Civil Engineering

 

First Advisor

Aemal Khattak

Date of this Version

5-2019

Comments

A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of the Requirements For the Degree of Master of Science, Major: Civil Engineering, Under the Supervision of Professor Aemal Khattak. Lincoln, Nebraska: May, 2019

Copyright 2019 Timothy Adams

Abstract

This study examines the potential for replacing the standard intersection design at two-way stop control (TWSC) and all-way stop control (AWSC) intersections along rural highways with a roundabout or a restricted crossing u-turn (RCUT) facility. The geometry of the RCUT design prohibits left and through movements from the side road, and provides a u-turn location downstream from the main crossing. This type of facility has been implemented for rural highways extensively in other states and has the potential to serve as a cost-effective solution to improve roadway safety within Nebraska.

Comparative analysis is conducted for three site locations (Humphrey, Madison, and Dakota City, Nebraska) with either TWSC or AWSC existing geometry, analyzing the anticipated impacts of mitigation with a roundabout or an RCUT design. The costs and benefit analysis from implementing the various intersection geometries includes monetized delay costs, monetized crash costs, and anticipated construction costs.

Alongside the cost benefit analysis, a decision matrix seeks to assess specifically whether an RCUT intersection would be appropriate, and the five factors for consideration identified include (1) the safety concerns at the location, (2) the overall levels of traffic demand, (3) the balance between major and minor movement traffic demand, (4) the presence of obstructions along the main roadway that would impact u-turn bay placement, and (5) the available space in the median for the u-turn bay.

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