Document Type


Date of Award


Degree Name

Doctor of Philosophy in Transportation - (Ph.D.)


Civil and Environmental Engineering

First Advisor

Janice Rhoda Daniel

Second Advisor

I-Jy Steven Chien

Third Advisor

Lazar Spasovic

Fourth Advisor

Branislav Dimitrijevic

Fifth Advisor

Athanassios K. Bladikas


The recent publication of the 6th Edition of the Highway Capacity Manual included a chapter on Ramp Terminals and Alternative Intersections that introduces various alternative intersection designs and assesses the performance of Median U-turn, Restricted crossing U-turn and Displaced left-turn intersections. Missing from the literature is an alternative intersection selection tool for identifying whether an alternative intersection would be successful under local conditions. With limited information of organized alternative intersection research, most planners must rely heavily on their personal judgement while selecting the most suitable intersection designs. As appealing as alternative intersections are, there is no comprehensive methodology for planners to evaluate all possible designs and locate the best option.

Several studies have been performed on identifying the selection of the most appropriate alternative intersection. As straightforward as they are, they failed to accommodate the Highway Capacity Manual (HCM) and are highly dependent on the professional judgment of the planners. This dissertation aims to design a selection methodology that is easy to use and HCM compatible and independent of personal judgments.

The selection procedure is composed of three stages. The goal of the first stage is to clarify the objectives and concerns of planners in the selection of candidate intersections. This stage should identify the treatment objectives (for existing intersections) and stakeholders’ concerns (for new intersections). If more than one objective were identified, the planners should assign a weight for each objective. A questionnaire should be used in collecting this information. The second stage is to filter out some candidate designs before the detailed analysis. This stage tries to generalize the range of application for each Unconventional Alternative Intersection Design (UAID). Any design that cannot satisfy the capacity and Right-of-Way (ROW) requirement is deleted from future analysis. In stage three of the selection process, the alternative intersection designs selected for consideration are ranked and assessed based on the treatment purposes/stakeholders’ interests, which may likely include increasing mobility or safety.

By identifying a primary parameter used to score or rank all the considered intersections, the alternative intersection selection tool would assist planners to compare different intersection designs and to describe the intersection performance comprehensively. The primary parameter should account for both mobility and safety at each of the intersections evaluated. For intersection mobility, the evaluation process relies on methodologies provided in the Highway Capacity Manual 2016. For the safety assessment, a safety evaluation procedure is also developed to provide an overall assessment of the safety performance at the evaluated intersection. A selection algorithm is then designed to rank all intersections based the intersection performance.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.