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<p> Traffic operations can be described by the relationship that occurs between flow and occupancy. This paper investigates the flow-occupancy relationship of an Ontario system and a Minnesota system to see if the same general relationship occurs in different locations. It is hoped that this investigation will help to further the work being done at McMaster in developing a new incident detection algorithm.</p> <p> In comparing the two data sets, simple analytical procedures were employed to compare the full data set, the uncongested regime, and the calculated fitted lines for the uncongested data. Visual comparison was the basis for much of the analysis.</p> <p> When the comparisons were conducted the relationships were indeed very similar, signifying that the flow-occupancy relationship is the same for different locations.</p> / Thesis / Candidate in Philosophy

The dissertation examines the relationship between the number of lane changes, the speed of the ramp lane, and the location upstream of the ramp split. Analyses indicate the number of lane changes exhibits a parabolic relationship with respect to the ramp lane speed, and the number of lane changes exhibits gamma-distributed relationship with respect to the distance upstream of the ramp. The macroscopic lane changing model presented is best characterized as the development of generalized lane-changing relationships, and provides a starting point from which more complex corridor-level models can be developed. This study also identifies an unusual car-following behavior exhibited by certain lane-changing drivers. When the target lane is moving slowly, some lane-changing drivers will slow down, causing a disruption in their initial lane. Regression analysis is used to estimate the speed upstream of the initial lane to indicate the disruption is responsible for the lateral propagation of congestion. The lane choice of exiting vehicles is also studied. Lane choice appears to be a function of origin/destination, and freeway speed. As speeds in the general purpose lanes decrease, exiting vehicles are more likely to wait longer to move into the exit ramp lanes, resulting in an increased lane changing density. Results from this study are expected to have the greatest impact on microscopic lane-change model validation. Additionally, results have implications for design and safety issues associated with freeway ramps. As data collection technologies improve and data becomes increasingly available, this research provides the basis for the further development of more elaborate lane-changing models.

Driving the wrong way on freeways has been a nagging traffic safety problem since the interstate highway system was founded in the 1950s. Despite four decades of highway striping and sign improvements at freeway interchanges, the problem persists. This paper is to determine the contributing factors to wrong-way driving on freeways and to develop promising, cost-conscious countermeasures to reduce this driving errors and related crashes. Wrong-way crash data from Illinois Department of Transportation (IDOT) crash database were collected with 632 possible wrong-way crashes. The real wrong-way crashes were further identified by reviewing the wrong-way crash reports hardcopies and information from other resources. Characteristics of wrong-way driving behaviors were analyzed and statistical analyses were conducted to identify the contributing factors of wrong-way crashes on freeway. The state-of-the-art roadway safety management process recommended by the Highway Safety Manual (HSM) was adopted to diagnose the wrong-way driving behavior on Illinois freeway and develop the specific wrong-way crashes management procedures. The first three steps, network screening, diagnosis and countermeasure selection was developed in details. The whole procedure developed could be used to guide the management of freeway wrong-way crashes in the future. The specific procedure of transportation network review, candidate location identification and site ranking for freeway wrong-way crashes was established firstly. Based on the collected wrong-way crash data, the safety performance function (SPF) for wrong-way crashes on freeway was developed with the annual average daily traffic (AADT) and segment length being the independent variables. The procedures for candidate wrong-way crash sites diagnoses with crash data, historic site data, field condition and other information were described step by step. The methods for contributing factors identification were proposed and the Haddon matrix for wrong-way crashes on freeway was constructed finally. Methods for selecting wrong-way crash countermeasures from the perspective of "four E's" based on crash analysis finding, site-specific contributing factors and geographical characteristics were discussed, and research needs on wrong-way crash management in the future were recommended finally.

This study provides an insight into the impact of construction activities on traffic operations. Specifically, the topic of interest for this thesis is to study the impact of construction on traffic operations for construction projects on Interstate 4 from SR 434 to John Young Parkway, from SR 528 to SR 535, and from SR 482 to SR 528. These three projects were chosen because they were the only projects on Interstate 4 where both construction data and loop detector data were available for analysis. The data was collected by examining the Florida Department of Transportation daily inspection reports which had detailed documentation of construction operations that took place. The following information was collected: date, type of construction work being performed, time, location, and direction of impact to the traveling public. These data points were cross-referenced to the loop detector stations and mile posts to collect the loop detector data and roadway geometric characteristics such as location of ramps, type of median, etc. The loop detector data (speed, volume, and occupancy) were collected and aggregated for the data analysis. The loop detector data were collected during construction, one year prior to construction, and one year after construction for comparison purposes. Logistic regression analysis under the within-stratum matched sampling framework was conducted as an exploratory analysis to see if there was a difference on the traffic impacts with and without construction. This was done by matching the variables to ensure that there were no other differences impacting the traffic operations. Logistic regression proved there was a difference in the traffic operations with and without the presence of construction. The simple model results demonstrated that speed was reduced, occupancy was increased, and volume decreased during construction. After construction, the speed and volume increased and the occupancy decreased. Linear regression and analysis of covariance were used to quantify the impact of the various construction activities on the speed, occupancy and volume. Linear regression and analysis of covariance were used to understand the impacts from the presence of roadway geometrics on freeway traffic operations during construction. Logistic regression controls the geometrics, linear regression and analysis of covariance demonstrated how the geometrics impacted the construction effects. The geometric characteristics of each area were included in this analysis. This thesis investigates construction activities and roadway geometric parameters that impact traffic freeway operations (speed, volume, and occupancy) before, during, and after construction. This research showed the impact of different types of construction operations in a highway construction widening project. This research demonstrated that construction activities have a significant impact on speed, volume, and occupancy. Different types of construction activities have more of an impact than other activities. Paving had the highest adverse impact. Agencies writing construction contracts should prohibit paving during the most highly congested times. For example, in Orlando, Florida on Interstate 4, agencies should prohibit night paving during the peak holiday seasons (such as Thanksgiving, spring breaks, Christmas, etc.) around the tourist attractions during closing times, during the peak morning hours, and during the closing times of high attendance activities, such as Halloween Horror Nights at Universal Studios when high attendance is anticipated at the theme parks. Roadway geometrics also impact the traffic operations differently, before, during, and after construction and differently during various times of the day. The information of improved roadway geometrics and faster traffic flow can be used at open houses for upcoming projects where there are many people opposed to construction projects to show how the roadway construction projects actually increase traffic flow, helping everyone to get to their destinations much faster. The impact of the traffic delays in the congested areas, such as the tourist areas on Interstate 4 during the peak traffic times could be quantified to calculate delay costs to the roadway users.

The highway, its promise of freedom and mobility, stands as a source of intrigue in American culture. Yet, the asphalt and dashed lines that cut across the country conceal the contentious history that accompanied interstate highway construction. This dissertation examines the social and spatial meanings of interstate highway plans in the United States at different historical and geographic scales. This account begins in the late 1930's and travels through the mid 1940's where I discuss Norman Bel Geddes's 1939 Worlds Fair Exhibit, "Futurama" and Robert Moses's 1944 Baltimore Arterial Report. This analysis demonstrates how each man inscribed social values into proposed developments within geographic space. From here I move to Baltimore where from 1944 until about 1979, countless proposals called for the construction of an arterial highway that would cut into the heart of the city. By drawing from the archival records left by Movement Against Destruction (MAD), Relocation Action Movement (RAM), and other groups in that fought against roadway plans in Baltimore, I explore how activists lived, understood, and challenged the new social arrangements embedded in the proposed highway system. I introduce the term infrastructural imaginaries to account for how the proposal or construction of spatially embedded systems seeks to transform lived material and geographic arrangements. The concept of infrastructural imaginaries expands upon Sheila Jasanoff and San-Hyun Kim's "sociotechnical imaginaries" to address how proposed futures appropriate spatial environments and how people lived, understood, and conceptualize themselves within these emergent spaces. The framework of infrastructural imaginaries utilizes Henri Lefebvre's conceptual triad of spatial practice, representations of space, and representational space to analyze the dynamic interactions between infrastructure planning, lived experience, and articulations of possible futures. To study the infrastructural imaginary, the immaterial form, provides a fertile space from which to isolate places where systems fail to take hold, where alternative understanding emerge, and where new forms social interaction takes place. / Ph. D. / The interstate highway, its promise of freedom and mobility, stands as a source of intrigue in American culture. Yet, the asphalt and dashed lines that cut across the country conceal the contentious history that accompanied interstate highway construction. Following the passage of the 1956 Federal Aid Interstate Highway Act movements called ‘freeway revolts’ began in cities across the United States. These protests resisted the construction of highways in urban areas. Additionally, these social movements called attention to the planning practices that condemned the houses of low income and minority populations, clear-cut park land, and disrupted the urban fabric. This dissertation examines Baltimore’s ‘freeway revolt’ using archival documents left by the many activist groups who participated in attempting to stop the highway. Rather than presenting a comprehensive history of these events, this dissertation pays attention to how social understandings of geographic space contributed to highway plans, organized activism, and the practices of those who lived under the threat of impending infrastructure.

With the passage of the Federal Aid Highway Act of 1956, the interstate system included an elevated segment of Interstate 10 constructed over Claiborne Avenue in New Orleans, Louisiana. The I-10 Claiborne Expressway provided access to downtown by destroying a tree-lined boulevard and contributing to the decline of an African American neighborhood. In 2005, after hurricane Katrina, several community-based plans proposed that the elevated I-10 Claiborne Expressway be removed. This thesis compares the removal proposals to the decision making processes of five case cities that have removed expressways. Necessary conditions were applied to all expressway removal cases. Currently, the I-10 Claiborne Expressway decision making process lacks defined structural integrity and safety concerns, a reduction in the value of freeways by power brokers, documented support of the business community and “selling” of idea by a public agency. These conditions were necessary to the decision to remove expressways in all case cities.

This dissertation evaluates contraflow during a hurricane evacuation for grade separated highways. Contraflow is the concept of reversing the typical direction of highway travel to provide more outbound roadway capacity. The State of Florida has spent more time and resources towards the planning and the designing of potential contraflow facilities than any other state in the country; however, contraflow has yet to be implemented (as of Summer 2008). This study determines if the additional capacity benefits of contraflow outweigh the logistical requirements of implementing contraflow. Five different alternatives of contraflow lane configurations were comparatively evaluated. The format of this study is unique due to the evaluation of both capacity and logistical measurements. Each alternative was subject to evaluation of six different performance measures. The six different performance measures consisted of improved capacity, speed variation, logistics, required personnel, required infrastructure, and delay/congestion. Each performance measure was evaluated using a scaled scoring system. The alternative with the lowest average scoring among the different performance measures was considered the best alternative. Contraflow should only be considered as a last resort. The loss of inbound access, safety concerns,logistical requirements, and the additional strain of public resources during an evacuation are negative aspects that should be considered when determining the capacity benefit. If extenuating circumstances justify contraflow, then a full conversion of all inbound lanes to outbound lanes, known as Alternative D, should be considered. This alternative demonstrated the greatest capacity benefit while requiring the least amount of public resources. However, instead of contraflow, it is suggested to divert public resources towards other, more practical alternatives. Real time traffic monitoring has been demonstrated to be quite useful. Publicly accessed web-pages on the internet and the recent installation of variable message signs all provide improved notification of traffic conditions and of the capability to use alternative "atgrade" evacuation routes in addition to using the grade separated highways. This driver notification and the ability to ensure the safe and efficient travel on these alternative routes may be worth further investment, as well as being a potential topic of future research.

Variable Speed Limit Sign (VSLS) systems enable transportation managers to dynamically change the posted speed limit in response to prevailing traffic and/or weather conditions. VSLS are thought to improve safety and reduce driver stress while improving traffic flow and travel times. Although VSLS have been implemented in a limited number of jurisdictions throughout the world, there is currently very limited documentation describing the quantitative safety and operational impacts. The impacts that have been reported are primarily from systems in Europe, and may not be directly transferable to other jurisdictions, such as North America. Furthermore, although a number of modelling studies have been performed to date that quantify the impacts of VSLS, the VSLS control strategies are often too complex or based on unrealistic assumptions and therefore cannot be directly applied for practical applications. Consequently, a need exists for an evaluation framework that quantifies the safety and traffic performance impacts of comprehensive VSLS control strategies suitable for practical applications in North America. This paper presents the results of an evaluation of a candidate VSLS system for an urban freeway in Toronto, Canada. The evaluation was conducted using a microscopic simulation model (i. e. a model that predicts individual vehicle movements) combined with a categorical crash potential model for estimating safety impacts. <br /><br /> The objectives of this thesis are: 1) to validate a real-time crash prediction model for a candidate section of freeway; 2) to develop a candidate VSLS control algorithm with potential for practical applications; 3) to evaluate the performance of the VSLS control strategy for a range of traffic conditions in terms of safety and travel time; and 4) to test the sensitivity of the VSLS impact results to modifications of the control algorithm. <br /><br /> The analysis of the VSLS impacts under varying levels of traffic congestion indicated that the candidate control strategy was able to provide large safety benefits without a significant travel time penalty, but only for a limited range of traffic conditions. The tested algorithm was found to be insufficiently robust to operate effectively over a wide range of traffic conditions. However, by modifying parameters of the control algorithm, preliminary analysis identified potential improvements in the performance of the VSLS. The modified control strategy resulted in less overall travel time penalty without an adverse impact on the safety benefits. It is anticipated that further modifications to the VSLS control strategy could result in a VSLS that is able to operate over a wide range of traffic conditions and provide more consistent safety and travel time benefits, and it is recommended that the framework used in this study is an effective tool for optimizing the algorithm structure and parameter values.

Variable Speed Limit Sign (VSLS) systems enable transportation managers to dynamically change the posted speed limit in response to prevailing traffic and/or weather conditions. VSLS are thought to improve safety and reduce driver stress while improving traffic flow and travel times. Although VSLS have been implemented in a limited number of jurisdictions throughout the world, there is currently very limited documentation describing the quantitative safety and operational impacts. The impacts that have been reported are primarily from systems in Europe, and may not be directly transferable to other jurisdictions, such as North America. Furthermore, although a number of modelling studies have been performed to date that quantify the impacts of VSLS, the VSLS control strategies are often too complex or based on unrealistic assumptions and therefore cannot be directly applied for practical applications. Consequently, a need exists for an evaluation framework that quantifies the safety and traffic performance impacts of comprehensive VSLS control strategies suitable for practical applications in North America. This paper presents the results of an evaluation of a candidate VSLS system for an urban freeway in Toronto, Canada. The evaluation was conducted using a microscopic simulation model (i. e. a model that predicts individual vehicle movements) combined with a categorical crash potential model for estimating safety impacts. <br /><br /> The objectives of this thesis are: 1) to validate a real-time crash prediction model for a candidate section of freeway; 2) to develop a candidate VSLS control algorithm with potential for practical applications; 3) to evaluate the performance of the VSLS control strategy for a range of traffic conditions in terms of safety and travel time; and 4) to test the sensitivity of the VSLS impact results to modifications of the control algorithm. <br /><br /> The analysis of the VSLS impacts under varying levels of traffic congestion indicated that the candidate control strategy was able to provide large safety benefits without a significant travel time penalty, but only for a limited range of traffic conditions. The tested algorithm was found to be insufficiently robust to operate effectively over a wide range of traffic conditions. However, by modifying parameters of the control algorithm, preliminary analysis identified potential improvements in the performance of the VSLS. The modified control strategy resulted in less overall travel time penalty without an adverse impact on the safety benefits. It is anticipated that further modifications to the VSLS control strategy could result in a VSLS that is able to operate over a wide range of traffic conditions and provide more consistent safety and travel time benefits, and it is recommended that the framework used in this study is an effective tool for optimizing the algorithm structure and parameter values.