• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3
  • 2
  • 1
  • Tagged with
  • 8
  • 8
  • 8
  • 8
  • 6
  • 3
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 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.
1

Roadside safety improvements

Estes, Carol Sue January 2010 (has links)
Digitized by Kansas Correctional Industries
2

An Integrated System for Road Condition and Weigh-in-Motion Measurements using In-Pavement Strain Sensors

Zhang, Zhiming January 2016 (has links)
The United States has the world’s largest road network with over 4.1 million miles of roads supporting more than 260 million of registered automobiles including around 11 million of heavy trucks. Such a large road network challenges the road and traffic management systems such as condition assessment and traffic monitoring. To assess the road conditions and track the traffic, currently, multiple facilities are required simultaneously. For instance, vehicle-based image techniques are available for pavements’ mechanical behavior detection such as cracks, high-speed vehicle-based profilers are used upon request for the road ride quality evaluation, and inductive loops or strain sensors are deployed inside pavements for traffic data collection. Having multiple facilities and systems for the road conditions and traffic information monitoring raises the cost for the assessment and complicates the process. In this study, an integrated system is developed to simultaneously monitor the road condition and traffic using in-pavement strain-based sensors, which will phenomenally simplify the road condition and traffic monitoring. To accomplish such a superior system, this dissertation designs an innovative integrated sensing system, installs the integrated system in Minnesota's Cold Weather Road Research Facility (MnROAD), monitors the early health conditions of the pavements and ride quality evaluation, investigates algorithms by using the developed system for traffic data collection especially weigh-in-motion measurements, and optimizes the system through optimal system design. The developed integrated system is promising to use one system for multiple purposes, which gains a considerable efficiency increase as well as a potential significant cost reduction for intelligent transportation system. / USDOT (U.S. Department of Transportation) / MPC (Mountain-Plains Consortium)
3

Development of alternative methods for delineating diverges in freeway work zones

Greenwood, Aaron Todd 06 April 2012 (has links)
Work zones are visually and physically complex environments, requiring that drivers maintain control of their vehicle and comprehend atypical and often discontinuous traffic control devices to safely navigate appropriate paths. Freeway diverges represent particularly difficult work zones areas. This thesis investigates current methods of delineating diverges in freeway work zones to determine important characteristics of these methods for future research. A virtual environment was constructed with two ramp geometries: a freeway continuing straight and one curving left. Still images of work zones on these geometries were created using drums spaced 10 ft apart, drums spaced 40 ft apart, drums spaced 40 ± 2 ft apart, and portable concrete barriers. These alternatives were used to construct temporary ramps that were either open or closed. 39 participants were asked to identify whether the ramp was open or closed and their responses were recorded to evaluate the performance of each alternative. Results indicate the importance of the Gestalt principles of closure, proximity, and continuity in perception of temporary exit ramps in work zones. These results will be used to guide future research into methods of delineating diverges in freeway work zones.
4

The role of a design engineer in safety of building projects

Vermeulen, Bernard 04 1900 (has links)
Thesis (MEng)--Stellenbosch University, 2014. / One of the causes for money to be wasted on construction sites is accidents. The reason is that an accident on site is an unplanned event typically relating to the loss of production or the loss of life. Many industry stakeholders and role players have focused on construction health and safety and to improve this area of concern; however, construction health and safety are not significantly improving. Construction still continues to contribute a large number of fatalities and injuries relative to other industry sectors. During the construction phase, poor construction health and safety performance is attributable to a lack of management commitment, inadequate supervision, and a lack of health and safety training and - systems. Health and safety systems do not only include excellent health and safety management on site, but rather an integrated approach on health and safety issues from the conceptual design phase by all stakeholders participating. This integrated approach includes the design done by the engineer. The inspiration behind this research is the question of whether South African Engineers design buildings safe for construction. The lack of knowledge by engineers with regard to construction processes, the lack of health and safety enforcement in the engineering offices and construction sites, and whether engineers adhere to safe design principles is the subject of investigation in this research. Therefore, this research aims to investigate the role of the design engineer in the safety of building projects. Specifically, it investigates to what extent the design engineer can contribute to site safety, and to what extent this is actually taking place. The Construction Regulations states the engineer can be appointed to act on behalf of a client and should share any information that might affect the health and safety of construction employees with the contractor. By means of a literature study, the investigation of case studies and the investigation of questionnaires to which a percentage of South African engineers responded, this research identified the information that should be shared by the design engineer with the contractor. The information can be shared by indicating hazardous activities or - locations on the actual drawings. Information can also be shared by specifying and reminding the contractor of certain health and safety hazards in the health and safety specifications of the building project. Although the Construction Regulations state that the safety hazards associated with most construction processes are the responsibility of the contractor, it will be beneficial for the safety of the employees if the engineer also consults the contractor on the hazards identified by him or her during the early design stages. Early collaboration between the engineer and contractor is also beneficial for the safety of construction employees. The result is an integrated approach towards safety hazard identification and mitigation. Having adequate knowledge with regard to construction processes allows the engineer to be aware of possible safety hazards. This will result in the correct information to be shared with the contractor and incorporated into the early design phases of the project to ensure a healthy and safe working environment. The study shows that a percentage of South African engineers have a lack of site experience, a lack of safety training, a lack of knowledge with regard to the content of the Construction Regulations, and a lack of knowledge with regard to construction processes. These shortcomings can be detrimental to site safety.
5

Investigation on road infrastructure, traffic and safety within the Port of Durban

Kunene, Oscar M. January 2013 (has links)
Submitted in fulfillment for the degree of Magister Technologiae: Engineering: Civil, Durban University of Technology, Durban, South Africa, 2013. / An increase in road traffic, poor road conditions and high numbers of road accidents are major challenges at the Port of Durban. Roads are considered as the most important transport mode at the Port of Durban. Road transport has taken almost 80% of the import and export cargo while railway transport is left with approximately 20%. It is estimated that 75 million lives in the world will be lost and 750 million people injured in road accidents in the first half of the 21th century. The Port of Durban is an important vehicle for facilitating economic growth of local, regional and national industries. For the Port to maintain global competitiveness with the current trend of globalization, it has to ensure that roads are well maintained, safe and have a smooth traffic flow with no delays. This study provides an overview of the road infrastructure within the Port of Durban in relation to road condition, safety, law enforcement and traffic. Existing and ongoing studies conducted in South Africa and abroad form part of the literature review. This study identifies factors that are affecting the condition of road infrastructure such as growth of container cargo, an increase in the dimension and weight of trucks, transport deregulation, port layout and handling equipments. Deregulation of road transport over the past years has resulted in an 80:20 split between road and rail transport putting more pressure on roads. Cost and time are the major deciding factors in the freight industry. Most customers prefer to use road transport due to the lower cost and reduced time compared to rail transport. There are eight major roads within the Port that connect the South, West and North of eThekwini Municipality namely Bayhead, Quayside, Maydon, Rick Turner, Wisely, South Coast, Bluff and Iran Roads. Asset verification and assessment of the condition of the existing eight major roads found that Quayside Road is in a better condition compared to the other roads. Maydon and South Coast Roads are low rated roads which are in a poor condition. Identification and assessment of the condition of 210 000m² of asphalt paved areas which included minor roads within the Port of Durban was also conducted. Most paved areas and roads fall under D (fair) category which is reasonable but maintenance work may be required within six months. Comparison between the condition of the eight major roads within the Port and outside the Port was investigated. The findings indicate that sections of roads outside the Port are in a better condition than sections within the Port. Traffic counts were conducted in order to determine the utilization of the existing eight major roads. Bayhead and South Coast Road are highly utilized roads. Road accident reports and death reports were analyzed on these roads. Most of the road accidents take place on South Coast Road. A questionnaire survey was conducted, targeting road users who travel on these roads within the Port. Feedback was obtained on the status of road conditions, safety and traffic within the Port of Durban. Findings of this survey revealed that most of the respondents don’t know where to report road defect/s within the Port. Approximately 37.5% of the road users felt not safe to drive on roads within the Port especially on South Coast Road. A high percentage of people (93%) witnessed accidents on these roads. Traffic signals within the Port are maintained by eThekwini Municipality and are very often non-functional. When road signs need to be repaired or replaced, it takes longer than expected. Also, there are limited parking areas around the Port resulting in trucks parking closer to the premises while waiting to collect or deliver cargo. This causes major traffic congestion, for example, on Maydon Road where most trucks park on the side of the road. Recommendations include assessment guidelines that could improve road condition, safety and traffic flow. Areas to be improved with regard to road infrastructure are also highlighted. / M
6

Safe Streets, Livable Streets: A Positive Approach to Urban Roadside Design

Dumbaugh, Eric 08 August 2005 (has links)
Transportation safety is a highly contentious issue in the design of cities and communities. To enhance community livability, urban designers, architects and city planners often encourage the placement of street trees, aesthetic street lights, and other roadside features in a buffer zone between the pedestrian realm and the vehicle travelway. While such designs clearly enhance the aesthetic quality of a roadway, conventional geometric design practice regards roadside features located in the clear zone as fixed-object hazards, and strongly discourages their use. This study examines roadside safety in urban environments to better understand the nature of urban fixed-object crashes, as well as the safety impacts of livable streetscape treatments. While the prevailing assumption is that livable street treatments have a negative impact on a roadways safety performance, the existing empirical evidence indicates that such designs are much safer than more conventional roadside designs. Current safety objections to the use of livable street treatments are not based on empirical evidence, but are instead the result of a design philosophy that systematically overlooks the real-world operating behavior of road users. This study details the origin and evolution of this philosophy, termed passive safety, and subjects it to an empirical test to evaluate its applicability to urban arterial roadways. It finds that passive safety assumptions do not meaningfully explain empirical observations of crash frequency and severity. To enhance contemporary geometric design practice, this study then proceeds to more thoroughly examine the nature and characteristics of urban roadside crashes, and proposes a new design approach, termed positive design that better addresses the twin goals of safety and livability.
7

Computer model to simulate truck accidents on exit ramps

Pajjuri, Srinivas Reddy 18 August 2009 (has links)
Though the trucks consist of only 3% of the total registered vehicles in the United States, truck accidents have been a major concern due to the property damage and loss of lives involved. Growth trends show that the truck travel will reach 1 trillion vehicle miles by the end of the year 2000. This increase in truck travel poses a major threat to the safety of both passenger cars and trucks. To improve the safety of the trucks as well as the passenger cars, understanding of the factors affecting the truck safety is essential. Models developed in the past were mostly regression models which tried to relate the truck accidents to the geometry of the highways. But most of these models did not consider all the factors affecting the safety of the trucks. Simulation models were developed in the past to study the dynamic vehicle response to different highway geometry especially, on exit ramps where most of the rollover accidents occur every year. But not enough research was done in the past on the weather and surface conditions affecting the truck safety. The objective of this study is to develop a graphics-based computer simulation model to test the trucks for different geometric features, surface conditions, and truck characteristics on exit ramps and to gain a better understanding of the factors affecting the safety of the trucks. A high-level simulation language SIMSCRIPTII.5 was used in the study to develop a simulation model. To make the model is to understand, graphical windows and animation were included in the model. Three exit ramps were tested in this model. Two of these ramps are existing ramps in southwestern Virginia and they had rollover accidents reported on them in the past. The parameters and other surface and geometric conditions can be changed at any time during the simulation. The model indicated that deceleration lengths provided may not be sufficient for heavy trucks traveling at higher speeds to reduce their speeds to the safe speed limits on the ramps. The posted speed limits may not be suitable for heavy trucks especially when the surface is not dry. The model also indicated that the tractor-semitrailers are more exposed to rollovers than any other type of trucks. / Master of Science
8

Development of an Improved Dissipative Passive Haptic Display

Reed, Matthew Robert 25 November 2003 (has links)
This project focuses on the design and modeling of a two degree-of-freedom dissipative passive haptic display. Haptic displays are man-machine interfaces that transmit forces to the human operator. A dissipative passive haptic display is one that may only remove energy from the system using actuators such as brakes and dampers, thus ensuring the safety of the human operator. These devices may be used to implement virtual constraints such as desired paths and obstacles. Traditional friction brakes have previously been used as dissipative and coupling elements in a two degree-of-freedom parallel manipulator, resulting in undesired effects such as vibration, stiction, and slow response times. Alternatively, the new robot is actuated by rheological brakes, which feature fast response times and smooth application of torque. This approach aims to improve upon the accuracy and feel of the previous design. A commercial magnetorheological (MR) fluid brake was selected and put through an extensive series of tests. The data was used to develop a model that characterizes MR fluid behavior in low speed braking applications. A parallel five bar linkage was designed and built that has separate configurations corresponding to 3-brake and 4-brake operation. The length of each arm was chosen by means of a geometrical optimization that weighs the size and area of the workspace and actuator effects. A simulation was then developed by incorporating the brake model into the equations of motion of the robot. Next, two forms of path following velocity control were devised and tested in simulation. Finally, the accuracy, workload, and smoothness of both controllers and both configurations were examined in preliminary tests with human operators.

Page generated in 0.1327 seconds