Dissertations / Theses: 'Intersection Delay' – Grafiati (2024)

Abstract:

Thesis (M.S.)--University of Akron, Dept. of Civil Engineering, 2009.
"May, 2009." Title from electronic thesis title page (viewed 8/2/2009) Advisor, Ping Yi; Committee members, William H. Schneider IV, Anil Patnaik; Department Chair, Wieslaw K. Binienda; Dean of the College, George K. Haritos; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

Abstract:

Estimation of real-time travel times on arterial streets has been a challenging task due to the intersection control delay as well as bottleneck delay from the downstream link. Therefore, few transportation professionals have conducted research at utilizing the dynamic flow methods to estimate travel times on arterial street networks.This thesis is to develop dynamic flow algorithms that estimates the real-time travel time on an arterial street network by utilizing the traffic information obtained from detectors. A modified method to the one adopted in HCM2000 in computing the intersection control delay is developed and utilized to estimate the real-time travel time for a short-time interval update under non-incident and incident situations. Simulation model is developed in CORSIM to validate developed algorithms under different traffic situations.
Master of Science

Abstract:

Assuming that vehicle connectivity technology matures and connected vehicles hit the market, many of the running vehicles will be equipped with highly sophisticated sensors and communication hardware. Along with the goal of eliminating human distracted driving and increasing vehicle automation, it is necessary to develop novel intersection control strategies. Accordingly, the research presented in this dissertation develops an innovative system that controls the movement of vehicles using cooperative cruise control system (CACC) capabilities entitled: iCACC (intersection management using CACC).In the iCACC system, the main assumption is that the intersection controller receives vehicle requests from vehicles and advises each vehicle on the optimum course of action by ensuring no crashes occur while at the same time minimizing the intersection delay. In addition, an innovative framework has been developed (APP framework) using the iCACC platform to prioritize the movements of vehicles based on the number of passengers in the vehicle. Using CACC and vehicle-to-infrastructure connectivity, the system was also applied to a single-lane roundabout. In general terms, this application is considered quite similar to the concept of metering single-lane entrance ramps. The proposed iCACC system was tested and compared to three other intersection control strategies, namely: traffic signal control, an all-way stop control (AWSC), and a roundabout, considering different traffic demand levels ranging from low to high levels of congestion (volume-to-capacity ration from 0.2 to 0.9). The simulated results showed savings in delay and fuel consumption in the order of 90 to 45 %, respectively compared to AWSC and traffic signal control. Delays for the roundabout and the iCACC controller were comparable. The simulation results showed that fuel consumption for the iCACC controller was, on average, 33%, 45% and 11% lower than the fuel consumption for the traffic signal, AWSC and roundabout control strategies, respectively.In summary, the developed iCACC system is an innovative system because of its ability to optimize/model different levels of vehicle automation market penetrations, weather conditions, vehicle classes/models, shared movements, roundabouts, and passenger priority. In addition, the iCACC is capable of capturing the heterogeneity of roadway users (cyclists, pedestrians, etc.) using a video detection technique developed in this dissertation effort. It is anticipated that the research findings will contribute to the application of automated systems, connected vehicle technology, and the future of driverless vehicle management. Finally, the public acceptability of the new advanced in-vehicle technologies is a challenging task and this research will provide valuable feedback for researchers, automobile manufacturers, and decision makers in making the case to introduce such systems.
Ph. D.

Abstract:

With the introduction of different forms of adaptive and actuated signal control, there is a need for effective evaluation tools that can capture the intricacies of real-life applications. While the current state-of-the-art analytical procedures provide simple approaches for estimating delay, queue length and stops at signalized intersections, they are limited in scope. Alternatively, several microscopic simulation softwares are currently available for the evaluation of signalized intersections. The objective of this dissertation is fourfold. First, it evaluates the consistency, accuracy, limitations and scope of the alternative analytical models. Second, it evaluates the validity of micro simulation results that evolve as an outcome of the car-following relationships. The validity of these models is demonstrated for idealized hypothetical examples where analytical solutions can be derived. Third, the dissertation expands the scope of current analytical models for the evaluation of oversaturated signalized intersections. Finally, the dissertation demonstrates the implications of using analytical models for the evaluation of real-life network and traffic configurations.This dissertation compared the delay estimates from numerous models for an undersaturated and oversaturated signalized intersection considering uniform and random arrivals in an attempt to systematically evaluate and demonstrate the assumptions and limitations of different delay estimation approaches. Specifically, the dissertation compared a theoretical vertical queuing analysis model, the queue-based models used in the 1994 and 2000 versions of the Highway Capacity Manual, the queue-based model in the 1995 Canadian Capacity Guide for Signalized Intersections, a theoretical horizontal queuing model derived from shock wave analysis, and the delay estimates produced by the INTEGRATION microscopic traffic simulation software. The results of the comparisons for uniform arrivals indicated that all delay models produced identical results under such traffic conditions, except for the estimates produced by the INTEGRATION software, which tended to estimate slightly higher delays than the other approaches. For the random arrivals, the results of the comparisons indicated that the delay estimates obtained by a micro-simulation model like INTEGRATION were consistent with the delay estimates computed by the analytical approaches.In addition, this dissertation compared the number of stops and the maximum extent of queue estimates using analytical procedures and the INTEGRATION simulation model for both undersaturated and oversaturated signalized intersections to assess their consistency and to analyze their applicability. For the number of stops estimates, it is found that there is a general agreement between the INTEGRATION microscopic simulation model and the analytical models for undersaturated signalized intersections. Both uniform and random arrivals demonstrated consistency between the INTEGRATION model and the analytical procedures; however, at a v/c ratio of 1.0 the analytical models underestimate the number of stops. The research developed an upper limit and a proposed model for estimating the number of vehicle stops for oversaturated conditions. It was demonstrated that the current state-of-the-practice analytical models can provide stop estimates that far exceed the upper bound. On the other hand, the INTEGRATION model was found to be consistent with the upper bound and demonstrated that the number of stops converge to 2.3 as the v/c ratio tends to 2.0. For the maximum extent of queue estimates, the estimated maximum extent of queue predicted from horizontal shock wave analysis was higher than the predictions from vertical deterministic queuing analysis. The horizontal shock wave model predicted lower maximum extent of queue than the CCG 1995 model. For oversaturated conditions, the vertical deterministic queuing model underestimated the maximum queue length. It was found that the CCG 1995 predictions were lower than those from the horizontal shock wave model. These differences were attributed to the fact that the CCG 1995 model estimates the remaining residual queue at the end of evaluation time. A consistency was found between the INTEGRATION model and the horizontal shock wave model predictions with respect to the maximum extent of queue for both undersaturated and oversaturated signalized intersections.Finally, the dissertation analyzed the impact of mixed traffic condition on the vehicle delay, person delay, and number of vehicle stops at a signalized intersection. The analysis considered approximating the mixed flow for equivalent homogeneous flows using two potential conversion factors. The first of these conversion factors was based on relative vehicle lengths while the second was based on relative vehicle riderships. The main conclusion of the analysis was that the optimum vehicle equivalency was dependent on the background level of congestion, the transit vehicle demand, and the Measure of Effectiveness (MOE) being considered. Consequently, explicit simulation of mixed flow is required in order to capture the unique vehicle interactions that result from mixed flow. Furthermore, while homogeneous flow approximations might be effective for some demand levels, these approximations are not consistently effective.
Ph. D.

Abstract:

Esta pesquisa propõe um método que compara o desempenho de interseções através de quatro medidas: número de conflitos de tráfego, capacidade integral de processamento, atraso e espera média e custo de construção. O método foi aplicado a um grupo de seis interseções, três configurações alternativas e três variações do conceito trevo vazado, conceito básico adotado na grande maioria das interseções em nível de rodovias rurais brasileiras. Em paralelo, desenvolveu-se um método de conflitos baseado no conceito de conflito equivalente. O programa INTEGRATION foi utilizado no cálculo da capacidade integral de processamento e atraso e espera média. É apresentada uma planilha simplificada de custo de construção para obtenção dos orçamentos das interseções. Uma comparação de desempenhos é realizada para uma condição particular de capacidade de tráfego. Como o método permite a parametrização, ele pode também ser utilizado para avaliar outras condições operacionais. Conclui-se que, para as condições operacionais avaliadas, as configurações do tipo trevo vazado tem desempenho inferior a duas alternativas investigadas na pesquisa, a rotatória e a rotatória alongada com entrelaçamento.
This research proposes a method to compare road intersection performances through four measures: number of traffic conflicts, processing integral capacity, average delay and waiting time and construction cost. The method was applied to a group of six intersections, three alternative configurations of intersections and three variations of the \"trevo vazado\" concept, which is usual basic concept for projects of Brazilian road intersection. At the same time, a traffic conflict method, based on equivalent conflict concept, was developed. The INTEGRATION software was used to calculate the processing integral capacity and the average delays and waiting times. A simple construction cost table for estimating the construction cost of the intersections is presented. A performance comparison of the various intersection configurations is also presented for a particular level of processing capacity. As the method permits parametrization, it can be used to evaluate other operational conditions. It is concluded that, for the evaluated operational conditions, the configurations of the \"trevo vazado\" have an inferior performance than the roundabout and the along roundabout.

Abstract:

While weaving maneuvers occur on every type of roadway, most studies have focused on freeway maneuvers. Weaving occurring on non-freeway facilities, such as arterial streets, can cause significant operational problems. Arterial streets weaving typically occur when vehicles coming from a side street at an upstream intersection attempt to enter the main street from one side to reach access points on the opposite site at a downstream intersection by crossing one or more lanes. This dissertation investigates the type of problems occurring on arterial streets due to the weaving movements and recommends a new design to alleviate weaving on arterial streets. Firstly, the dissertation examined the different weaving movements occurring between two close-spaced intersections at two sites in Florida and explained the breakdown conditions caused by the weaving movements at the two sites. Secondly, the dissertation proposed a new design, Right Turn Split (RTS), to alleviate the delay caused by the weaving movements. The new design proposed separating the worst weaving movement entering the arterial from the other movements and providing a separate path for this movement. The new method is easy to implement and does not require much right of way. Thirdly, the dissertation compared two microscopic models, SimTraffic and VISSIM, to choose the most suitable model to be used to study the operational benefits of the RTS design. Based on the results of the comparison, it was decided to use SimTraffic for the analysis. Fourthly, the dissertation proposed a new calibration and validation procedure for microscopic simulation models. The procedure was applied on SimTraffic using the traffic data from the two studied sites. The proposed procedure appeared to be properly calibrating and validating the SimTraffic simulation model. Finally, the calibrated and validated model was used to study the operational benefits of the RTS design. Using a wide range of geometric and volume conditions, 729 before and after pairs were created to compare the delay of similar scenarios before and after applying the RTS design. The results were analyzed graphically and statistically. The findings of the analysis showed that the RTS design provided lower delay on the arterial street than the original conditions.
Ph.D.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Civil Engineering

Abstract:

Increasing demand for road freight has lead to a widespread adoption of more-productive large freight vehicles (LFVs), such as B-Doubles, by Australia's road freight industry. Individual LFVs have a greater potential to impact traffic efficiency through their greater length and poorer longitudinal performance. However, this is offset to an extent as fewer vehicles are required to perform a given freight task on a tonne-km basis. This research has developed a means of characterising the effects that large freight vehicles have on the performance of an urban arterial corridor managed by signalised intersections. A corridor-level microsimulation model was developed from first principles, which modelled the longitudinal performance of individual vehicles to a greater accuracy than most existing traffic simulation software does. The model was calibrated from traffic counts and GPS-equipped chase car surveys conducted on an urban arterial corridor in Brisbane's southern suburbs. The model was applied to various freight policy and traffic management scenarios, including freight vehicle mode choice, lane utilisation and traffic signal settings; as well as the effectiveness of green time extension for approaching heavy vehicles. Benefits were able to be quantified in terms of reduced travel times and stop rates for both heavy and light vehicles in urban arterial corridors.

Abstract:

Die vorliegende Dissertationsschrift widmet sich zwei Zielen: Mittels Induktionsschleifen-Detektoren einerseits die Verkehrsregelung an Knotenpunkten durch die Minimierung von Fahrzeughalten zu verbessern, und andererseits eine Veränderung der Verkehrsqualität durch die Schätzung von Kfz-Wartezeiten automatisiert zu erheben.Im ersten Teil wird ein modellbasiertes Steuerverfahren entwickelt, das Grünzeiten verkehrsabhängig und lokal anpasst. Es kann sehr gut in eine übergeordnete Steuerung zur Koordinierung in Verkehrsnetzen eingebunden werden und überlässt dieser die Optimierung von Phasenfolgen, Umlauf- und Versatzzeiten.Um auch bei hohen Auslastungen Kapazitäten bestmöglich zu nutzen, priorisiert es zunächst die Leerung von Warteschlangen. Anschließend erfolgt die Anpassung der Grünzeiten zwischen einer minimalen und maximalen Dauer so, dass Fahrzeughalte minimiert werden. Dafür werden Detektoren in ausreichender Entfernung im Zufluss einer Kreuzung verwendet, um Fahrzeugankünfte an der Haltelinie für die aktuelle und die nächste Phase zu prognostizieren. Bei der sich anschließenden Bilanzierung potenzieller Fahrzeughalte und der Wahl des günstigsten Umschaltzeitpunktes kann auf zusätzliche Modellannahmen verzichtet werden. Die Simulationsergebnisse zeigen, dass bei einer Minimierung der Fahrzeughalte gleichzeitig eine Reduktion von Wartezeiten möglich ist.Im zweiten Teil werden Kfz-Wartezeiten auf Basis der meist bereits vorhandenen Induktionsschleifen-Detektoren im Zufluss und im Abfluss einer Kreuzung geschätzt. Dafür werden die Zeitpunkte der Fahrzeugüberfahrten an einem Zufluss- und einem Abflussquerschnitt getrennt gemessen werden. Aus ihnen wird jeweils ein mittlerer Überfahrzeitpunkt ermittelt und nach Berücksichtigung der freien Fahrzeit eine mittlere Wartezeit geschätzt. Messintervalle an beiden Querschnitten, die um die mittlere freie Fahrzeit versetzt sind, sowie eine unbedingte Warteschlangenleerung am Ende einer Messung sollen sicherstellen, dass potenziell dieselben Fahrzeuge erfasst werden. Auf eine Fahrzeugwiedererkennung und damit auf eine Ausrüstung mit zusätzlicher Technik kann dadurch verzichtet werden.Damit sich das Verfahren für den Praxiseinsatz eignet, muss es möglichst robust gegenüber zufälligen Detektorfehlern sein. Dafür wird ein Fehlermodell entwickelt und mögliche Abweichungen gegenüber einer korrekten Messung untersucht. Aufgrund der unabhängigen Berechnung von mittleren Überfahrzeiten aus der getrennten Messung im Zufluss und im Abfluss zeigt sich, dass zufällige Fehler nicht zu systematischen Abweichungen in der Wartezeitschätzung führen.

Abstract:

This research has three parts. Part 1: The Policy on Geometric Design of Highways and Street provides 5 methods of superelevation (e) distribution. Many states use methods 2 and 5 for low speed, urban and rural high-speed facilities. Method 5 aims to address speed variations; but is complicated, computationally intractable and may violate design consistency. Design recommendation by NCHRP439 accounts for speed variation, tractable; but is cumbersome along with irregular/step-wise design curves. New reliability based e distribution method is developed that addresses the speed variation; which is simple in determining and evaluating acceptable required e rates. At 95% level of reliability, the e rate obtained is lower than that from current practice resulting in cost savings. Part 2: Current practice/research does not address safety issue of the left-turn-bay at high degree of saturation (x). Left-Turn-Bay distance has three components: clearance, breaking to a stop and queue. The variation in the queue length reduces clearance and breaking distance resulting in unsafe breaking. Failure = clearance plus breaking distance < demand. The reliability of the left-turn-bay defined as the availability of the three components for left-turning vehicles to complete clearance and breaking maneuver safely; measured as increase in the deceleration rate over limit of 11.2ft/s2, safety index and probability of failure. Results show that at 95% reliability, current design practice fails when x exceeds 50%. Part 3: Current practice uses mean traffic volumes (Vd) as input for traffic signal control at roadway intersections. Variations in traffic flows affect the performance of intersection measured by the delay per vehicle traversing the intersection in seconds. Peak hour factor (PHF), the hourly volume divided by the peak 15-min flow rate within the peak hour is adopted by Highway Capacity Manual (HCM) to control surge. HCM suggests PHF design value of 0.92 for urban and 0.88 for rural areas. Fixed PHF may lead to increase in delay. Effects of variation of peak hour volumes on intersection signal delays are examined with large data. A new model is developed for PHF and Vd and used in signal timing to minimize intersection delay. The results show that the assumption of Poisson distribution for Vd is not reliable; delay reduction of 6.2 seconds per vehicle is achieved. Annual savings in travel time, fuel consumption and emissions cost is estimated in billions of dollars.

Abstract:

La congestión vehicular se ha convertido en una constante en la vida citadina y Lima no es la excepción. Sin embargo, existen acciones que pueden ser implementadas para minimizar el tiempo que se pierde al circular por vías de alto tránsito, especialmente durante horas pico, como es el caso de la red constituida por las avenidas Faustino Sánchez Carrión. y La Marina, desde la Av. Gregorio Escobedo hasta la Av. Antonio José de Sucre.En ese contexto, el propósito del presente trabajo es brindar una alternativa de gestión de la oferta vial que contribuya con la optimización de los indicadores de medición del tráfico; entre ellos, el grado de saturación, el nivel de servicio de las intersecciones que forman parte de la investigación y las demoras por tiempo de espera. Para ello, se hace uso de Synchro 8, un software de simulación que sirve de soporte para la generación del modelo de solución, efectuado a nivel mesoscópico.Synchro es compatible con el Highway Capacity Manual - HCM 2000 y 2010; pero además, cuenta con una serie de herramientas que le permiten incorporar su propia técnica de análisis. En el caso de este proyecto, la evaluación del tráfico se desarrolla mediante la Metodología del Automóvil de HCM 2010; sin considerar el análisis de peatones ni ciclistas.Los resultados obtenidos demuestran que es posible optimizar el tráfico vehicular a través del uso correcto de simuladores de tránsito y no solo con intervenciones geométricas de gran escala o excesiva inversión en nueva infraestructura.
Traffic congestion has become a constant in city life, and Lima is not the exception. However, there are actions that can be implemented to minimize the time lost when traveling on high-traffic routes, especially during rush hours, such as the case of the road network formed by the Faustino Sánchez Carrión and La Marina avenues, from Gregorio Escobedo Ave. to Antonio José de Sucre Ave.In that context, the purpose of this project is to provide an alternative of road offer management which contributed to improving traffic measurement indicators; among them, saturation degree, intersections level of service that are part of the research, and delays due to waiting time. In doing so, Synchro 8 is used. This simulation software functions as a support for the solution model generation, which is performed at the mesoscopic level.Synchro is compatible with the Highway Capacity Manual - HCM 2000 and 2010; but also, it has a set of tools that allow it to incorporate its own analysis technique. In the case of this project, traffic evaluation is developed on the basis of vehicular operation system by means of the HCM 2010 Automobile Methodology; that is, the pedestrians and cyclists analysis are not taken into consideration.The results obtained show that it is possible to optimize vehicular traffic through the correct use of traffic simulators and not only through large-scale geometric interventions, or with excessive investment in new infrastructure.
Tesis

Abstract:

This dissertation aimed to improve travel time estimation for the purpose of transportation planning by developing a travel time estimation method that incorporates the effects of signal timing plans, which were difficult to consider in planning models. For this purpose, an analytical model has been developed. The model parameters were calibrated based on data from CORSIM microscopic simulation, with signal timing plans optimized using the TRANSYT-7F software. Independent variables in the model are link length, free-flow speed, and traffic volumes from the competing turning movements. The developed model has three advantages compared to traditional link-based or node-based models. First, the model considers the influence of signal timing plans for a variety of traffic volume combinations without requiring signal timing information as input. Second, the model describes the non-uniform spatial distribution of delay along a link, this being able to estimate the impacts of queues at different upstream locations of an intersection and attribute delays to a subject link and upstream link. Third, the model shows promise of improving the accuracy of travel time prediction. The mean absolute percentage error (MAPE) of the model is 13% for a set of field data from Minnesota Department of Transportation (MDOT); this is close to the MAPE of uniform delay in the HCM 2000 method (11%). The HCM is the industrial accepted analytical model in the existing literature, but it requires signal timing information as input for calculating delays. The developed model also outperforms the HCM 2000 method for a set of Miami-Dade County data that represent congested traffic conditions, with a MAPE of 29%, compared to 31% of the HCM 2000 method. The advantages of the proposed model make it feasible for application to a large network without the burden of signal timing input, while improving the accuracy of travel time estimation. An assignment model with the developed travel time estimation method has been implemented in a South Florida planning model, which improved assignment results.

Abstract:

This document discusses an investigation into the relationship between stopped and control delay for through lane groups at actuated signalized intersections. The research was motivated by potential inconsistencies in the level-of-service thresholds between the 1994 and 1997 Highway Capacity Manuals. The research identified four existing analytical models that describe the stopped to control delay relationship, Reilly-Gardner, Akcelik, Teply, and Quigora-Bullock.

The research also identified five variables as having an impact on the stopped to control delay relationship, namely the delay magnitude, controller type, number of lanes, percent split, and approach speed. Focusing on actuated controllers, a comprehensive simulation-based dataset was developed using CORSIM that allowed for direct comparison of the existing analytical models noted above. None of the four models proved capable of describing all the factors that affect the stopped to control delay relationship. The CORSIM dataset was also used to test the consistency of the 1994 and 1997 level-of-service thresholds, which were found to be inconsistent. Using control delay and the 1997 thresholds tended toward a worse level-of-service than using stopped delay with the 1994 thresholds.

Using the same CORSIM dataset, three new analytical models describing the stopped to control delay relationship were developed. Both the existing and the newly developed analytical models were validated using field data. The validation steps showed that one of the newly developed models, called the Multivariate-Linear Model, provided the best overall description of the stopped to control delay relationship. This model was used to develop a new set of level-of-service thresholds for use with control delay. This new set of thresholds was shown to be more consistent with the 1994 Highway Capacity Manual stopped delay thresholds than the 1997 Highway Capacity Manual control delay thresholds.

Abstract:

Istraživanje koje je sprovedeno u okviru disertacije poslužilo je za definisanje matematičkog modela koji se može primeniti u postupku određivanja nivoa usluge za nesignalisane pešačke prelaze. Formirani model za proračun stepena propuštanja pešaka u uslovima lokalnog odvijanja saobraćaja zavisi od protoka pešaka i vozila, strukture saobraćajnog toka (učešće autobusa i teretnih vozila) i smera kretanja vozila na lokaciji pešačkog prelaza. U okviru disertacije izvršena je analiza pešačkih intervala prilikom prelaska kolovoza. Uporednom analizom prihvatljivih i kritičnih intervala dobijen je model ponašanja pešaka u zavisnosti od karakteristika lokacije nesignalisanog pešačkog prelaza. Utvrđena je zavisnost između dužine prihvaćenih intervala pešaka prilikom prelaska kolovoza i uslova odvijanja saobraćaja, polnih karakteristika pešaka i broja pešaka koji prelaze kolovoz na nesignalisanom pešačkom prelazu.
The study, which was conducted within the thesis, has served to define a mathematical model that can be applied in the process of determining the level of service at unsignalized pedestrian crossings. The formed model for motorist yield rate, in terms of the local pedestrian traffic flow, depends on pedestrian and vehicular flow rate, traffic flow structure (the share of buses and freight vehicles), and vehicle moving at the location of a pedestrian crossing. The pedestrian gap acceptance behaviour has also been analysed. Comparative analysis of acceptable and critical pedestrian gap was conducted. Model of pedestrian behaviour, which depending on the site characteristics, was formed and it has been proven a correlation between the length of the accepted pedestrian gaps and the roadway and traffic conditions, gender characteristics and the number of pedestrians at unsignalized crossings.

Abstract:

This thesis consists of five scientific articles oriented towards capacity. Managing capacity constraints with associated delays is a big issue at new design as well as at trimming existing traffic facilities. In larger Swedish cities these challenges have become more and more important as a result of growing traffic demand due to rapid population increase.Models for estimating capacity and delay are available, but not many are calibrated for Swedish conditions due to the high effort required. This thesis documents development and calibration of new models for motorway links, entry and exit lanes and weaving areas and an developed space-time model with the ability to calculate queue length, delay, etc.The first article is focused on identifying weaknesses in the former Swedish capacity method for motorways, and development of new models overcoming these shortcomings. The development includes new models for jam density at queue, capacity in weaving areas and fundamental flow-density relationships for 15 different highway types for inclusion in the new Swedish capacity manual.The second article describes the development of a Swedish motorway space-time model to estimate travel times and queues in oversaturated conditions based on the American FREEVAL model in Highway Capacity Manual 2010 (HCM 2010). Calibration and validation of the model has been performed with data from the Motorway Control System (MCS) in Stockholm. A good correspondence was obtained for most cases, but further calibration and validation efforts are required for entry and exit lanes.The third article describes further development of the intersection model in the Swedish microscopic model “Rural Traffic Simulator (RuTSim). This is a continuation of the work documented in the author’s licentiate thesis published in 2002. The development focused on simulation of intersections using a new concept on lane use not included in the old RuTSim model. The model describes Swedish rural intersections with flared approaches providing a non-discreet lane use due to vehicle types in queue. New data for calibration and validation data was also generated. The validation results showed good correspondence between simulated and empirical delay results. The new intersection model is now implemented in RuTSim, providing new tools for estimation of capacity, delay and queue length already included in Swedish guidelines and capacity manuals/software (Capcal).The fourth article describes the development of a new capacity model for roadwork zones. Focus is on the resulting capacity of one lane due to several reduction factors. These factors include impacts of closed road shoulders, reduction of number of lanes, diversion of traffic to the opposite carriageway, commuting traffic, length of work zone, lane width and type of road work. The first two correction factors were successfully validated in a full-scale test on the E6 motorway in Gothenburg.The fifth article describes development and implementation of a new harmonization algorithm for MCS systems on motorways designed to increase bottleneck capacity and throughput. Two different models were developed, one of which was implemented in the existing MCS system on E4 Södertäljevägen south of Stockholm. Full-scale trials were carried out with a model based on trigger levels in terms of flow. The second model based on the difference in the variance of speed during two following time periods was tested offline also with very good results.

QC 20160429

Abstract:

Currently there are several methods to measure the performance of surface streets, but their capabilities in dynamically estimating vehicle delay are limited. The objective of this research is to develop a method to automate traffic delay estimation in real-time using existing field traffic data collection technologies. This research has focused on method and algorithm development that can be applied to existing technologies. Two algorithms were developed to run automatically using Microsoft Excel and Visual Basic to calculate traffic delay from data collected from existing vehicle detection. The algorithms were developed using computer modeling software to simulate different lane configurations. The lane configurations tested were through-only lanes, through lanes with a midblock driveway, and through lanes with a turning bay. Different levels of volumes were simulated for each of the lane configurations. Results were promising for each lane configuration. The through-only configuration showed excellent results with maximum errors less than 3 seconds per vehicle for each test. The through lanes with the driveways test was evaluated using added detection at the driveway locations and no detection at the driveways. Results using the driveway sensors had 93 percent of the calculated average delays with less than 5 seconds per vehicle of error. Results without the driveway sensors had 84 percent of the calculated average delays with less than 5 seconds of error. Results for the turning bay configuration had 94 percent of the calculated turning bay results with less than 5 seconds per vehicle of error. It is recommended to conduct a hardware-in-loop analysis to make certain the algorithms developed in this study perform as expected in a dynamic operation.

Abstract:

Alternative intersections and interchanges, such as the diverging diamond interchange (DDI), the restricted crossing u-turn (RCUT), and the displaced left-turn intersection (DLT), have the potential to both improve safety and reduce delay. However, partially due to lingering questions about analysis methods and service measures for these designs, their rate of implementation remains low. This research attempts to answer three key questions. Can alternative intersections and interchanges be incorporated into the existing level of service and service measure schema, or is a new service measure with an updated level of service model required? Is the behavior of drivers at alternative intersections fundamentally similar to those at conventional intersections, such that traffic microsimulation applications can accurately model the behaviors observed in the field? Finally, is the planning level tool made available through FHWA an accurate predictor of the relative performance of various alternatives, or is an updated tool necessary?Discussion and case study analysis are used to explore the existing level of service and service measure schema. The existing control delay measure is recommended to be replaced with a proposed junction delay measure that incorporates geometric delay, with the existing level of service schema based on control type recommended to be replaced by a proposed schema using demand volume. A case study validation of micro- and macroscopic analysis methods is conducted, finding the two microscopic methods investigated to match field observed vehicle delays within 3 to 7 seconds for all designs tested, and macroscopic HCM method matching within 3 seconds for the DDI, 35 seconds for the RCUT, and 130 seconds for the DLT design. Taking the critical lane analysis method to be a valid measure of operations, the demand-volume limitations of each alternative design is explored using eighteen geometric configurations and approximately three thousand volume scenarios, with the DLT design predicted to accommodate the highest demand volumes before failure is reached. Finally, six geometries are examined using both the planning-level tool and the validated microsimulation tool, finding that the curve of the capacity-to-delay relationship varies for each alternative design, invalidating the use of critical lane analysis as a comparative tool.
Ph. D.

Abstract:

La congestion du trafic dans nos villes est un problème qui entrave la qualité de vie. L'intersection est un endroit où les congestions se produisent le plus fréquemment. Par conséquent, au lieu d'étendre les infrastructures, il serait plus intéressant économiquement de s’ocupper de la résolution du problème des retards en développant les stratégies de contrôle de la circulation.Les travaux de cette thèse concerne l’étude des intersections dites « intelligentes » dépourvues de feux de signalisation, et où la coopération est réalisée à partir de la communication véhicule-infrastructure (V2I). L’objectif étant de proposer une modélisation coopérative de ces intersections visant à réduire à la fois les temps de retards et la consommation de carburant.La méthode de résolution du problème comporte deux volets principaux. Le premier volet concerne l'itinéraire devant être choisi par les véhicules pour arriver à leur destination à partir d’un point de départ. Le deuxième volet étant les procédures coopératives proposées afin de permettre aux véhicules de passer rapidement et économiquement à travers chaque intersection. D'une part, selon les informations envoyées en temps réel par les véhicules via la communication V2I à l’intérieur d’une zone de communication, chaque intersection exécute un algorithme soit de « Programmation Dynamique » soit de « Colonie d'Abeilles Artificielles » suivant la taille du trafic et ceci afin de donner aux véhicules l’ordre de passage minimisant le temps de retard dans les intersections. D'autre part, et après avoir reçu l’ordre de passage, chaque véhicule doit calculer son profil optimal de vitesse lui assurant une consommation minimale de carburant.Une série de simulations a ainsi été exécutée sous différents volumes de trafic afin de montrer la robustesse et la performance des méthodes proposées. Les résultats ont aussi été comparés avec d'autres méthodes de contrôle de la littérature et leur efficacité a ainsi été validée
The traffic congestion is one of the most serious problems limiting the improvement of standing of life. The intersection is a place where the jams occur the most frequently. Therefore, it is more effective and economical to relieve the problem of the heavy traffic delays by ameliorating the traffic control strategies, instead of extending the infrastructures.The proposed method is a cooperative modeling to solve the problem of reducing traffic delays and decreasing fuel consumption simultaneously in a network of intersections without traffic lights, where the cooperation is executed based on the connection of Vehicle-to-Infrastructure (V2I). The resolution contains two main steps. The first step concerns the itinerary. An itinerary presents a list of intersections chosen by vehicles to arrive at their destinations from their origins. The second step is related to the following proposed cooperative procedures to make vehicles to pass through each intersection rapidly and economically: on the one hand, according to the real-time information sent by vehicles in the edge of the communication zone via V2I, each intersection applies Dynamic Programming (DP) or Artificial Bee Colony (ABC) to cooperatively optimize the vehicle passing sequence in intersection with the minimal time delay under the relevant safety constraints; on the other hand, after receiving this sequence, each vehicle finds the optimal speed profiles with the minimal fuel consumption by an exhaustive search.A series of simulation are executed under different traffic volumes to present the performance of proposed method. The results are compared with other control methods and research papers to prove the our new traffic control strategy

Abstract:

The 2009 edition of the Manual on Uniform Traffic Control Devices (MUTCD) recommends a pedestrian walking speed of 3.5 feet per second for use in the timing of pedestrian clearance intervals at signalized intersections (reduced from 4.0 feet per second in the 2003 edition). Jurisdictions across the state of Utah continue to maintain pedestrian walking speeds of 4.0 feet per second for normal intersections with guidance on engineering judgement for areas where a lower pedestrian walking speed should be considered. In 2018, it was decided that the current state guidance with regard to pedestrian walking speeds be evaluated for any needed changes, such as adopting the national guidance found in the 2009 MUTCD. To evaluate pedestrian walking speeds at signalized intersections, 15 sites throughout the state of Utah were studied, producing a total of 2,061 observations of pedestrian crossing events. These crossing events were evaluated to calculate walking speeds in relation to pedestrian demographics at each location. Evaluated demographics included pedestrian group size, gender, mobility status, age category, alertness, and potential distractions. Upon completion of data collection, a statistical analysis was conducted to determine mean and 15th percentile pedestrian walking speeds by demographic. The data collection procedure, data analysis, and limited recommendations for pedestrian start-up delay and pedestrian walking speeds as used in signal timing are discussed in this report. The data suggest that Utah continue to maintain its guidance of 4.0 feet per second walking speeds at most signalized intersections, while exercising engineering judgment at locations containing high pedestrian volumes or locations containing high percentages of elderly or disabled pedestrians.

Abstract:

The dissertation studies traffic dispersion modeling in four parts. In the first part, the dissertation focuses on the Robertson platoon dispersion model which is the most widely used platoon dispersion model. The dissertation demonstrates the importance of the Yu and Van Aerde calibration procedure for the commonly accepted Robertson platoon dispersion model, which is implemented in the TRANSYT software. It demonstrates that the formulation results in an estimated downstream cyclic profile with a margin of error that increases as the size of the time step increases. In an attempt to address this shortcoming, the thesis proposes the use of three enhanced geometric distribution formulations that explicitly account for the time-step size within the modeling process. The proposed models are validated against field and simulated data.The second part focuses on implementation of the Robertson model inside the popular TRANSYT software. The dissertation first shows the importance of calibrating the recurrence platoon dispersion model. It is then demonstrated that the value of the travel time factor β is critical in estimating appropriate signal-timing plans. Alternatively, the dissertation demonstrates that the value of the platoon dispersion factor α does not significantly affect the estimated downstream cyclic flow profile; therefore, a unique value of α provides the necessary precision. Unfortunately, the TRANSYT software only allows the user to calibrate the platoon dispersion factor but does not allow the user to calibrate the travel time factor. In an attempt to address this shortcoming, the document proposes a formulation using the basic properties of the recurrence relationship to enable the user to control the travel time factor indirectly by altering the link average travel time.In the third part of the dissertation, a more general study of platoon dispersion models is presented. The main objective of this part is to evaluate the effect of the underlying travel time distribution on the accuracy and efficiency of platoon dispersion models, through qualitative and quantitative analyses. Since the data used in this study are generated by the INTEGRATION microsimulator, the document first describes the ability of INTEGRATION in generating realistic traffic dispersion effects. The dissertation then uses the microsimulator generated data to evaluate the prediction precision and performance of seven different platoon dispersion models, as well as the effect of different traffic control characteristics on the important efficiency measures used in traffic engineering. The results demonstrate that in terms of prediction accuracy the resulting flow profiles from all the models are very close, and only the geometric distribution of travel times gives higher fit error than others. It also indicates that for all the models the prediction accuracy declines as the travel distance increases, with the flow profiles approaching normality. In terms of efficiency, the travel time distribution has minimum effect on the offset selection and resulting delay. The study also demonstrates that the efficiency is affected more by the distance of travel than the travel time distribution.Finally, in the fourth part of the dissertation, platoon dispersion is studied from a microscopic standpoint. From this perspective traffic dispersion is modeled as differences in desired speed selection, or speed variability. The dissertation first investigates the corresponding steady-state behavior of the car-following models used in popular commercially available traffic microsimulation software and classifies them based on their steady-state characteristics in the uncongested regime. It is illustrated that with one exception, INTEGRATION which uses the Van Aerde car-following model, all the software assume that the desired speed in the uncongested regime is insensitive to traffic conditions. The document then addresses the effect of speed variability on the steady-state characteristics of the car-following models. It is shown that speed variability has significant influence on the speed-at-capacity and alters the behavior of the model in the uncongested regime. A method is proposed to effectively consider the influence of speed variability in the calibration process in order to control the steady-state behavior of the model. Finally, the effectiveness and validity of the proposed method is demonstrated through an example application.
Ph. D.

Abstract:

[Truncated abstract] In an urban network, any change to the capacity of a road or an intersection will generally result in some traffic changing its route. In addition the presence of intersections creates the need for frequent stops. These stops increase the fuel consumption by anywhere between thirty to fifty percent as evidenced by published standardised vehicle fuel consumption figures for urban and for country driving. Other components of vehicle operating costs such as tyre and brake wear and time costs will also be increased by varying amounts. Yet almost all methods in use for economic evaluation of urban road projects use open road vehicle operating costs (sometimes factored to represent an average allowance for stopping at intersections) for one year or sometimes two years in the analysis period and then make assumptions about how the year by year road user benefits may change throughout the period in order to complete the analysis. This thesis will describe a system for estimating road user costs in an urban network that calculates intersection effects separately and then adds these effects to the travel costs of moving between intersections. Daily traffic estimates are used with a distribution of the flow rate throughout the twenty-four hours giving variable speed of travel according to the level of congestion at different times of the day. For each link, estimates of traffic flow at two points in time are used to estimate the year-by-year traffic flow throughout the analysis period by linear interpolation or extrapolation. The annual road user costs are then calculated from these estimates. Annual road user benefits are obtained by subtracting the annual road user costs for a modified network from the annual road user costs for an unmodified network. The change in the road network maintenance costs are estimated by applying an annual per lane maintenance cost to the change in lane-kilometres of road in the two networks. The Benefit Cost Ratio is calculated for three discount rates. An estimate of the likely range of error in the Benefit Cost Ratio is also calculated

Abstract:

碩士
淡江大學
運輸管理學系運輸科學碩士班
106
Taiwan highway capacity manual mentioned roadway performance measurement is one of important index of level of service. There are three indexes for performance measurement　volume/capacity ratio, average delay time and average maximum queue length in cycle. Average delay time is most easy one to be calculated. But delay time calculation usually limited by data collection and device technology. We only can get some macroscopic information such as volume, speed and density. The delay model estimation used to build in macroscopic. However vehicle drive at signal intersection will impact by several factors. These factors will have major influence on vehicle delay. But there didn’t have much study on establish vehicle delay model in microscopic.In this study will use video record data divided by unit time to catch vehicle position. The position is used to coordinate axis conversion and build vehicle trajectory so as to get vehicle’s driving way. This method can actually track individual vehicle trajectory in unit time. Variable analysis to understand factors may impact vehicle delay. Establish individual vehicle delay model at signal intersection by regression model. The summation of all vehicle delay is the total delay of cycle. The total delay can compare to tradition delay model.

Abstract:

碩士
逢甲大學
交通工程與管理所
92
Advanced Traveler Information Systems (ATIS), one of the subsystems of Intelligent Transportation Systems (ITS), are designed to deliver information directly to travelers. Based on such information, travelers can make better decisions about route and departure time. One of the key issues of providing route guidance information is how to effectively generate reliable route information.When vehicles are traveling in the traffic network, the travel cost could be divided into two parts, link travel time and intersection delay. Most of the shortest path algorithms assume that there is no costs or prohibitions associated with intersection delays, but the intersection delays might be the dominant factor when calculating SP in a congested network. Thus, this research aims at developing one-to-all shortest path, K shortest path, and time-dependent shortest path algorithms with different cost considerations, such as intersection delays. These algorithms could reflect the dynamic characteristic of traffic and application to the environment of ITS in the future.Two methods of calculating intersection delays are (1) average delay under signal control and (2) average discharge delay. The delay under signal control could reflect the impact of signal and variations of flow, and the average discharge delay could reflect average discharge rate.In the research, the object-oriented approach is adopted to analyze and develop the system. According to the object-oriented analysis (OOA), this analysis could analyze the system demand and illustrate the system through different diagrams. The object-oriented approach provides two major functions: maintainability and reusability. Because of these two functions, it can reduce the programming time.Numerical experiments are conducted based on the Taichung city. In order to illustrate the system, several databases are constructed, such as network data, signal data, volume on links, number of vehicles crossing intersection, and velocity. Thus, the system can compute the travel time on links and time of delays which crossing intersection. Thus, the system can generate several different path databases that are in accordance with different intersection delays and algorithms. The numerical experiments indicate that the SP calculation with delay consideration could indeed capture the dynamic of flow variations in a realistic traffic network.

Abstract:

This dissertation analyzes two unsolved problems to fulfill the gap in the literature: (1). What is the vehicle delay and intersection capacity considering left-turn traffic at a pre-timed signal? (2). What are the mean and variance of delay to vehicles at a vehicle-actuated signal?The first part of this research evaluates the intersection performance in terms of capacity and delay at an isolated pre-timed signal intersection. Despite of a large body of literature on pre-timed signals, few work has examined the interactions be- tween left-turn and through vehicles. Usually a protected left-turn signal phase, before (leading) or after (lagging) through signal, is applied to a signalized inter- section when the traffic demand is relatively high. A common problem for leading left-turn operation is the blockage to left-turn vehicles by through traffic, particularly at an intersection with a short left-turn bay. During the peak hour, some vehicles on the through lane might not be able to depart at the end of a cycle, resulting in an increased probability of left-turn blockage. In turn, the blocked left-turn vehicles may also delay the through traffic to enter the intersection during the following cycle. Those problems may not exist for a lagging left-turn operation, since left-turn vehicles intend to spill out of the bay under heavy traffic. In this case, the through capacity is reduced, leading to an increase of total delay. All of these factors contribute to the difficulties of estimating the delay and capacity for an isolated intersection. In order to examine this missing part of study on the signalized intersection, two probabilistic models are proposed to deal with the left-turn bay blockage and queue spillback in a heuristic manner. Numerical case studies are also provided to test the proposed models. The second part of this research studies an isolated intersection with vehicle-actuated signal. Typically an advanced detector is located at a distance prior to the intersection such that an arriving vehicle triggers a green time extension in or- der to pass through without any stop. This extended time period actuated by the vehicle is called unit extension in this study. If no vehicle actuation occurs during a unit extension, the green phase would terminate in order to clear queues in other approaches. In this way, the actuated system dynamically allocates the green time among multiple approaches according to vehicle arrivals. And the unit extension is the only control parameter in this case. We develop a model to study the vehicle delay under a general arrival distribution with a given unit extension. Our model allows optimizing the intersection performance over the unit extension.The third part of this research applies graphical methods and diffusion approximations to the traffic signal problems. We reinterpret a graphical method which is originally proposed by Newell in order to directly measure the variance of the time for the queue clearance at a signalized intersection, which remains yet to be carefully examined in practice and would be rather challenging if only using the conventional queuing techniques. Our results demonstrate that graphical method explicitly presents both the deterministic and stochastic delay. We also illustrate that the theoretical background for the graphical methods in this particular application is inherently the diffusion approximation. Furthermore, we investigate the problems of disruptions occurred during a pre-timed traffic signal cycle. By diffusion approximation, we provide quantitative estimation on the duration that the effects of disruptions would dissipate.

Abstract:

碩士
逢甲大學
交通工程與管理所
98
Arterial systems play the critical role in urban traffic area, their operation performances could reflect the traffic movement conditions. The progression effects are the important index of positive measures along an arterial. We could introduce a model for maximum progressive intersections by the determination of offset to increase the progression performance of an arterial system. But the delay as a disutility measure is also a concern for road users. This paper aims to solve two different objectives along an arterial for both considerations of delay and progression. In the first stage, we get the coordinated cycle and individual split of each intersection. In the second stage, we get the optimal offset with the the model of maximum progressive intersections. For the validation process, we use a pseudo network to verify the operation performances under different scenarios. By the comparisons of the measures of effective (MOEs), we find the two stage model will perform better performances under some specified scenarios by the software of TSIS and Synchro. After this initial validation, we use the Wen-Shin arterial with six coordinated intersections in Taichung City as a field evaluation. The applied period is the morning peak hours in weekday. The field validation shows that the two stage model could decrease the MOEs of the percentages of stops and increase the travel speed with a little increasing of average delay by the comparisons of Synchro and current field timing plans.

Abstract:

碩士
國立中興大學
資訊科學與工程學系所
101
Under real traffic condition, the drivers may not be able to reach the destination very soon even if the drivers choose the shortest distance path. For example, the drivers will spend more travel time while distance path has traffic jam.There are many research papers regarding path planning in the literature. Some of them used the Ant Colony Optimization (ACO) Algorithm. Some of them considered intersection delay. However, none of them use ACO algorithm with intersection delay taken into consideration.Intersection delay is an important factor of travelling time in real world traffic. Igonoring intersection delay will result in inpraticle path planning. In this thesis, we propose a shortest-time path algorithm based on ant colony algorithm and intersection delay.For the experiments, we utilize the Highway Traffic Systems Simulation Model (HTSS model) of the Institute of Transportation for generating the traffic simulation data. The experimental results show that in a grid map, the proposed method could find the shortest-time path effectively from source to destination.

Abstract:

Traffic platoons created by traffic signals may have impacts on the operations ofdownstream intersections because they change the arrival pattern and gap distribution ofupstream traffic. There’s been a lot of research dealing with platoon effects onoperations at signalized intersections, while very limited research has been done for thatof unsignalized intersections.This research aims to develop a methodology for analyzing the platoon impactson major-street left-turn (MSLT) delay at two-way stop-controlled (TWSC)intersections. The main idea is using a microscopic simulation tool to simulate differentplatoon scenarios in opposing through traffic, then applying regression models to capturethe impacts of platoons on the delay of MSLT. Two platoon variables were adopted as asimplification of the complex platoon scenarios, making it practical to analyze theplatoon effects on MSLT delay.The first two steps were to build simulation models for real-world unsignalizedintersections and simulate scenarios with a combination of various factors related toplatoons in VISSIM simulation. Calibrations of these simulation models based on field data were performed before simulation started. The next step was to define, derive andcalibrate two platoon variables for describing the duration and intensity of platoonarrivals in the opposing through traffic, which effectively simplified the largecombination of various factors. At last, the two platoon variables and their relationshipwith MSLT delay change factor were modeled with regression tools. A relationshipbetween the two variables and the delay change factor was established, which indicateda positive effect by upstream platoons on MSLT delay and made it possible to quantifythe impacts. The findings in this research could also be used for future research on left turntreatment regarding platoon or signal impacts.

Abstract:

This project proposes two possible solutions for the phasing plan of the intersection near the City Hall of Leiria and presents the calculations of the cycle length and the intersection delay for both of them. The main goal of these solutions is to optimize the global functioning of the intersection. Since the number of cars that use an intersection is will fluctuate with time, when using pre-timed traffic lights, adjustments are needed to the settings of the traffic signals, to assure the accommodation of the present traffic flows in the intersection under acceptable conditions for drivers.

Abstract:

Die vorliegende Dissertationsschrift widmet sich zwei Zielen: Mittels Induktionsschleifen-Detektoren einerseits die Verkehrsregelung an Knotenpunkten durch die Minimierung von Fahrzeughalten zu verbessern, und andererseits eine Veränderung der Verkehrsqualität durch die Schätzung von Kfz-Wartezeiten automatisiert zu erheben.Im ersten Teil wird ein modellbasiertes Steuerverfahren entwickelt, das Grünzeiten verkehrsabhängig und lokal anpasst. Es kann sehr gut in eine übergeordnete Steuerung zur Koordinierung in Verkehrsnetzen eingebunden werden und überlässt dieser die Optimierung von Phasenfolgen, Umlauf- und Versatzzeiten.Um auch bei hohen Auslastungen Kapazitäten bestmöglich zu nutzen, priorisiert es zunächst die Leerung von Warteschlangen. Anschließend erfolgt die Anpassung der Grünzeiten zwischen einer minimalen und maximalen Dauer so, dass Fahrzeughalte minimiert werden. Dafür werden Detektoren in ausreichender Entfernung im Zufluss einer Kreuzung verwendet, um Fahrzeugankünfte an der Haltelinie für die aktuelle und die nächste Phase zu prognostizieren. Bei der sich anschließenden Bilanzierung potenzieller Fahrzeughalte und der Wahl des günstigsten Umschaltzeitpunktes kann auf zusätzliche Modellannahmen verzichtet werden. Die Simulationsergebnisse zeigen, dass bei einer Minimierung der Fahrzeughalte gleichzeitig eine Reduktion von Wartezeiten möglich ist.Im zweiten Teil werden Kfz-Wartezeiten auf Basis der meist bereits vorhandenen Induktionsschleifen-Detektoren im Zufluss und im Abfluss einer Kreuzung geschätzt. Dafür werden die Zeitpunkte der Fahrzeugüberfahrten an einem Zufluss- und einem Abflussquerschnitt getrennt gemessen werden. Aus ihnen wird jeweils ein mittlerer Überfahrzeitpunkt ermittelt und nach Berücksichtigung der freien Fahrzeit eine mittlere Wartezeit geschätzt. Messintervalle an beiden Querschnitten, die um die mittlere freie Fahrzeit versetzt sind, sowie eine unbedingte Warteschlangenleerung am Ende einer Messung sollen sicherstellen, dass potenziell dieselben Fahrzeuge erfasst werden. Auf eine Fahrzeugwiedererkennung und damit auf eine Ausrüstung mit zusätzlicher Technik kann dadurch verzichtet werden.Damit sich das Verfahren für den Praxiseinsatz eignet, muss es möglichst robust gegenüber zufälligen Detektorfehlern sein. Dafür wird ein Fehlermodell entwickelt und mögliche Abweichungen gegenüber einer korrekten Messung untersucht. Aufgrund der unabhängigen Berechnung von mittleren Überfahrzeiten aus der getrennten Messung im Zufluss und im Abfluss zeigt sich, dass zufällige Fehler nicht zu systematischen Abweichungen in der Wartezeitschätzung führen.

Abstract:

The travel times of public transit systems that operate on mixed use right-of-ways are often dictated by the delays experienced at signalized intersections. When these delays become large and/or highly variable, transit quality degrades and agency operating costs increase. A number of transit priority measures can be applied, including transit signal priority or queue jump lanes. However, it is necessary that a process of prioritizing intersections for priority treatment be conducted so as to ensure the greatest return on investment is achieved. This thesis proposes and demonstrates a methodology to determine the distribution of stopped delays experienced by transit vehicles at signalized intersections using archived AVL (automated vehicle location) and APC (automated passenger counting) data. This methodology is calibrated and validated using queue length and bus unscheduled stopped delay data measured at a field site. Results show the proposed methodology is of sufficient accuracy to be used in practice for prioritizing signalized intersections for priority treatment. On the condition that a sample of the transit vehicle fleet is equipped with an AVL/APC system, the proposed methodology can be automatically implemented using the archived AVL/APC data and therefore avoid the need to conduct dedicated data collection surveys. The proposed methodology can provide estimates of (1) the maximum extent of the queue; and (2) measures of the distribution of stopped delays experienced by transit vehicles (e.g. mean, standard deviation, 90th percentile, etc.) caused by the downstream traffic signal. These measures can be produced separately for different analysis periods (e.g. different times of the day; days of the week; and time of the year) and can be compiled separately for different transit routes. These outputs can then be used to identify and prioritize signalized intersections as candidates for transit signal priority measures.The proposed method is suitable for application to most transit AVL/APC databases and is demonstrated using data from Grand River Transit, the public transit service provider in the Region of Waterloo, Ontario Canada.

Abstract:

Up until recently, unsignalized nodes have been either ignored or inadequately represented in Dynamic Traffic Assignment (DTA) models. This is due to the difficult nature of incorporating internal node conflicts into dynamic flow models. It was thought or assumed that these nodes had little impact on overall model results, but evidence from testing in Visual Interactive System for Transportation Algorithms (VISTA), a DTA model, reveals that may not be the case. This paper explores recent attempts at characterizing stop sign effects within DTA flow models. From previous studies, it has been found that incorporating these unsignalized and priority movements internal to the flow model requires large amounts of computational power, are challenging to make efficient, and lead to a multiple or infinite solution space. Based on these findings, a deterministic approach is both impractical and likely impossible in the existing framework of the Cell Transmission (CTM) and Link Transmission (LTM) models commonly used in DTA. Thus, a method of utilizing empirical relationships based on information readily available in these models may be a more acceptable approach. Microsimulation is much more suitable for modeling these types of interactions and is capable of producing results near to reality. For this reason, microsimulation was chosen as a viable method for developing empirical relationships of such complex interactions to then be used as inputs into the macroscopic flow models of DTA. This paper presents a model developed to calculate delays expected by vehicles at stop approaches based on information that can be taken from a dynamic flow model such as CTM and LTM models. This model is validated by video data recorded and analyzed for accuracy. Potential uses and probable implementations of the model are explored to appropriately incorporate unsignalized and priority movements into existing flow models.
text

Abstract:

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2008.
Source: Dissertation Abstracts International, Volume: 69-11, Section: B, page: 7009. Adviser: Rahim Benekohal. Includes bibliographical references (leaves 148-151) Available on microfilm from Pro Quest Information and Learning.

Abstract:

碩士
國立交通大學
運輸科技與管理學系
93
Signalized intersections are the locations that convert each approaching traffic stream into merging, diverging, and intersecting movements. Such locations will become the bottlenecks that may further degrade the traffic system due to dense demand and/or worse signal installation. Delays have been long term known as one of the most important indices in evaluating intersection control performance, for instance, the level of service and/or signal timing design. It is seen that most of the past research had widely applied the stopped delay as a basis to estimate some others such as approach delays. Unfortunately, this may sometimes lead to a higher estimation error. With the above consideration, this study is intended to explore and measure the other term, time-in-queue delay, for intersections using the graphic method supported by field data. Because most of the delay models were developed based on stopped delays and the traffic characteristics may vary greatly between countries, directly citing the existing models, approaches, or specific research results for delays may greatly deviate the true value in our country. Thus, this study first analyzed some key elements of delay time with which the analytical delay model could be formulated. Secondly, the location of each vehicle entering and leaving the signal at each time slice during the study period was traced and recorded. The trajectories of all individual vehicles were then plotted to verify the model validity. Finally, the analytical model was directly used to estimate various delay values for evaluating service quality and traffic control alternatives at intersections. Based on the analytical model, a simulation program was developed in JAVA in order to generate successive vehicle arrivals and record their corresponding trajectories when approaching the signal. With the data recorded, the stopped delay, approach delay, and time-in-queue delay to individual vehicles could be estimated separately. The simulation results showed that the three estimated delays were fairly close to those collected at sites. A series of sensitivity tests also showed that the time-in-queue delays are larger than the other two. In addition, this study also discussed the drawbacks of using time-in-queue delay when special conditions such as long distance travel approaches, extremely small deceleration rate, and high approaching speeds occur.