for VANETs follows a metaheuristic approach that uses reports from other vehicles to update the vehicle’s perceived view of the road network and change route if necessary. To alleviate the broadcast storm spontaneous clusters are created around traffic incidents and a threshold system based on the level of congestion is used to limit the number of incidents to be reported. Simulation results for the algorithm show a great improvement on travel time over routing based on shortest distance. As the VANET transceivers have a limited range, that would limit messages to reach at most 1,000 meters, we present a modified version of this algorithm that uses a rebroadcasting scheme. This rebroadcasting scheme has been successfully tested on roadways with segments of up to 4,000 meters. This is accomplished for the case of traffic flowing in a single direction on the roads. It is anticipated that future simulations will show further improvement when traffic in the other direction is introduced and vehicles travelling in that direction are allowed to use a store carry and forward mechanism. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection