High Occupancy Toll (HOT) lanes were recently proposed for I-85 in Atlanta as a way to relieve congestion and provide a reliable commute time for single occupant drivers that are willing to pay a toll. It is important to evaluate the air quality impacts of such a proposal to meet environmental regulations, such as the National Environmental Policy Act (NEPA) and Transportation Conformity Regulations. The goal of this study is to understand how vehicle mass emissions change as a result of implementing HOT lanes on I-85 in Atlanta . This is done by considering a number of factors affect mass vehicle emissions, such as vehicle activity, vehicle speeds, vehicle age distributions, and vehicle class distributions. These factors are incorporated into a base scenario, which models the current condition on I-85 with HOV lanes, and a future scenario, which models the implementation of HOT lanes on this corridor. The base scenario mainly uses data from a data collection effort by Georgia Tech during the summer of 2007 on the I-85 corridor, while the future scenario makes alterations to these data using information from other cities that have already implemented HOT lanes. The MOBILE-Matrix modeling tool, which was recently developed by Georgia Tech [16], was used to run the emissions analysis using the input factors from these data sources. This tool calculated mass emissions for five pollutants: HC, NOx, CO, PM2.5, and PM10. The results show very small increases in mass emissions for NOx, CO, PM2.5, and PM10, and very small decreases in mass emissions for HC. Therefore, the implementation of HOT lanes on I-85 in Atlanta is unlikely to violate the Transportation Conformity Rule. For NEPA purposes, this analysis could be used to make the case that air quality impacts are not significant, and therefore further detailed analyses are not required.

Thesis (Ph.D.)--George Mason University, 2008. / Vita: p. 199. Thesis director: Roger Stough. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Public Policy. Title from PDF t.p. (viewed Mar. 16. 2009). Includes bibliographical references (p. 182-198). Also issued in print.

Long popular in northern Europe, protected bike lanes, also known as "cycle tracks" or "separated bike lanes," are seeing increased interest in the United States. One of the primary benefits of protected bike lanes is that they may provide a higher level of comfort than a standard bike lane that is only delineated by an inches-wide painted stripe. Several methods exist for quantifying the quality of service provided by a roadway for a bicyclist; however, many of these models do not consider protected bike lanes and of those that do, none are based on empirical data from the US. This is problematic as engineers, planners, and elected officials are increasingly looking to objective performance measures to help guide transportation project design and funding prioritization decisions. This thesis addresses this gap by presenting a cumulative logistic model to predict user comfort on protected bike lanes using surveys conducted in the United States. The model is for road segments only and not signalized intersections. It is developed from the results of in-person video surveys conducted in Portland, Oregon. The survey was completed by 221 individuals who viewed 20 video clips each. The model is validated using 3,230 responses to a survey of those who have ridden on protected bike lanes in multiple cities around the US. A cumulative logistic model is used because it predicts the distribution of ratings, providing a clearer picture of a facility's performance than a mean value produced by a simple linear model. The resulting model indicates that buffer type, one-way vs. two-way travel, motor vehicle speed, and motor vehicle average daily traffic volumes are all significant predictors of bicyclist comfort in protected bike lanes. Survey results also show that protected bike lanes are generally more comfortable than other types of on-street infrastructure, consistent with previous research findings.

Connected and automated vehicles (CAVs) will behave fundamentally differently than human drivers. In mixed traffic, this could lead to inefficiencies and safety-critical situations since neither human drivers nor CAVs will be able to fully anticipate or predict surrounding traffic dynamics. Thus, some researchers proposed to separate CAVs from conventional vehicles by dedicating exclusive lanes to them. However, the separation of road infrastructure can negatively impact the system’s capacity. While the effects of CAV lanes were addressed for freeways, their deployment in urban settings is not yet fully understood. This paper systematically analyzes the effects of CAV-lanes in an urban setting accounting for the corresponding complexities. We employ microscopic traffic simulation to model traffic flow dynamics in a detailed manner and to be able to consider a wide array of supply-related characteristics. These concern intersection geometry, public transport operation, traffic signal control, and traffic management. Our study contributes to the existing literature by revealing the potential of CAV lanes in an urban setting while accounting for the behavioral and topological complexities. The results of this study can support decision-makers in the design of future urban transportation systems and to prepare cities for the upcoming era of automation in traffic.

The High Occupancy Vehicle (HOV) lanes on Atlanta, Georgia’s radial I-85 had long been providing sub-optimal throughput in the peak traffic hours, as the two-person occupancy requirement allowed the lanes to become heavily congested. The Georgia Department of Transportation converted 15.5 miles of HOV 2+ lanes to High Occupancy Toll (HOT) lanes, one in each direction on I-85. The lanes use dynamic value pricing to set toll levels based on the volume and average speed of traffic in the lanes. The goal of this research was to investigate the responses to toll lane pricing and the factors that appear to inform lane choice decisions, as well as examining values of travel time savings and toll price elasticity for users of the Express Lanes. This study of the metropolitan Atlanta I-85 Express Lanes operates at the microscopic level to examine the impact of demographic characteristics, congestion levels, and pricing on users’ decisions to use or not use the I-85 Express Lanes. The dissertation examined the value of travel time savings distributions across income segments. The differences in these distributions among lower, medium, and higher income households were marginal at best. The results did not indicate that higher income households had the highest value of travel time savings results, as may have been expected. The modeling work performed here provided a number of insights into toll lane use. The determinants of lane choice decision-making in the morning peak had notable differences from the determinants of the afternoon peak. The initial analysis involved models which were estimated across three different income segments to examine differences in decision making between low, medium, and higher income households. The results indicated that the parameters were largely consistent across the three segments. Further segmenting the households showed that lane choice determinants varied more within the ‘Higher’ income segment than across the original three-segment structure. In particular, the five-segment models illustrated lower elasticities with regard to corridor segment counts and toll levels for the highest-income households in the sample, as well as higher household income level elasticities for afternoon trips by that same cohort. The research was among the first in the available literature to use revealed preference lane use data for both the toll lane users and the unpriced general purpose lane users. The use of household level marketing data, rather than census or survey data, was another unique characteristic of this research. The analysis of value of travel time savings with a demographic component that looks at household income has not yet been seen in the literature; similarly, the findings regarding differing behavior among very high income households appear to be unseen in the existing literature. The results from this analysis, such as willingness-to-pay values for different population segments, will be useful inputs to the decisions surrounding future HOT implementations in the Atlanta region. The use of new data sources, the evaluation of those types of data sources, and the application of methods that have previously been unused in this field make up the primary contributions of this dissertation.

published_or_final_version / Urban Studies / Master / Master of Social Sciences

Neste trabalho são investigadas as razões da maior utilização do sistema cicloviário na cidade de Rio Claro em relação à Araraquara e São Carlos, e descobrir os principais motivos da baixa demanda de usuários nas ciclovias e ciclofaixas das cidades de Araraquara e São Carlos. Esse objetivo visa compreender também o porquê da utilização ou não do espaço destinado ao tráfego de bicicletas. Tal objetivo auxilia na obtenção de informações que possam ajudar no planejamento e no projeto da implantação de ciclovias e ciclofaixas nas cidades brasileiras. Também é realizada uma avaliação individual dos segmentos cicloviários (ciclovias e ciclofaixas) existentes nas três cidades objeto do estudo e uma avaliação geral do sistema cicloviário das mesmas, mediante, sobretudo, a comparação de dados quantitativos. O uso muito maior do modal bicicleta em Rio Claro deve-se aos seguintes principais fatores: preponderância de vias com baixa declividade na maior parte da área urbana, qualidade insatisfatória do transporte coletivo nas últimas décadas, renda média inferior da população e maior influência da cultura europeia (alemã e italiana) na colonização da cidade- países que têm grande tradição no uso da bicicleta. Os principais fatores inibidores do uso do modal bicicleta em São Carlos são: topografia acidentada (em grande parte da área urbana as vias tem rampas acentuadas), maior nível de desenvolvimento socioeconômico e falta de tradição/cultura do uso da bicicleta. Em Araraquara, são: boa qualidade do transporte coletivo nas últimas décadas, maior nível de desenvolvimento socioeconômico e falta de tradição/cultura do uso da bicicleta. São ainda discutidos os seguintes pontos relevantes: tipos de segmentos cicloviários x visão da população, impacto da bicicleta na fluidez do trânsito e segurança no uso da bicicleta. / This research investigates the reasons for the increased use of cycling system in the city of Rio Claro in relation to Araraquara and São Carlos, and discover the main reasons for the low demand of users in bicycle tracks and lanes of the cities of Araraquara and São Carlos. This goal also aims to understand why the use or not of the installation to bicycle traffic. This goal is important to obtain information that may help in the planning and implementation of bicycle paths and lanes project in Brazilian cities. An individual evaluation of existing cycling segments (bike paths and lanes) in the three cities subject of the study and an overall assessment of cycling system of them, highlighting the comparison of quantitative data performed. The far greater use of the bicycle modal in Rio Claro is due to the following main factors: preponderance of routes with low slope in most of the urban area, poor quality of public transport in recent decades, lower average incomes and greater influence of culture European (German and Italian) in the colonization of the city- countries that have great tradition in bicycle use. The main factors inhibiting the use of bicycle modal in São Carlos are: topography (largely urban area routes have steep ramps), higher level of socioeconomic development and lack of tradition/culture of cycling. In Araraquara, are: better quality of public transport in recent decades, higher socioeconomic level of development and lack of tradition/culture of cycling. Are still discussed the following relevant points: types of cycling segments x populations point of view, impact of bicycles in traffic flow and safety on bicycle use.

Neste trabalho são investigadas as razões da maior utilização do sistema cicloviário na cidade de Rio Claro em relação à Araraquara e São Carlos, e descobrir os principais motivos da baixa demanda de usuários nas ciclovias e ciclofaixas das cidades de Araraquara e São Carlos. Esse objetivo visa compreender também o porquê da utilização ou não do espaço destinado ao tráfego de bicicletas. Tal objetivo auxilia na obtenção de informações que possam ajudar no planejamento e no projeto da implantação de ciclovias e ciclofaixas nas cidades brasileiras. Também é realizada uma avaliação individual dos segmentos cicloviários (ciclovias e ciclofaixas) existentes nas três cidades objeto do estudo e uma avaliação geral do sistema cicloviário das mesmas, mediante, sobretudo, a comparação de dados quantitativos. O uso muito maior do modal bicicleta em Rio Claro deve-se aos seguintes principais fatores: preponderância de vias com baixa declividade na maior parte da área urbana, qualidade insatisfatória do transporte coletivo nas últimas décadas, renda média inferior da população e maior influência da cultura europeia (alemã e italiana) na colonização da cidade- países que têm grande tradição no uso da bicicleta. Os principais fatores inibidores do uso do modal bicicleta em São Carlos são: topografia acidentada (em grande parte da área urbana as vias tem rampas acentuadas), maior nível de desenvolvimento socioeconômico e falta de tradição/cultura do uso da bicicleta. Em Araraquara, são: boa qualidade do transporte coletivo nas últimas décadas, maior nível de desenvolvimento socioeconômico e falta de tradição/cultura do uso da bicicleta. São ainda discutidos os seguintes pontos relevantes: tipos de segmentos cicloviários x visão da população, impacto da bicicleta na fluidez do trânsito e segurança no uso da bicicleta. / This research investigates the reasons for the increased use of cycling system in the city of Rio Claro in relation to Araraquara and São Carlos, and discover the main reasons for the low demand of users in bicycle tracks and lanes of the cities of Araraquara and São Carlos. This goal also aims to understand why the use or not of the installation to bicycle traffic. This goal is important to obtain information that may help in the planning and implementation of bicycle paths and lanes project in Brazilian cities. An individual evaluation of existing cycling segments (bike paths and lanes) in the three cities subject of the study and an overall assessment of cycling system of them, highlighting the comparison of quantitative data performed. The far greater use of the bicycle modal in Rio Claro is due to the following main factors: preponderance of routes with low slope in most of the urban area, poor quality of public transport in recent decades, lower average incomes and greater influence of culture European (German and Italian) in the colonization of the city- countries that have great tradition in bicycle use. The main factors inhibiting the use of bicycle modal in São Carlos are: topography (largely urban area routes have steep ramps), higher level of socioeconomic development and lack of tradition/culture of cycling. In Araraquara, are: better quality of public transport in recent decades, higher socioeconomic level of development and lack of tradition/culture of cycling. Are still discussed the following relevant points: types of cycling segments x populations point of view, impact of bicycles in traffic flow and safety on bicycle use.

Emergency response times have been shown to be directly correlated with mortality rates of out-of-hospital patients. Studies have been conducted to show the relationship between time and mortality rates until patients receive the proper treatment. With more cardiac arrests and other life threatening illnesses occurring in the United States, more emergency calls will be required as well. As of today, technological advancements have been made to reduce response times, but human factors still require certain procedures, causing delays in the run time and increasing the rate of mortality. Here we show the results of emergency response times with the market penetration of connected and autonomous vehicles. With connected and autonomous vehicles, the average time emergency vehicles spend on the roadways can be significantly decreased. Safety procedures with human drivers can be eliminated, giving the emergency vehicle a proper right-of-way through virtual emergency lanes and removing the need to slow down and avoid vehicles at intersections or during periods of heavy congestion. Our results show a three minute decrease in response time under full market penetration of the technology, reducing the mortality rate and increasing the potential to save lives.

Most safety analysis is conducted using crash data. Surrogate safety measures, such as various time-based measures of time-to-collision can be related to crash potential and used to gain insight into the frequency and severity of crashes at a specific location. One of the most common and acknowledged measures is post-encroachment time (PET) which defines the time between vehicles occupying a conflicting space. While commonly used in studies of motor vehicle interactions, studies of PET for bicycle-vehicle interactions are few. In this research, the PET of bicycle-vehicle interactions measured in the field, a driving simulator, and in a micro-simulation are compared. A total of 52 right-hook conflicts were identified in 135 hours of video footage over 14 days at a signalized intersection in Portland, OR (SW Taylor and SW Naito Pkwy). The results showed that 4 of 17 high-risk conflicts could not be identified by the conventional definition of PET and PET values of some conflicts did not reflect true risk of collision. Therefore, right-hook conflicts were categorized into two types and a modified measure of PET was proposed so that their frequency and severity were properly measured. PETs from the field were then compared to those measures in the Oregon State University driving simulator during research conducted by Dr. Hurwitz et al. (2015) studying the right-hook conflicts. Statistical and graphical methods were used to compare field PETs to those in the simulator. The results suggest that the relative validity of the OSU driving simulator was good but not conclusive due to differences in traffic conditions and intersections. To further explore the field-observed PET values, traffic simulation models of the field intersection were developed and calibrated. Right-hook conflicts were extracted from the simulation files and conflicts observed in PM-peak hours over 6 days in the field were compared to those obtained from 24 traffic simulation runs. The field-observed PET values did not match the values from the simulation values very well. However, the approach does show promise. Further calibration of driving and bicycling behaviors would likely improve the result.