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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

Crossing locations, light conditions, and pedestrian injury severity

Siddiqui, Naved Alam 01 June 2006 (has links)
This study assesses the role of crossing locations and light conditions in pedestrian injury severity through a multivariate regression analysis to control for many other factors that also may influence pedestrian injury severity. Crossing locations include midblock and intersections, and light conditions include daylight, dark with street lighting, and dark without street lighting. The study formulates a theoretical framework on the determinants of pedestrian injury severity, and specifies an empirical model accordingly. An ordered probit model is then applied to the KABCO severity scale of pedestrian injuries which occurred while attempting street crossing in the years 1986 to 2003 in Florida. In terms of crossing locations, the probability of a pedestrian dying when struck by a vehicle, is higher at midblock locations than at intersections for any light condition. In fact, the odds of sustaining a fatal injury is 49 percent lower at intersections than at midblock locations under daylight conditions, 24 percent lower under dark with street lighting conditions, and 5 percent lower under dark without street lighting conditions. Relative to dark conditions without street lighting, daylight reduces the odds of a fatal injury by 75 percent at midblock locations and by 83 percent at intersections, while street lighting reduces the odds by 42 percent at midblock locations and by 54 percent at intersections.
2

Método para avaliar o risco potencial de atropelamentos em travessias urbanas em meio de quadra

Diógenes, Mara Chagas January 2008 (has links)
A alta ocorrência de atropelamentos nas áreas urbanas acarreta altos custos econômicos e sociais. Por isso, é importante a adoção de medidas de segurança viária que visem previnir e mitigar os riscos de acidentes envolvendo pedestres. Para que essas medidas sejam eficazes, sua escolha deve estar embasada em informações sobre onde, como e porque os atropelamentos acontecem. Uma forma de obtenção dessas informações envolve as avaliações de risco. Este trabalho propõe um método de avaliação de risco potencial de atropelamentos em travessias urbanas em meio de quadra. O método proposto incorpora análises quantitativas e qualitativas através de técnicas de modelagem que relacionam a incidência de atropelamentos e a percepção de risco dos pedestres com os fatores de risco. A aplicação do método envolveu a análise dos dados de atropelamentos registrados na cidade de Porto Alegre durante o período de 1998 e 2006 e a identificação das travessias em meio de quadra onde ocorreu o maior número de atropelamentos nesse período. Foram identificadas e, então, analisadas 21 travessias em meio de quadra. A análise das travessias incluiu a coleta de dados referentes aos fatores de risco e uma simulação de vídeo, onde pedestres e especialistas avaliaram as travessias no que concerne a sua segurança. A partir dos dados coletados, foram construídos dois modelos de regressão, um embasado em dados de ocorrência de atropelamentos e outro em dados de percepção de risco. A análise desses modelos mostrou que o risco de atropelamento é influenciado por uma combinação de fatores de risco, entre os quais as características do transporte coletivo, a largura da via, o número de faixas de tráfego de veículos, o volume de pedestres e de veículos. Ressalta-se que os modelos construídos podem ser utilizados para relativizar o risco observado e percebido de travessias em meio de quadra de Porto Alegre e fornecer indicativos para o gerenciamento da segurança dos pedestres. O estudo de caso mostrou que a aplicação do método proposto é simples, sendo possível a sua transferência a realidades onde há escassez de dados e recursos para sua obtenção. / The high occurrence of pedestrian crashes in urban areas results in high social and economic costs. To address this problem, it is important to adopt countermeasures that aim to prevent and reduce the risk of pedestrian crash. In order to obtain efficient countermeasures, their selection must be based on information of where, when and why the pedestrian crashes occur. This information can be obtained through risk evaluation. This dissertation proposes a method to evaluate the potential risk of pedestrian crash at midblock crosswalks. The proposed method incorporates quantitative and qualitative analyses, using modeling techniques to understand the relationship of risk factors with pedestrian crash occurrence and the relationship of risk factors with pedestrian risk perception. The method application comprised the analysis of reported pedestrian crashes in the city of Porto Alegre, in southern Brazil, over the period of 1998 to 2006 and the identification of midblock crosswalks with the highest incidence of pedestrian crash. Twenty one midblock crosswalks were indentified and, then analyzed. The crosswalks’ analysis included data collection about risk factors and video simulations. During the video simulations, pedestrians and experts evaluated the crosswalks’ safety. Two regression models were developed using the data collected, one based on pedestrian crash occurrence and one based on risk perception data. The analysis of models showed that pedestrian crash risk is influenced by a combination of risk factors, such as public transportation characteristics, road width, number of through lanes, pedestrian and vehicle volumes. The developed models can be used to relativize the observed and perceived risk of midblock crosswalks in Porto Alegre and to provide information to the pedestrian safety management. The case study results showed that the application of the proposed method is simple and it is possible to use it on real world cases where data and resources to obtain such data are scarce.
3

Método para avaliar o risco potencial de atropelamentos em travessias urbanas em meio de quadra

Diógenes, Mara Chagas January 2008 (has links)
A alta ocorrência de atropelamentos nas áreas urbanas acarreta altos custos econômicos e sociais. Por isso, é importante a adoção de medidas de segurança viária que visem previnir e mitigar os riscos de acidentes envolvendo pedestres. Para que essas medidas sejam eficazes, sua escolha deve estar embasada em informações sobre onde, como e porque os atropelamentos acontecem. Uma forma de obtenção dessas informações envolve as avaliações de risco. Este trabalho propõe um método de avaliação de risco potencial de atropelamentos em travessias urbanas em meio de quadra. O método proposto incorpora análises quantitativas e qualitativas através de técnicas de modelagem que relacionam a incidência de atropelamentos e a percepção de risco dos pedestres com os fatores de risco. A aplicação do método envolveu a análise dos dados de atropelamentos registrados na cidade de Porto Alegre durante o período de 1998 e 2006 e a identificação das travessias em meio de quadra onde ocorreu o maior número de atropelamentos nesse período. Foram identificadas e, então, analisadas 21 travessias em meio de quadra. A análise das travessias incluiu a coleta de dados referentes aos fatores de risco e uma simulação de vídeo, onde pedestres e especialistas avaliaram as travessias no que concerne a sua segurança. A partir dos dados coletados, foram construídos dois modelos de regressão, um embasado em dados de ocorrência de atropelamentos e outro em dados de percepção de risco. A análise desses modelos mostrou que o risco de atropelamento é influenciado por uma combinação de fatores de risco, entre os quais as características do transporte coletivo, a largura da via, o número de faixas de tráfego de veículos, o volume de pedestres e de veículos. Ressalta-se que os modelos construídos podem ser utilizados para relativizar o risco observado e percebido de travessias em meio de quadra de Porto Alegre e fornecer indicativos para o gerenciamento da segurança dos pedestres. O estudo de caso mostrou que a aplicação do método proposto é simples, sendo possível a sua transferência a realidades onde há escassez de dados e recursos para sua obtenção. / The high occurrence of pedestrian crashes in urban areas results in high social and economic costs. To address this problem, it is important to adopt countermeasures that aim to prevent and reduce the risk of pedestrian crash. In order to obtain efficient countermeasures, their selection must be based on information of where, when and why the pedestrian crashes occur. This information can be obtained through risk evaluation. This dissertation proposes a method to evaluate the potential risk of pedestrian crash at midblock crosswalks. The proposed method incorporates quantitative and qualitative analyses, using modeling techniques to understand the relationship of risk factors with pedestrian crash occurrence and the relationship of risk factors with pedestrian risk perception. The method application comprised the analysis of reported pedestrian crashes in the city of Porto Alegre, in southern Brazil, over the period of 1998 to 2006 and the identification of midblock crosswalks with the highest incidence of pedestrian crash. Twenty one midblock crosswalks were indentified and, then analyzed. The crosswalks’ analysis included data collection about risk factors and video simulations. During the video simulations, pedestrians and experts evaluated the crosswalks’ safety. Two regression models were developed using the data collected, one based on pedestrian crash occurrence and one based on risk perception data. The analysis of models showed that pedestrian crash risk is influenced by a combination of risk factors, such as public transportation characteristics, road width, number of through lanes, pedestrian and vehicle volumes. The developed models can be used to relativize the observed and perceived risk of midblock crosswalks in Porto Alegre and to provide information to the pedestrian safety management. The case study results showed that the application of the proposed method is simple and it is possible to use it on real world cases where data and resources to obtain such data are scarce.
4

Método para avaliar o risco potencial de atropelamentos em travessias urbanas em meio de quadra

Diógenes, Mara Chagas January 2008 (has links)
A alta ocorrência de atropelamentos nas áreas urbanas acarreta altos custos econômicos e sociais. Por isso, é importante a adoção de medidas de segurança viária que visem previnir e mitigar os riscos de acidentes envolvendo pedestres. Para que essas medidas sejam eficazes, sua escolha deve estar embasada em informações sobre onde, como e porque os atropelamentos acontecem. Uma forma de obtenção dessas informações envolve as avaliações de risco. Este trabalho propõe um método de avaliação de risco potencial de atropelamentos em travessias urbanas em meio de quadra. O método proposto incorpora análises quantitativas e qualitativas através de técnicas de modelagem que relacionam a incidência de atropelamentos e a percepção de risco dos pedestres com os fatores de risco. A aplicação do método envolveu a análise dos dados de atropelamentos registrados na cidade de Porto Alegre durante o período de 1998 e 2006 e a identificação das travessias em meio de quadra onde ocorreu o maior número de atropelamentos nesse período. Foram identificadas e, então, analisadas 21 travessias em meio de quadra. A análise das travessias incluiu a coleta de dados referentes aos fatores de risco e uma simulação de vídeo, onde pedestres e especialistas avaliaram as travessias no que concerne a sua segurança. A partir dos dados coletados, foram construídos dois modelos de regressão, um embasado em dados de ocorrência de atropelamentos e outro em dados de percepção de risco. A análise desses modelos mostrou que o risco de atropelamento é influenciado por uma combinação de fatores de risco, entre os quais as características do transporte coletivo, a largura da via, o número de faixas de tráfego de veículos, o volume de pedestres e de veículos. Ressalta-se que os modelos construídos podem ser utilizados para relativizar o risco observado e percebido de travessias em meio de quadra de Porto Alegre e fornecer indicativos para o gerenciamento da segurança dos pedestres. O estudo de caso mostrou que a aplicação do método proposto é simples, sendo possível a sua transferência a realidades onde há escassez de dados e recursos para sua obtenção. / The high occurrence of pedestrian crashes in urban areas results in high social and economic costs. To address this problem, it is important to adopt countermeasures that aim to prevent and reduce the risk of pedestrian crash. In order to obtain efficient countermeasures, their selection must be based on information of where, when and why the pedestrian crashes occur. This information can be obtained through risk evaluation. This dissertation proposes a method to evaluate the potential risk of pedestrian crash at midblock crosswalks. The proposed method incorporates quantitative and qualitative analyses, using modeling techniques to understand the relationship of risk factors with pedestrian crash occurrence and the relationship of risk factors with pedestrian risk perception. The method application comprised the analysis of reported pedestrian crashes in the city of Porto Alegre, in southern Brazil, over the period of 1998 to 2006 and the identification of midblock crosswalks with the highest incidence of pedestrian crash. Twenty one midblock crosswalks were indentified and, then analyzed. The crosswalks’ analysis included data collection about risk factors and video simulations. During the video simulations, pedestrians and experts evaluated the crosswalks’ safety. Two regression models were developed using the data collected, one based on pedestrian crash occurrence and one based on risk perception data. The analysis of models showed that pedestrian crash risk is influenced by a combination of risk factors, such as public transportation characteristics, road width, number of through lanes, pedestrian and vehicle volumes. The developed models can be used to relativize the observed and perceived risk of midblock crosswalks in Porto Alegre and to provide information to the pedestrian safety management. The case study results showed that the application of the proposed method is simple and it is possible to use it on real world cases where data and resources to obtain such data are scarce.
5

Evaluation of PC-Based Virtual Reality as a Tool to Analyze Pedestrian Behavior at Midblock Crossings

Mai, Kristina Lynn 01 June 2017 (has links) (PDF)
The aim of this research was to analyze if current generation PC-driven virtual reality simulations can be used to accurately mimic and therefore, observe behavior at a crosswalk. Toward that goal, the following research tasks were carried out: a) Designing a 3D virtual crosswalk and recruiting volunteers to wear the HTC Vive headset and to walk across the street, b) Setting up cameras near the midblock crosswalk on University Drive at California Polytechnic State University, San Luis Obispo to observe pedestrians, and c) Comparing pedestrian behavior data from both the virtual and real midblock crosswalk. The comparison was based on the following criteria: a) Pedestrian walking speed, b) Observation patterns prior to crossing the road, characterized by glancing left and right to detect cars, and c) Pedestrians’ decisions as to where to cross, defined by if they chose to walk directly on or outside of the midblock crosswalk. Walking speed and the number of pedestrians who looked left and right before crossing were significantly different in both the virtual and real environments. On the other hand, the proportion of people who chose to walk on the crosswalk was similar in both environments. This result indicates that there is a future potential in using virtual reality to analyze pedestrian behavior at roundabouts. Although this study showed that PC-driven virtual reality is not effective in replicating pedestrian walking speeds or pedestrian observation patterns at a midblock crosswalk, researchers may expect PC-driven virtual reality to have greater applications within the transportation discipline once the technology improves over the years. Potential improvements in technology that would help include being wireless, allowing users to walk in a non-confining space, and making the equipment more affordable, allowing the technology to become more mainstream.
6

Assessment of Midblock Pedestrian Crossing Facilities using Surrogate Safety Measures and Vehicle Delay

Anwari, Nafis 01 January 2023 (has links) (PDF)
This dissertation has contributed to the pedestrian safety literature by assessing and comparing safety benefits and traffic efficiency among midblock Rectangular Rapid Flashing Beacon (RRFB) and Pedestrian Hybrid Beacon (PHB) sites. Video trajectory data were used to calculate pedestrian Surrogate Safety Measures (SSMs) and vehicles' delay. Regression models of SSMs and vehicles' delay revealed that PHB sites offer more safety benefits, at the expense of increased vehicles' delay, compared to RRFB sites. The presence of the PHB, weekday, signal activation, lane count, pedestrian speed, vehicle speed, land use mix, traffic flow, time of day, and pedestrian starting position from the sidewalk have been found to be significant determinants of the SSMs and vehicles' delay. Another avenue of pedestrian safety explored in this dissertation is the lag time. The study investigates survival likelihood and the lag time of non-instant pedestrian fatalities using random parameter Binary Logit and Ordered Logit models. The models were run on a dataset obtained from the Fatality Accident Reporting System (FARS) for the period of 2015-2019. The analysis revealed that weather, driver age groups, drunk/ distracted/ drowsy drivers, hit and run, involvement of large truck, VRU age group, gender, presence of sidewalk, presence of intersection, light condition, and speeding were common significant factors for both models. The factor found to be significant exclusively for the Binary Logit model includes Area type. Factors found to be significant exclusively for the Ordered Logit model include Presence of Crosswalk and Fire station nearby. The results validate the use of lag time as an alternative to crash count and crash severity analysis. The findings of this study pave the way for practitioners and policymakers to evaluate the effectiveness of midblock pedestrian crossing facilities, as well as to use lag time to investigate crashes and corroborate results from traditional crash-based investigations.
7

Model za utvrđivanje uticaja izdvojenih nesignalisanih pešačkih prelaza na nivo usluge gradskih saobraćajnica / The influence of an unsignalized midblock crosswalk on the level of service of urban street segments estimating model

Garunović Nemanja 09 October 2020 (has links)
<p>Predmet ove doktorske disertacije su izdvojeni pešački prelazi odnosno njihov uticaj na uslove odvijanja motornog saobraćaja na gradskim saobraćajnicama. Ocenu uslova odvijanja motornog saobraćaja na gradskim saobraćajnicama između ostalog vrši se na osnovu brzine putovanja vozila prolaznog toka na odseku koja je u obrnuto proporcionalna sa vremenom putovanja vozila na odseku gradske saobraćajnice. Povećanje vremena putovanja zavisi od veličine ostvarenih vremenskih gubitaka koji nastaju na izdvojenom pešačkom prelazu. Ključna pretpostavka na kojoj je zasnovana ova doktorska disertacija je da vremenski gubici vozačkih tokova na izdvojenom pešačkom prelazu nastaju usled pojave pešaka (ili grupa pešaka) i kao takvi utiču na smanjenje prosečne brzine putovanja tj. povećanje vremena putovanja vozila na odseku. U skladu sa tim cilj rada je definisanje modela za utvrđivanje vremenskih gubitaka vozila na izdvojenim pešačkim prelazima uz mogućnost implementacije u postojećoj metodologiji za definisanje uslova odvijanja saobraćaja na odsecima gradskih saobraćajnica. U skladu sa definisanim ciljem izvršena je analiza prethodnih relevantnih istraživanja, a zatim i prikupljane podatka o uslovima odvijanja saobraćaja u realnom saobraćajnom toku. Sistematizacijom prikupljenih podataka i primenom odgovarajućih matematičkih i statističkih alata utvrđene su zakonitosti nastanaka vremenskih gubitaka vozačkih tokova koji nastaju na izdvojenom pešačkom prelazu i formiran model za njihov proračun.</p> / <p>The theme of this doctoral thesis is the analysis of the midblock pedestrian crossings influence on traffic conditions on urban street segments. The assessment of motor traffic conditions on urban street segments was carried out on the basis of travel speed of through vehicles. Travel speed of through vehicles for the segment represents the relation between the segment length and segment running time, which implies that running time increase directly affects travel speed decrease. Segment running time greatly depends on the value of the achieved delays which occur on a midblock pedestrian crossing. The key assumption, which this doctoral thesis is based on, is that delays of vehicular flows on midblock pedestrian crossings occur as a consequence of pedestrian (or a group of pedestrians) appearance and that they affect the travel speed of through vehicles decrease, that is, the increase of segment running time. Accordingly, the purpose of this paper is defining the model for determination of vehicular delays on midblock pedestrian crossings, with the possibility of its implementation into the existing methodology for defining traffic conditions on the urban street segments. In accordance with the defined aim within the doctoral thesis, the analysis of previous relevant research studies was carried out, and then the research in a real traffic flow. The systematization of the collected data and the application of the appropriate mathematical and statistical tools enabled how to establish the rules of vehicular flows delays occurrence on midblock pedestrian crossing. On the basis of the established rules and correlation of traffic and geometric characteristics of midblock pedestrian crossings, a model for calculating the value of delays occurring in traffic flows was defined.</p>

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