Engineering Commons^™

Pavement Condition Index And Cost Of Ownership Analysis On Preventative Maintenance Projects In Kentucky, Dominic J. Michels

Theses and Dissertations--Civil Engineering

The Commonwealth of Kentucky has seen increasing use over time of preventative maintenance treatments on its asphalt pavements. Performance of two of the most prevalent treatments employed by the Kentucky Transportation Cabinet (KYTC) – Thin Asphalt Overlay (Thinlay) and Microsurfacing – had yet to be examined in-depth through condition surveys. This thesis describes the data collection process to find the Pavement Condition Index (PCI) of each preventative maintenance site in Kentucky from the last 10 years. With PCI from each site, deterioration curves were generated for each treatment – providing the estimated life extension benefit of each. The analysis then …

Incorporating Travel Time Reliability Into Transportation Network Modeling, Xu Zhang

Theses and Dissertations--Civil Engineering

Travel time reliability is deemed as one of the most important factors affecting travelers’ route choice decisions. However, existing practices mostly consider average travel time only. This dissertation establishes a methodology framework to overcome such limitation.

Semi-standard deviation is first proposed as the measure of reliability to quantify the risk under uncertain conditions on the network. This measure only accounts for travel times that exceed certain pre-specified benchmark, which offers a better behavioral interpretation and theoretical foundation than some currently used measures such as standard deviation and the probability of on-time arrival.

Two path finding models are then developed by …

Prediction Of Protected-Permissive Left-Turn Phasing Crashes Based On Conflict Analysis, Shraddha Sagar

Theses and Dissertations--Civil Engineering

Left-turning maneuvers are considered to be the highest risk movements at intersections and two-thirds of the crashes associated with left-turns are reported at signalized intersections. Left-turning vehicles typically encounter conflicts from opposing through traffic. To separate conflicting movements, transportation agencies use a protected-only phase at signalized intersections where each movement is allowed to move alone. However, this could create delays and thus the concept of a protected-permissive phase has been introduced to balance safety and delays. However, the permissive part of this phasing scheme retains the safety concerns and could increase the possibility of conflicts resulting in crashes. This research …

Safety-Based Guidelines For Left-Turn Phasing Decisions With Negative Binomial Regression, Kiriakos Amiridis

Theses and Dissertations--Civil Engineering

The efficient and safe movement of traffic at signalized intersections is the primary objective of any signal phasing and timing plan. Accommodation of left turns is more critical due to the higher need for balancing operations and safety. The objective of this study is to develop models to estimate the safety impacts of the use of left-turn phasing schemes. The models are based on data from 200 intersections in urban areas in Kentucky. For each intersection, approaches with a left-turn lane were isolated and considered with their opposing through approach in order to examine the left-turn related crashes. This combination …

Transportation Network Companies: Influencers Of Transit Ridership Trends, Richard A. Mucci

Theses and Dissertations--Civil Engineering

The major transit systems operating in San Francisco are San Francisco Municipal (MUNI), Bay Area Rapid Transit (BART), and Caltrain. The system of interest for this paper is MUNI, in particular the bus and light rail systems. During the past decade transit ridership in the area has experienced diverging growth, with bus ridership declining while rail ridership is growing significantly (Erhardt et al. 2017). Our data show that between 2009 and 2016, MUNI rail ridership increases from 146,000 to 171,400, while MUNI bus ridership decreases from 520,000 to 450,000. Direct ridership models (DRMs) are used to determine what factors are …