Engineering Commons^™

Optimal Scheduling Of Connected And Autonomous Vehicles At A Reservation-Based Intersection., Muting Ma

Electronic Theses and Dissertations

Reservation-based intersection control has been evaluated with better performance over traditional signal controls in terms of intersection safety, efficiency, and emission. Controlling connected and autonomous vehicles (CAVs) at a reservation-based intersection in terms of improving intersection efficiency is performed via two factors: trajectory (speed profile) and arrival time of CAVs at the intersection. In an early stage of the reservation-based intersection control, an intersection controller at the intersection may fail to find a feasible solution for both the trajectory and arrival time for a CAV at a certain planning horizon. Leveraging a deeper understanding of the control problem, reservation-based intersection …

Optimizing Work Zone Schedules Considering Traffic Diversion With Artificial Bee Colony Algorithm, Celina Semaan

Dissertations

Highway maintenance activities often decrease roadway capacity and intrude traffic movements. The need to finish the project on time and under a specific budget while minimizing the traffic congestion and complying with the emission standards requires an appropriate work zone schedule optimization. The objective of this research is to improve the efficiency of work zone activities and minimize the total project cost including maintenance, user, and emission cost.

While previous studies investigated the work zone optimization problem, they did not consider the implementation of emission standards nor applied a green diversion strategy. This dissertation analyzes the optimization of work zone …

Assessment Of Some Of The Common Practices Used In Scheduling Highway Projects, Jennifer Reyes

Theses and Dissertations

There are several factors documented in the literature that can affect the accuracy of estimated project durations in highway construction, such as weather, location, and soil conditions. Recently, the Texas Department of Transportation (TxDOT) raised a concern regarding some of the practices used when estimating the contract time for projects. This research presents an assessment of the effect that two practices identified have on the estimated project duration. These two practices include: 1) the estimated lead/lag times in project schedules and 2) scheduling with only critical or controlling activities. The effect of these practices is measured, primarily, by using four …

Methodologies For Solving Integrated Transportation And Scheduling Problems, Fereydoun Adbesh

Graduate Theses and Dissertations

This research proposes novel solution techniques to optimize two real-world problems in the area of scheduling and transportation. We first consider a model for optimizing the operations of dredges. In this problem, scheduling and assignment decisions are integrated across a finite planning horizon. Additional constraints and problem elements explicitly considered include, but are not limited, to environmental work window restrictions, budget limitations, dredge operation rates and schedule-dependent dredge availability. Our approach makes use of Constraint Programming (CP) to obtain quality and robust solutions within an amount of time small enough to be useful to practitioners. The expanded feature set of …

Cross-Elasticities In Frequencies And Ridership For Urban Local Routes, Joseph Totten, David Levinson

Journal of Public Transportation

Observational data from the Minneapolis-Saint Paul region’s Metro Transit were analyzed to determine the effects of service levels on ridership levels at different intervals. The research compares changes in service levels and ridership in several service intervals and includes elasticities and cross elasticities, or the influence that these service levels have on different service intervals’ ridership. These cross-elasticities were found to have little effect during the week; however, weekend ridership was found to be influenced by rush-hour and overnight frequencies.

Optimization Of Vehicle Routing And Scheduling With Travel Time Variability - Application In Winter Road Maintenance, Haifeng Yu

Dissertations

This study developed a mathematical model for optimizing vehicle routing and scheduling, which can be used to collect travel time information, and also to perform winter road maintenance operations (e.g., salting, plowing). The objective of this research was to minimize the total vehicle travel time to complete a given set of service tasks, subject to resource constraints (e.g., truck capacity, fleet size) and operational constraints (e.g., service time windows, service time limit).

The nature of the problem is to design vehicle routes and schedules to perform the required service on predetermined road segments, which can be interpreted as an arc …

Updating The Kentucky Contract Time Determination System, Timothy R. B. Taylor, Paul M. Goodrum, Michael Brockman, Barry Bishop, Yongwei Shan, Roy E. Sturgill, Kevin Hout

Kentucky Transportation Center Research Report

The Federal Highway Administration requires State Transportation Agencies to have a formal method to estimate contract time for highway construction projects. To meet this requirement many states use an integrated scheduling system to estimate project durations based on assumed productivity rates and generic job logic. The current work investigated the accuracy of two of these systems found that both systems accuracy in predicting the duration of Kentucky Transportation Cabinet projects was greater than +200%. In response to this poor accuracy, a parametric project duration estimating tool was developed based on a multivariate regression analysis of bid item quantities and engineering …

Development Of A Critical Path Method Specification And A Training Program For Use Of Cpm And Ktc, James D. Stevens, Donn E. Hancher, Ihab M. Hamdi

Kentucky Transportation Center Research Report

The Critical Path Method is a proven management technique used for determining the critical activities that would need additional care in any type of construction projects. The KTC requires that CPM schedules be used on selected highway projects. This research project offers a detailed idea on CPM scheduling application in highway construction projects, as well as current practices in other departments of transportation nationwide, together with specifications for proper application of CPM scheduling.