Alternative intersections and interchanges, such as the diverging diamond interchange (DDI), the restricted crossing u-turn (RCUT), and the displaced left-turn intersection (DLT), have the potential to both improve safety and reduce delay. However, partially due to lingering questions about analysis methods and service measures for these designs, their rate of implementation remains low. This research attempts to answer three key questions. Can alternative intersections and interchanges be incorporated into the existing level of service and service measure schema, or is a new service measure with an updated level of service model required? Is the behavior of drivers at alternative intersections fundamentally similar to those at conventional intersections, such that traffic microsimulation applications can accurately model the behaviors observed in the field? Finally, is the planning level tool made available through FHWA an accurate predictor of the relative performance of various alternatives, or is an updated tool necessary? Discussion and case study analysis are used to explore the existing level of service and service measure schema. The existing control delay measure is recommended to be replaced with a proposed junction delay measure that incorporates geometric delay, with the existing level of service schema based on control type recommended to be replaced by a proposed schema using demand volume. A case study validation of micro- and macroscopic analysis methods is conducted, finding the two microscopic methods investigated to match field observed vehicle delays within 3 to 7 seconds for all designs tested, and macroscopic HCM method matching within 3 seconds for the DDI, 35 seconds for the RCUT, and 130 seconds for the DLT design. Taking the critical lane analysis method to be a valid measure of operations, the demand-volume limitations of each alternative design is explored using eighteen geometric configurations and approximately three thousand volume scenarios, with the DLT design predicted to accommodate the highest demand volumes before failure is reached. Finally, six geometries are examined using both the planning-level tool and the validated microsimulation tool, finding that the curve of the capacity-to-delay relationship varies for each alternative design, invalidating the use of critical lane analysis as a comparative tool. / Ph. D.

Improving intersection safety and efficiency are the primary goals of alternative intersection designs. These designs seek to improve on traditional traffic control methods, often by reducing intersection conflict points, reducing or eliminating time-wasting signal phases, or both. However, public opposition to these new designs can be a large barrier to implementation of alternative intersections despite their known safety and efficiency benefits.<br><br>This study evaluated current public perception and factors influencing that perception for four alternative intersection designs - the roundabout, the restricted crossing U-turn (also known as J-turn and reduced conflict intersection), the displaced left turn (also known as the continuous flow intersection), and the diverging diamond interchange (also known as the double crossover diamond interchange). <br><br>To achieve this objective, a survey instrument was designed and distributed to a target sample of 1,000 adults residing in the State of Indiana. The survey solicited participant awareness of these designs, acceptance of a potential implementation of the design in their community, and driver confidence using the design along with participant socio-demographic data. Descriptive and inferential statistical analysis was then conducted. <br><br>The survey results indicate that residents of Indiana are not aware of designs not currently widely implemented in the state, that opposition to these rarer designs is prominent, and that drivers were generally less confident in their ability to safely navigate these unfamiliar designs. Younger respondents, male respondents, more highly educated respondents, respondents who travel more often or for farther distances, and respondents who rate their own driving ability highly are more likely to be aware, accepting, and confident using alternative designs. <br><br>The results of this study will inform future outreach efforts pertaining to alternative intersections by improving transportation agency understanding of public opinions and primary concerns regarding these designs and provide potential paths for improving public perception. <br>