Browsing by Subject "Traffic"
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Item A method for estimating the inputs necessary to construct a microsimulation model using only publicly available data(2016-12) Van Hout, Alexander Joseph; Machemehl, Randy B.Standard traffic engineering methodologies rely heavily on traffic data collected in the field for the design and planning of roadways and intersections. This data can be used to build microsimulation models, which are versatile and realistic tools for analyzing traffic scenarios. Sometimes, however, time and budget do not allow for the collection of high quality data in the field, but answers to questions about traffic scenarios are still needed. This thesis provides a review of data that is typically available to the public online as well as existing traffic engineering methodologies that will be useful in manipulating that data. It presents an empirically derived method for estimating left turn, thru, and right turn counts at intersections based on tube counts on surrounding roadways and the characteristics of the intersection. It then presents an exploration of the distribution of directionality of traffic throughout the day. Finally, it presents a method for converting tube counts on an approach to an intersection to equivalent lane volumes so that signal timings can be estimated.Item Impacts of windmill traffic on pavement structures(2010-08) Grebenschikov, Sergey; Cicil, Architectural, and Environmental Engineering; Prozzi, Jorge Alberto; Prozzi, Jolanda; Machemehl, Randy B.This report focuses on the impacts of traffic generated as a result of the windmill on pavement structures. The wind energy industry is a fast growing sector of the U.S. economy. Lately concerns have been raised over the transportation of heavy windmill components on the pavement infrastructure. This report analyzes the impacts of windmill traffic on two pavement structures in Texas: 1) rural interstate facility, and 2) rural collector roadway facility. Windmill traffic was disaggregated by windmill component and categorized into eight vehicle classes. Two traffic scenarios were developed and a damage ratio for pavement rutting was developed. Based on the rutting damage ratio, results showed that windmill traffic has a significant impact on rural collector facilities when compared against normal truck traffic activity. Meanwhile, impacts on rural interstate facilities were determined to be insignificant when compared to normal truck traffic activity.Item Increasing online visitation to a travel website(2011-12) Rodriguez, Cynthia Marie; Wilcox, Gary B.; Mackert, MikeThe creation of a new travel website in the early 21st century can naively be mistaken as an easy open window to the world. LuminariaTravel.com is an online travel website recently created to inform visitors about San Antonio, Texas tourism. This paper seeks to analyze the challenges and offer solutions in entering an online market already entered. This paper presents insight into understanding the tourism industry online, and current marketing methods being used. In order for the small, privately-owned travel website to gain online visitors, LuminariaTravel.com must consider utilizing marketing tools for an integrated marketing plan. Luminariatravel.com must also be correctly positioned in the online travel market to have a unique stance and be able to communicate information that will set it apart from other San Antonio travel websites. This paper will include literature reviews and an industry case study. A final recommended marketing plan and strategy will be offered to LuminariaTravel.comItem Operational, supply-side uncertainty in transportation networks: causes, effects, and mitigation strategies(2009-08) Boyles, Stephen David; Waller, S. TravisThis dissertation is concerned with travel time uncertainty in transportation networks due to ephemeral phenomena such as incidents or poor weather. Such events play a major role in nonrecurring congestion, which is estimated to comprise between one-third and one-half of all delay on freeways. Although past research has considered many individual aspects of this problem, this dissertation is unique in bringing a comprehensive approach, beginning with study of its causes, moving to discussion of its effects on traveler behavior, and then demonstrating how these models can be applied to mitigate the effects of this uncertainty. In particular, two distinctive effects of uncertainty are incorporated into all aspects of these models: nonlinear traveler behavior, encompassing risk aversion, schedule delay, on-time arrival, and other user objectives that explicitly recognize travel time uncertainty; and information and adaptive routing, where travelers can adjust their routes through the network as they acquire information on its condition. In order to accurately represent uncertain events in a mathematical model, some quantitative description of these events and their impacts must be available. On freeways, a large amount of travel data is collected through intelligent transportation systems (ITS), although coverage is far from universal, and very little data is collected on arterial streets. This dissertation develops a statistical procedure for estimating probability distributions on speed, capacity, and other operational metrics by applying regression to locations where such data is available. On arterials, queueing theory is used to develop novel expressions for expected delay conditional on the signal indication. The effects of this uncertainty are considered next, both at the individual (route choice) and collective (equilibrium) levels. For individuals, the optimal strategy is no longer a path, but an adaptive policy which allows for flexible re-routing as information is acquired. Dynamic programming provides an efficient solution to this problem. Issues related to cycling in optimal policies are examined in some depth. While primarily a technical concern, the presence of cycling can be discomforting and needs to be addressed. When considering collective behavior, the simultaneous choices of many self-optimizing users (who need not share the same behavioral objective) can be expressed as the solution to a variational inequality problem, leading to existence and uniqueness results under certain regularity conditions. An improved policy loading algorithm is also provided for the case of linear traveler behavior. Finally, three network improvement strategies are considered: locating information-providing devices; adaptive congestion pricing; and network design. Each of these demonstrates how the routing and equilibrium models can be applied, using small networks as testbed locations. In particular, the information provision and adaptive congestion pricing strategies are extremely difficult to represent without an adaptive equilibrium model such as the one provided in this dissertation.Item Traffic tolerance and recovery of bermudagrass(Texas A&M University, 2005-08-29) Robinson, William DustanBermudagrass is the predominant turfgrass used for athletic fields in the southern United States. Numerous bermudagrass cultivars are utilized for sports field use. Two frequent variations in management among facilities include mowing and nitrogen fertility regimes. Research is needed to determine the influence of bermudagrass cultivar, mowing regime, and nitrogen fertility on traffic tolerance. Research conducted at Texas A&M Univeristy studied the traffic tolerance of Tifsport, GN-1, Princess, and NuMex Sahara bermudagrasses. These grasses were mowed once weekly at 3.80 cm and three times weekly at 1.90 cm and fertilized with 146, 292, 585, or 1171 kg ha-1 yr-1. Digital images were taken before and after simulated traffic to provide a quantitative value for percent coverage. Images were analyzed for percent green canopy coverage using Sigma Scan Pro. The number of green pixels was divided by the total image pixels a yielding a percent coverage value. Shoot density, visual quality, tissue water content, and tissue dry mass values were taken monthly. Percent tissue nitrogen was taken for three months. Analysis of digital images revealed variability in traffic injury tolerance between varieties. Tifsport, GN-1, and Princess maintained higher percent coverage than NuMex Sahara. GN-1, Princess, and Tifsport were able to tolerate traffic but did not maintain acceptable quality. Lower and more frequent mowing increased shoot density and visual quality for all grasses. Increased nitrogen fertility levelsincreased tissue succulence and tissue dry mass but did not affect the traffic tolerance of any variety. Increasing nitrogen fertility above 585 kg ha-1 yr-1 showed no benefit other than increasing visual color. This research provides a guide for managers to make informed decisions on cultivar selection and management practices under traffic conditions.Item Using telework and flexible work arrangements as a congestion mitigation strategy(2011-05) Brady, John F., 1986-; Machemehl, Randy B.; Zhang, Zhanmin; Zhang, MingCongestion is one of the most pressing urban issues Texans face today — it imposes steep social and economic costs on citizens and businesses and shows no sign of subsiding without substantial intervention. This thesis will argue that in the current environment of austerity and sharp political tension, it is of critical importance to implement low cost, politically amicable strategies to manage congestion. Flexible work arrangements like telework and flextime have been developed in the private sector as a cost-saving measure and as a reward for exceptional employees. When workers adopt a non-traditional schedule, the transportation network benefits as vehicles are removed or shifted from the peak period. Despite being widely available, non-traditional work arrangements are little used by employers and employees since both parties are uncertain if the new arrangement will benefit their career path and job security. Recently, public agencies and executives have launched programs and passed mandates that force or greatly incentivize employers to adopt flexible work arrangements. The case studies examined in this thesis show that modern programs can provide cheap, temporary congestion relief for urban areas while substantially benefitting the businesses and agencies who adopt them.