There is increased interest in building modern roundabouts in Georgia and in the United States because of the safety and operational benefits that can be realized from this type of intersection. With this interest comes the increasing need to be able to estimate the capacity that a roundabout can provide after it is built. In the early 2000s, a National Cooperative Highway Research Program (NCHRP) study was conducted that, among other tasks, developed single-lane and multi-lane roundabout capacity estimation equations. These equations, presented in the Highway Capacity Manual 2010 (HCM 2010), can be calibrated using locally determined values of follow-up headway and critical headway. This study was designed to calibrate the HCM 2010 roundabout capacity equation for single-lane roundabouts to driving conditions in Georgia. In order to develop estimates of the calibration parameters, video imagery was recorded for 13 approaches at six roundabouts in Georgia for approximately two hours during the peak period. A total of 29.5 hours of video was recorded. Data from three of these roundabouts forms the basis of this thesis. The videos were processed by a Java program to collect time stamps that were subsequently used in Microsoft Excel to calculate the follow-up and critical headway values required for calibration. The values of critical headway and follow-up headway that were found from the video data are presented in the results as well as the single-lane capacity equations calibrated from the data. Two types of analysis were done, one that includes exiting vehicles and one that does not include exiting vehicles. When exiting vehicles were excluded, the weighted average of follow-up and critical headway were found to be 3.46 and 4.17 seconds respectively and when exiting vehicles were included in the analysis the weighted averages of the follow-up and critical headway were found to be 2.80 seconds and 3.34 seconds respectively. It was found that exiting vehicles do have an impact on the operations at the roundabout in most cases, and including exiting vehicles in the analysis tends to increase the capacity predicted by the calibrated equations.

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The operational performance of an existing or proposed roundabout can be assessed through capacity models. In order to provide improved capacity predictions for existing and proposed Georgia roundabouts, the 2010 HCM roundabout capacity equations need to be locally calibrated based on Georgia drivers. The purpose of this study is to collect field data necessary to calculate follow-up and critical headways at Georgia roundabouts in order to calibrate the 2010 HCM capacity equations to yield improved capacity predictions. The research team filmed 28 approaches at thirteen Georgia roundabouts for a total of 56.5 hours. The video was processed manually using an in-house computer program. Based on analyst keystrokes during the video review the program would extract timestamps of events that are necessary for calculating follow-up and critical headway. The follow-up and critical headway values were calculated for two different data sets: 1) including exiting vehicles and 2) excluding exiting vehicles. The critical and follow-up headway for an analysis including exiting vehicles is 4.192 seconds and 2.788 seconds respectively. The critical and follow-up headway for an analysis excluding exiting vehicles is 4.747 seconds and 3.265 seconds respectively. This study found that including the exiting vehicles impacts the capacity. The capacity increases or decreases based on the percentage of conflicting vehicles that are exiting vehicles. In addition, this study’s calibrated model excluding exiting vehicles predicts higher capacity than the 2010 HCM model that GDOT recommends which also excludes exiting vehicles.

The aim of this Master's thesis is design of possible modifications of crossroad I/55 and II/432, primarily with focus on capacity and safety. The first part of this thesis is dealing with measurement and evaluation of current traffic intensities, and capacity calculations of suggested design modifications. The second part of the thesis consists of detailed project of one design modification (diamond interchange) for documentation for construction permit.

Subject of this thesis is a modification of an existing arrangement junction which does not meet current traffic demands. The adjustment includes two lane roundabout road I/11,1/33 and I/35 near ČKD in Hradec Králové. The proposed solution is based on requirements of the regional office of Hradec Králové region. One part of the thesis includes the capacity assessment of the proposed amendments.

The subject of my Master’s thesis is the variant redevelopment of level crossings I/45 and I/11 nearby bus terminal in Bruntál in Moravian-Silesian region. The current design isn’t well arranged and the crossroad is place of frequent traffic accidents. There are four solutions of existing crossroad. In the frame of variants, there is a different manner of solution of structural layout of crossroad, possibility of connection of shopping center and solution of pedestrian traffic. The thesis includes traffic survey, evaluation of accidents, capacity analysis of existing crossroad and four new solutions and estimate of building costs.