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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Design Strategies for an Artificial Neural Network Based Algorithm for Automatic Incident Detection on Major Arterial Streets

Zhu, Xuesong 11 March 2008 (has links)
Traffic incidents are non-recurring events that can cause a temporary reduction in roadway capacity. They have been recognized as a major contributor to traffic congestion on our national highway systems. To alleviate their impacts on capacity, automatic incident detection (AID) has been applied as an incident management strategy to reduce the total incident duration. AID relies on an algorithm to identify the occurrence of incidents by analyzing real-time traffic data collected from surveillance detectors. Significant research has been performed to develop AID algorithms for incident detection on freeways; however, similar research on major arterial streets remains largely at the initial stage of development and testing. This dissertation research aims to identify design strategies for the deployment of an Artificial Neural Network (ANN) based AID algorithm for major arterial streets. A section of the US-1 corridor in Miami-Dade County, Florida was coded in the CORSIM microscopic simulation model to generate data for both model calibration and validation. To better capture the relationship between the traffic data and the corresponding incident status, Discrete Wavelet Transform (DWT) and data normalization were applied to the simulated data. Multiple ANN models were then developed for different detector configurations, historical data usage, and the selection of traffic flow parameters. To assess the performance of different design alternatives, the model outputs were compared based on both detection rate (DR) and false alarm rate (FAR). The results show that the best models were able to achieve a high DR of between 90% and 95%, a mean time to detect (MTTD) of 55-85 seconds, and a FAR below 4%. The results also show that a detector configuration including only the mid-block and upstream detectors performs almost as well as one that also includes a downstream detector. In addition, DWT was found to be able to improve model performance, and the use of historical data from previous time cycles improved the detection rate. Speed was found to have the most significant impact on the detection rate, while volume was found to contribute the least. The results from this research provide useful insights on the design of AID for arterial street applications.
2

Analysis of Freeway Weaving Areas Using Corridor Simulator and Highway Capacity Manual

Ramachandran, Suresh 11 December 1997 (has links)
Weaving is defined as the crossing of two or more traffic streams traveling in the same direction along a significant length of the highway without the aid of traffic control devices . The traditional methods used for design and operational analysis of a highway is the Highway Capacity Manual (HCM). The traditional weaving methods in the highway capacity manual use road geometry and traffic volume as inputs and provide an estimate of speed as an output. CORSIM is a new computer simulation model developed by Federal Highway Administration (FHWA) for simulation of traffic behavior on integrated urban transportation networks of freeway and surface streets. The intent of this research is to identify the difference in the results by using the new CORSIM simulation and the traditional HCM approach in modeling the weaving sections on a freeway and make recommendations. The research will also compare the modeling strategy and provide analysis of the output. / Master of Science
3

A Comparative Analysis of Weaving Areas in HCM, TRANSIMS, CORSIM, VISSIM and INTEGRATION

Koppula, Nanditha 29 May 2002 (has links)
Traffic simulation is a powerful tool that provides transportation engineers with the ability to test the feasibility and performance of a system before it is implemented and also helps in optimizing the proposed system. Over the past twenty years significant amount of work has been conducted on improving the quality and accuracy of transportation simulation models. Much of this work has been concentrated on microscopic simulation models because they provide traffic engineers greater opportunity to examine the inherently complex, stochastic, and dynamic nature of transportation systems when compared to traditional macroscopic models. In order to test the performance of some of the simulation models, a study is conducted on freeway weaving sections, which are considered to be one of the most complex regions to be modeled and analyzed. The intent of the research is to evaluate TRANSIMS, CORSIM, VISSIM and INTEGRATION and compare them with Highway Capacity Manual, which adopts a traditional methodology for carrying out the operational analysis of a highway system. The statistics collected for the simulation runs include weaving speeds, non-weaving speeds and density of the weaving section. / Master of Science
4

Investigações no campo da programação semafórica / Research on the signal programming field

Fornaciari, Isabela Aparecida 29 October 2010 (has links)
Neste trabalho são investigados alguns aspectos relacionados com a programação de tempos de semáforos isolados. A seguir são comentados os principais resultados obtidos. Os valores obtidos na cidade de São Carlos são os seguintes: tempo médio total (no início e no final) perdido no verde mais amarelo por fase veicular nos semáforos igual a 3,12 s (interseção em nível e fluxo sem conversão); velocidade média dos pedestres na travessia em semáforos igual a 1,28 m/s e velocidade correspondente ao 85 percentil igual a 1,00 m/s. Com exceção de alguns casos especiais, os valores do atraso fornecidos pelos métodos: Webster, HCM-2000, Simulador Integration e Simulador Corsim são da mesma magnitude e, portanto, perfeitamente viáveis de serem utilizados nos estudos práticos. Na determinação dos tempos que compõem a fase destinada à travessia de pedestres em semáforos, os métodos Ferraz e MUTCD são mais indicados que os métodos Webster/Denatran e CET-SP, uma vez que proporcionam adequada segurança sem \"assustar\" os pedestres e com o mínimo de prejuízo à capacidade do fluxo veicular. O emprego de fase exclusiva para pedestres em semáforos com duas fases veiculares leva aos seguintes acréscimos aproximados nos valores do atraso médio dos veículos: 40% para fluxos veiculares até 1000 v/h, 25% para fluxos veiculares da ordem de 1100 v/h e 20% para fluxos veiculares da ordem de 1200 v/h. / In this research some aspects related to time programming of single traffic lights are investigated. The main results are commented as follows. The values obtained in the city of São Carlos are: total average lost time (in the beginning and in the end) in the green and yellow phases in each vehicular signal phase equal to 3.12 s (level intersection and flow without conversion), pedestrians average speed on the traffic lights crossing equal to 1.28 m/s and speed corresponding to the 85º percentile equal to 1.00 m/s. Except for some special cases, the values of the delay provided by the Webster, HCM-2000, Simulator Integration and Simulator Corsim methods are of the same magnitude and, therefore, they are perfectly feasible to use in practical studies. In determining the periods of the pedestrian crossing stage for the traffic signals, the Ferraz and MUTCD methods are more indicated than the Webster/Denatran and CET-SP methods, since they provide appropriate safety without \"scaring\" the pedestrians and with minimal damage to the vehicular flow capacity. The use of exclusive pedestrian phase at two vehicular stage signals leads to the following approximate increases in the values of the vehicles average delay: 40% to vehicle flow up to 1000 v/h, 25% for vehicle flow about 1100 v/h, and 20% for vehicle flow about 1200 v/h. In this research some aspects related to time programming of single traffic lights are investigated.
5

Investigações no campo da programação semafórica / Research on the signal programming field

Isabela Aparecida Fornaciari 29 October 2010 (has links)
Neste trabalho são investigados alguns aspectos relacionados com a programação de tempos de semáforos isolados. A seguir são comentados os principais resultados obtidos. Os valores obtidos na cidade de São Carlos são os seguintes: tempo médio total (no início e no final) perdido no verde mais amarelo por fase veicular nos semáforos igual a 3,12 s (interseção em nível e fluxo sem conversão); velocidade média dos pedestres na travessia em semáforos igual a 1,28 m/s e velocidade correspondente ao 85 percentil igual a 1,00 m/s. Com exceção de alguns casos especiais, os valores do atraso fornecidos pelos métodos: Webster, HCM-2000, Simulador Integration e Simulador Corsim são da mesma magnitude e, portanto, perfeitamente viáveis de serem utilizados nos estudos práticos. Na determinação dos tempos que compõem a fase destinada à travessia de pedestres em semáforos, os métodos Ferraz e MUTCD são mais indicados que os métodos Webster/Denatran e CET-SP, uma vez que proporcionam adequada segurança sem \"assustar\" os pedestres e com o mínimo de prejuízo à capacidade do fluxo veicular. O emprego de fase exclusiva para pedestres em semáforos com duas fases veiculares leva aos seguintes acréscimos aproximados nos valores do atraso médio dos veículos: 40% para fluxos veiculares até 1000 v/h, 25% para fluxos veiculares da ordem de 1100 v/h e 20% para fluxos veiculares da ordem de 1200 v/h. / In this research some aspects related to time programming of single traffic lights are investigated. The main results are commented as follows. The values obtained in the city of São Carlos are: total average lost time (in the beginning and in the end) in the green and yellow phases in each vehicular signal phase equal to 3.12 s (level intersection and flow without conversion), pedestrians average speed on the traffic lights crossing equal to 1.28 m/s and speed corresponding to the 85º percentile equal to 1.00 m/s. Except for some special cases, the values of the delay provided by the Webster, HCM-2000, Simulator Integration and Simulator Corsim methods are of the same magnitude and, therefore, they are perfectly feasible to use in practical studies. In determining the periods of the pedestrian crossing stage for the traffic signals, the Ferraz and MUTCD methods are more indicated than the Webster/Denatran and CET-SP methods, since they provide appropriate safety without \"scaring\" the pedestrians and with minimal damage to the vehicular flow capacity. The use of exclusive pedestrian phase at two vehicular stage signals leads to the following approximate increases in the values of the vehicles average delay: 40% to vehicle flow up to 1000 v/h, 25% for vehicle flow about 1100 v/h, and 20% for vehicle flow about 1200 v/h. In this research some aspects related to time programming of single traffic lights are investigated.
6

Freeway Exit Ramp Traffic Flow Research Based on Computer Simulation

Wang, Xu 07 December 2007 (has links)
Interstate highways are one of the most important components of the transportation infrastructure in America. Freeway ramps play an important role in the whole interstate transportation system. This paper researches the traffic flow characteristics of four typical exit ramps in USA, which are tapered one-lane exit, tapered two-lane exit, parallel one-lane exit and parallel two-lane exit. Computer simulation software, such as CORSIM and HCS are applied as the main tools in this research. ANOVA and Tukey are used for statistical purpose. It compares the maximum capacity, average running speed and the total lane change number of those four exit ramps. It is found that no matter in terms of traffic discharging rate or total lane charging number; the tapered two-lane exit has the best operational performance. Tapered one-lane exit ramp has the least capacity. Parallel one-lane exit and parallel two-lane exit have very limited traffic operational difference in terms of capacity and running speed. It is recommended that parallel two-lane exit ramp should not be designed along the freeway if the right of way along arterial road is enough. It is observed from the simulation data that the grade of freeway, truck percentage, restricted to the truck use of certain lane(s) and the location of exit sign have significant impact on the running speed and total lane change number. An uphill can decrease the running speed dramatically while more truck brings more lane change, causing safety concerns. It is found that when trucks are restricted to the right two most lane, there will be less lane change number comparing with trucks are not restricted. Location of exit sign operates well at the distance between 4000 ft to 5000 ft. does have a significant impact on the operational speed and total lane change number before, within or after functional area of an exit, based on the data analysis of simulation runs.
7

Eliminating Right-Turn-on-Red (RTOR) at Key Intersections in a City Core : A Traffic Simulation Study Analyzing How Traffic Conditions Could Change When Restricting RTOR in Downtown Fredericton, New Brunswick

Aspnäs, Frida January 2012 (has links)
The City of Fredericton is the capital of New Brunswick, located in eastern Canada. Right-turn-on-red (RTOR) is a general practice at any traffic intersection in this maritime province. Many collisions between pedestrians and vehicles have been recorded at signalized intersections in the downtown area of the city. Due to the number of collisions, the City of Fredericton was interested in investigating how a restriction against RTOR could affect vehicular traffic. The purpose and goal of this project was to develop a calibrated traffic model of the downtown area of Fredericton that could be used for simulation studies. Two main changes were investigated: 1) a restriction against RTOR for each of eleven key intersections in the downtown area, and 2) a restriction against left-turns at one selected intersection. The traffic simulation model was also used for analyzing how factors such as pedestrian volumes, lane channelization, and turning proportions affect the changes in traffic conditions due to permitting, or prohibiting, right-turn-on-red. The traffic simulation model was created in the TSIS/CORSIM software. Several different scenarios were generated for analysis. The results of the simulation show that the traffic conditions in the whole downtown area will be affected when introducing a restriction against RTOR. Certain intersections show a relatively high change while others show no significant change at all. Several different factors were seen to affect the number of RTOR that could be performed at an intersection. One main factor was lane channelization. With a shared lane, the proportion of right-turning vehicles at the intersection was found to highly affect how many RTOR can be performed. Pedestrian volumes prove to be a third factor affecting the number of RTOR at an intersection. Overall results demonstrate that there are only a few intersections where it is suitable for the City of Fredericton to implement a restriction against RTOR.
8

Evaluation of Traffic Simulation Models for Work Zones in the New England Area

Khanta, Pothu Raju 01 January 2008 (has links) (PDF)
There are many traffic simulation modeling packages in existence, some of which are designed specifically for work zone analysis. These packages include, for example QUEWZ, Quick Zone, CORSIM and VISSIM. This research evaluates the capabilities of these simulation packages to determine whether or not these packages produce reasonable impact estimates. The research concludes with a set of recommendations to assist transportation professionals in selecting the most appropriate simulation package for a particular work zone project.
9

Integrating a Regional Planning Model (TRANSIMS) With an Operational Model (CORSIM)

Gu, Yahong 25 February 2004 (has links)
TRANSIMS is a disaggregate, behavioral, regional transportation planning package developed by Los Alamos National Laboratory (LANL) under funding from US DOT, EPA, and Department of Energy. It is an integrated system of travel forecasting models designed to give transportation planners accurate, complete information on traffic impacts, congestion, and pollution by simulating on a second-by-second basis the movements of every person and every vehicle through the transportation network of a large metropolitan area. This regional microsimulation approach provides a better assessment of the performance of a large network than the current link performance functions utilized in the current planning procedures. On the other hand, their microsimulation approach on a regional scale requires a lot of data that may not be readily available, and utilize a low fidelity microsimulation in order to make it operational. Some agencies may be interested in performing a more detailed investigation of traffic patterns within a sub area, such as the downtown area. The author implemented a subarea focusing methodology within TRANSIMS and also developed an interface that allows the investigator to use a high-fidelity, small-size network efficient traffic operational software package — CORSIM to perform sub area traffic operational analysis with demand and network extracted from applications of TRANSIMS. This methodology will allow TRANSIMS to take advantage of higher fidelity models for sub-network analysis and allow CORSIM to use planning inputs such as individual 24 hour travel activities and trip chains. An evacuation model is also built and applied to Virginia Tech main campus, Blacksburg, VA to evaluate this sub area focusing methodology. / Master of Science
10

THE INTERACTIVE HARDWARE-IN-LOOP SIMULATION SYSTEM FOR TRAFFIC CONTROL SYSTEM DEVELOPMENT

Sheng, Li January 2005 (has links)
No description available.

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