Graduate Studies
First Advisor
Dr. Cody S. Stolle
Second Advisor
Dr. Ronald K. Faller
Third Advisor
Dr. Jennifer D. Schmidt
Date of this Version
Fall 8-31-2018
Document Type
Article
Citation
Treviño-Medina, T. 2018. Evaluation of Speed Tables on Roadway Curves. MS Thesis. University of Nebraska, Lincoln.
Abstract
The road network leading up to a U.S. military base is known as an Entry Control Facility, or ECF. Entry control facilities are used to shield military installations by monitoring vehicles and refusing access to unauthorized vehicles. The purpose of this research was to evaluate the use of speed tables in combination with roadway curves as a safe, passive method of guiding authorized users through ECFs, while delaying, disrupting, or damaging threat vehicles. First, simulations of a vehicle navigating a curve and traversing a single speed table were investigated using vehicle dynamics software, CarSim. The vehicle’s trajectory was analytically approximated using particle dynamics to find the speed-table-affected, turn radius. It was observed that a single speed table was ineffective. Therefore, multiple speed tables were considered. Speed table spacing on a curve was optimized for various combinations of turn radius and design speed based on occupant comfort at low speeds (25 mph or less), and suspension behavior at high speeds (40 mph or more). Vehicle performance and handling tests were conducted to calibrate the CarSim vehicle model and simulation results. A series of tests on flat ground were used to explore the vehicle model steering capacity at low-speed and near-slip conditions. The test vehicle was also remotely guided over three speed tables on an arc. It was observed that at speeds higher than 30 mph, the vehicle was launched from the speed table, and at 45 mph, the vehicle experienced tire bead failure and deflation. The disabling of the vehicle was repeatable and deemed a success; since, it increases the time that military staff have to deploy active barriers. It was recommended that a standard speed table spacing of 66 ft corresponding to a design speed of 45 mph for all curve radii be used until computer simulations can mathematically replicate damage. Further research was recommended to verify the performance of the speed table spacing on large turn radii (larger than 300 ft) and for very high speeds (greater than 60 mph).
Advisor: Cody S. Stolle
Comments
A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Mechanical Engineering & Applied Mechanics, Under the Supervision of Professor Cody S. Stolle. Lincoln, Nebraska August 2018.
Copyright (c) 2018 Tiffany Treviño-Medina