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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Direct user-charging of commercial vehicles for infrastructure cost recovery

Conway, Alison Jane, 1981- 10 March 2014 (has links)
The purpose of this research is to provide a theoretical framework for future commercial vehicle user-charging using real-time vehicle weight and configuration information collected using weigh-in-motion (WIM) systems. This work provides an extensive review of both mechanisms and technologies employed for commercial and passenger vehicle user-charging worldwide. Existing commercial vehicle-user charging structures use only broad vehicle classifications to distinguish between vehicles for the pricing of user-fees. The methodology proposed in this study employs highway cost allocation methods for development of an “Axle-Load” toll structure. A theoretical case study, based on information from Texas State Highway 130, is performed to explore the equity improvements that could be achieved through implementation of this proposed structure. Some sensitivity analysis is also performed to examine the potential revenue impacts due to uncertainties in different data inputs under existing and proposed structures. / text
12

Investigation of Environmental Impacts on Piezoelectric Weigh-In-Motion Sensing System

Hashemi Vaziri, Shahram January 2011 (has links)
Transportation by trucks plays a major role in North America’s economy. The growth of this industry will increase the loads on existing roads and highways and raises the possibility of overloaded vehicles, which causes significant damage to the pavement and consequently will reduce the lifespan of the roads. Weigh-in-motion (WIM) systems technology helps to address the challenge of overloaded vehicles. This technology provides traffic monitoring, collects data for pavement research and design, and improves the capacity of static weigh station operations. However, there is still a lack of knowledge about the behaviour of WIM sensors installed in different environments, which affects reliable and precise data gathering. More knowledge is required on proper installation procedures, pavement design for WIM systems, choice of sensor type for location, and calibration processes. This research is intended to explore the behaviour of WIM piezoelectric sensors under different loads and environmental conditions. Specifically, the effects of air and pavement temperature, and weight and speed of trucks are examined with respect to the estimation accuracy of WIM sensors. To accomplish this, three WIM systems composed of different piezoelectric transducers were installed at the CPATT test site at the Waste Management facility of the Region of Waterloo in 2007, and two WIM systems were installed between exits 238 and 250 on Highway 401 eastbound near Woodstock, Ontario. It was concluded that the output of the polymer piezoelectric sensor is influenced by temperature and weight factors but not by normally observed vehicle speed differences. While temperature can be compensated for, not enough information has been gathered yet does the same for weight factor. It should be noted that very low speeds (e.g. < 50 km/hr) result in significant errors for all the sensors, so that in congested sections WIM results should be interpreted accordingly. These results will be useful for investigating the effects of environmental conditions on other WIM systems and for predicting the responses of sensors in actual installation environments. This will assist in the recommendation of: (1) alternative and transparent calibration procedures for the WIM sensor systems, (2) and improved benefits of least expensive technology.
13

Utah Commercial Motor Vehicle Weigh-in-Motion Data Analysis and Calibration Methodology

Seegmiller, Luke W. 30 November 2006 (has links) (PDF)
In preparation for changes in pavement design methodologies and to begin to assess the effectiveness of the weigh-in-motion (WIM) system in Utah, the Utah Department of Transportation (UDOT) contracted with a Brigham Young University (BYU) research team to conduct an evaluation of their commercial motor vehicle (CMV) data collection system statewide. The objective of this research was to evaluate the CMV data collection program in the state of Utah and to make limited recommendations for potential improvements and changes that will aid in more detailed and accurate CMV data collection across the state. To accomplish the research objectives, several tasks were conducted, including: 1) a review of literature to establish the state-of-the-practice for CMV monitoring, 2) collection of WIM data for the state of Utah, 3) analysis of the collected WIM data, 4) development of a calibration methodology for use in the state, and 5) presentation of recommendations and conclusions based on the research. The analysis of collected WIM data indicated that the CMV data collection system in the state of Utah currently produces data consistent with expectations with a few exceptions. Recommendations for improvements to the CMV data collection system come in the form of a proposed calibration methodology that is in line with current standards and the practices in other states. The proposed calibration methodology includes calibration, verification, and a quality assurance programs.
14

Correlation Of Acoustic Emission Parameters With Weight And Velocity Of Moving Vehicles

Kolgaonkar, Amar 01 January 2005 (has links)
The thesis is motivated by the goal of doing initial investigation and experimentation for the development of Weigh-in-Motion (WIM) system using acoustic emission phenomenon. A great deal of research is going on for measuring the weight of moving vehicles. Weigh-in-motion of commercial vehicles is essential for management of freight traffic, highway infrastructure design and maintenance, and monitoring of heavy weight vehicles. The research work presents a methodology for correlating the weight of a moving vehicle with acoustic emission parameters (such as counts and energy). Furthermore, the correlation between the speed of vehicle with the acoustic emission parameters is developed. Preliminary analysis and experimentations were conducted for the study of propagation of acoustic signals in plate like structure and effect of dynamic loadings on Kaiser Effect. Initial testing revealed that there is a linear correlation between the impact force and the acoustic emission parameters. Also a polynomial regression of second order was found between the speed of vehicle and acoustic emission parameters. Road testing was conducted to investigate the correlation between weight of the vehicle and acoustic emission parameters. A linear relation was found between the weight of vehicle and acoustic emission parameters represented by counts, signal energy and absolute energy.
15

Operational effects of weigh-in-motion systems in weight enforcement

Weng, Ying 30 December 2008 (has links)
The effects of weigh-in-motion (WIM) systems on traffic operations and weight enforcement were compared and evaluated. The systems studied included high speed WIM, medium speed WIM and conventional static scales alone. The major measurements of effectiveness were traffic delay, queue, and the avoidance rate for overweight vehicles. Four weighing facilities from both the eastern and western United States were chosen as the real life bases for the study. Queuing theories, probability and statistics were the major methodologies employed in the study. The characteristics of queuing systems, such as traffic arrival patterns, weight enforcement processing time distribution, and capacity of the static scales at each weigh station were determined through field data collection at weigh stations. The proportion of the vehicle population directed to the static scale by WIM screening was analyzed, based on WIM accuracy and truck weight distributions at or near each weigh facility. By considering delay, queue, and the avoidance rate of overweight vehicles comprehensively, optimal weighing systems are proposed for different V/C ratios, i.e., the ratio of traffic volume at a specific site to the actual capacity of the static scale. When the V/C ratio is less than 1, a weighing facility using a static scale alone is most cost effective; when the V/C ratio is between 1 and 1.5, a medium speed WIM is suggested. High speed WIM is recommended only when the V/C ratio is larger than 1.5. / Master of Science
16

Fuel Consumption and Emissions of Turnpike Doubles in the Canadian Prairie Region

Baumgartner, Thomas Peter 06 April 2011 (has links)
This research analyzes fuel consumption and emissions of Turnpike double trailer combinations (Turnpikes) on a regional network in the Canadian Prairies. The research: (1) establishes current benchmarks for fuel consumption of Turnpikes and five-axle tractor semitrailers (3-S2s) with van trailers; (2) develops fuel consumption models for these vehicle types; (3) establishes an understanding of current operating characteristics of Turnpikes in the region; and (4) estimates their system-wide effects in terms of fuel consumption and emissions in Manitoba by applying the developed models. Canadian Prairie region-based carriers revealed an increase in Turnpike travel (from 2007-2009) of 44 percent after the twinning of the Trans-Canada Highway between Winnipeg and Regina in 2007 was completed. Turnpikes can save one third of fuel consumed when compared to 3-S2s; have higher fuel consumption in the winter months; and their use in 2009 reduced fuel consumption and CO2 emissions by five percent compared to 3-S2s.
17

Fuel Consumption and Emissions of Turnpike Doubles in the Canadian Prairie Region

Baumgartner, Thomas Peter 06 April 2011 (has links)
This research analyzes fuel consumption and emissions of Turnpike double trailer combinations (Turnpikes) on a regional network in the Canadian Prairies. The research: (1) establishes current benchmarks for fuel consumption of Turnpikes and five-axle tractor semitrailers (3-S2s) with van trailers; (2) develops fuel consumption models for these vehicle types; (3) establishes an understanding of current operating characteristics of Turnpikes in the region; and (4) estimates their system-wide effects in terms of fuel consumption and emissions in Manitoba by applying the developed models. Canadian Prairie region-based carriers revealed an increase in Turnpike travel (from 2007-2009) of 44 percent after the twinning of the Trans-Canada Highway between Winnipeg and Regina in 2007 was completed. Turnpikes can save one third of fuel consumed when compared to 3-S2s; have higher fuel consumption in the winter months; and their use in 2009 reduced fuel consumption and CO2 emissions by five percent compared to 3-S2s.
18

Post-calibration and quality management of weigh-in-motion traffic data

De Wet, Dirk Pieter Gerhardus 03 1900 (has links)
Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2010. / Thesis presented in fulfilment of the requirements for the degree of Master of Science in Engineering at Stellenbosch University / ENGLISH ABSTRACT: Weigh-in-motion (WIM) scales are installed on various higher order South African roads to provide traffic loading information for pavement design, strategic planning and law enforcement using a scientific approach. The two most respected international guideline documents for WIM systems are the American ASTM E1318 Standard and the COST 323 European Specification, yet neither are fully suited to be applied to local WIM systems. The author developed a post-calibration method for WIM data, called the Truck Tractor (TT) Method, to correct the magnitude of recorded axle loads in retrospect. It incorporates a series of powerful data quality checks. The TT Method is robust, accurate and adequately simple to be used on a routine basis. The TT Method uses the truck tractor loads of articulated 6- and 7-axle trucks with single steering- and double driving axles – these vehicle are called Eligible Trucks. Only Eligible Trucks with average axle loads between 6.5 t and 8.5 t are used in the calibration process – these vehicles are called Selected Trucks. A calibration factor, kTT, is determined using a fully automated iterative procedure, and multiplied with all axle load measurements to produce data for which the average truck tractor load of Selected Trucks, TTT, is equal to 21.8 t. The TT Method can be used for WIMs in various operating environments and is not sensitive to the extent of miss-calibration of a WIM, clipping of sensors owing to poor lane discipline or different extents of loading on different routes. The TT Method includes a series of data quality checks that can be used on a routine basis. They are summarised as follows: - The standard deviation of truck tractor loads for Selected Trucks, STTT, should always be below 2.0 t, but preferably below 1.9 t. - The standard deviation of front axle loads for Selected Trucks, SFTT, should always be below 0.9 t, but preferably below 0.8 t. - The post-calibration factor from the TT Method, kTT, should be between 0.9 and 1.1. The factor for any month should not deviate by more than 3% from the moving average of the previous five months. - The average of front axle loads of Selected Trucks, FTT, should be between 5.6 t and 6.6 t; the exact values are influenced by load transfer between the steering and driving axles. - A procedure was formulated using the Front axle / Truck tractor Ratio, FTR, to identify the percentage of Eligible Trucks that in all probability clipped the sensor. The percentage of these records must be below 10 %, but preferably below 6 %. The TT Method has the potential to significantly improve WIM data collection in South Africa. The calibration module of the TT Method, i.e. the procedure to calculate kTT, has already been accepted by SANRAL. Most of the data quality checking concepts associated with the TT Method were also accepted, although their threshold values are still being refined. / AFRIKAANSE OPSOMMING: Weeg-in-beweging (“weigh-in-motion”, WIM) skale word op talle hoë orde paaie in Suid- Afrika gebruik om op wetenskaplike wyse verkeersinligting te verskaf wat gebruik word vir plaveiselontwerp, strategiese beplanning en wetstoepassing met betrekking tot oorlading. Nie een van die twee vooraanstaande internasionale riglyne vir WIM sisteme, die ASTM E1318 Standaard en die COST 323 Europese Spesifikasie, is in geheel geskik vir Suid-Afrikaanse kondisies nie. Die outeur het ‘n unieke kalibrasie metode, genaamd die TT Metode, ontwikkel wat ’n reeks roetine kwaliteitsbeheertoetse vir WIM data insluit. Die TT Metode is eenvoudig, akkuraat en toepaslik vir ’n wye verskeidenheid WIM sisteme in Suid-Afrika. Die massa van trekkers van geartikuleerde 6- en 7-as vragmotors met enkel stuur- en dubbel dryf-aste en ’n gemiddelde asmassa tussen 6.5 en 8.5 ton (ook genoem Geselekteerde Vragmotors) word as verwysingsmassa gebruik. ’n Iteratiewe prosedure word gevolg vir die bepaling van die kalibrasie faktor, kTT. Dieselfde faktor word met alle asmassas in die data vir die analise periode vermenigvuldig, met die einddoel dat die gemiddelde trekker massa van die Geselekteerde Vragmotors, TTT, gedryf word na die teikenwaarde van 21.8 ton. Die TT Metode is ewe toepaslik ongeag die tipiese belading van trokke op ’n roete, hoe goed die WIM sisteem oorspronklik gekalibreer was of hoe goed laandissipline by die WIM sensor is. Die kwaliteitsbeheertoetse kan op ’n roetine basis toegepas word as deel van die uitvoering van WIM kalibrasie prosedure, en word soos volg saamgevat: - Die standaard afwyking van trekker massas van Geselekteerde Vragmotors, STTT, behoort altyd laer as 2.0 ton, maar verkieslik laer as 1.9 ton te wees. - Die standaard afwyking van voor-as massas van Geselekteerde Trokke, SFTT, behoort altyd laer as 0.9 ton, maar vekieslik laer as 0.8 ton te wees. - Die kalibrasiefaktor, kTT, moet verkieslik tussen 0.9 en 1.1 wees, en mag nie met meer as 3 % van die gemiddelde kTT vir die voorafgaande vyf maande verskil nie. - Die gemiddeld van voor-as massas van Geselekteerde Vragmotors, FTT, behoort tussen 5.6 ton en 6.6 ton te wees. Die presiese waarde hang af van die mate waartoe gewig tussen die voor-as en dubbel dryf-as oorgedra word weens dinamiese effekte op die trekker. - Die verhouding tussen die voor-as en dubbel dryf-as, bekend as die FTR, kan gebruik word as ‘n aanduiding of ’n trok weens swak laandissipline slegs gedeeltelik oor die WIM sensor gery het. Die persentasie gedeeltelike metings moet laer as 10%, maar verkieslik laer as 6 % wees. Die TT Metode het die potensiaal om die insameling en kwaliteit van verkeersdata deur middel van WIM sisteme noemenswaarding te verbeter. Die kalibrasie module van die TT Metode, m.a.w. die prosedure om kTT te bereken, is reeds deur SANRAL aanvaar. Die meeste van die kwaliteitsbeheerkonsepte wat met die TT Metode gepaard gaan is ook aanvaar, maar die drempelwaardes hiervoor word nog verfyn.
19

Options for providing quality axle load data for pavement design

Wood, Steven 30 March 2017 (has links)
This research evaluates four options to produce quality axle load data for pavement design: piezoelectric WIM sites (corrected and uncorrected data), static weigh scales, and a piezo-quartz WIM site. The evaluation applies four data quality principles: data validity, spatial coverage, temporal coverage, and data availability. While all principles are considered, the research contributes in the development and application of an integrated and sequential approach to assess data validity of the options by performing analyses to determine the precision and accuracy of axle load measurements. Within the context of Manitoba, the evaluation reveals that data produced by piezo-quartz and static weigh scales have superior validity, with piezo-quartz data offering better temporal coverage, data availability, and future geographic coverage. Ultimately, the selection of the best option for providing quality axle load data depends on the relative importance of data quality principles for producing data supporting sound pavement designs and infrastructure management decisions. / May 2017
20

Weight perception and the use of unhealthy weight loss tactics among adults in the United States: A Cross-Sectional study of NHANES data, 2000-2006.

King, Laura 01 May 2009 (has links)
Introduction: Weight dissatisfaction and misperception are widespread problems in the United States as are unhealthy weight loss practices. These negative body image issues can lead to eating disorders which have serious health and quality of life consequences. Objective: To evaluate the extent to which the prevalence of distorted body image and unhealthy dieting tactics exist in adults in the US and how these are related. Methods: Data from NHANES 2000-20006 on adults aged 20-59 was used. Weight perception was assessed with the physical exam measurements of weight status and the weight history questionnaire item asking if the person considered him or herself to be underweight, normal weight or overweight. Weight loss techniques were assessed with the weight history questionnaire items asking what methods they used if they tried to lose weight. Respondents were classified as having a weight perception discord if their perception was greater than actual weight status, and as having a concord in all other cases. Results: The total sample was 6,022. 10% had a perception discord and 15% used unhealthy weight loss practices. After adjustment, a significant relationship between a perception discord and behaviors was not found--this held true for both men and women. Discussion and Conclusion: Our results were similar overall to past studies; our inability to find a relationship could have been hampered by stigma associated with the subject matter. There are clearly other factors related to the adoption of unhealthy weight loss behaviors, which need to be determined.

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