Thesis (Ph. D.)--University of Rhode Island, 2004. / Typescript. Includes bibliographical references (leaves 233-243).

No description available.

Thesis (M.S.)--Ohio University, March, 1994. / Title from PDF t.p.

Thesis (M.S.)--Ohio University, March, 1998. / Title from PDF t.p.

Chevron pavement markings have seen rising interest in the United States as a means to reduce speeds at high-speed locations and improve safety performance. In Atlanta, there are two freeway-to-freeway ramps where chevron markings are being used. A previous study analyzed before-and-after speed data at these ramps and found only a modest reduction on overall vehicle speeds. However, a cursory crash analysis indicated that the ramps had crash reductions of over 60%, suggesting that safety benefits exist even though vehicle speeds are not significantly affected. This research aims to evaluate the safety performance of chevron markings on the two ramps in Atlanta, GA in order to quantify the potential impact of the treatment on safety and to understand the mechanism by which the treatment influences safety. This thesis begins with a literature review covering topics in human factors in safety, past uses of different types of pavement markings, and methods in using crash databases and police reports in accident studies. Next, the thesis presents an in-depth before and after analysis of crash data from crash databases and police reports provided by the Georgia Department of Transportation. And finally, the thesis concludes with a summary of findings and a discussion of further research needs. The results verified that there were 73% and 61% crash reductions in the two study ramps. Chevron markings appear to have benefitted all types of crashes and that they are possibly serving as a warning to drivers of potential upcoming hazards. Unavailability of a number of police reports and errors in crash databases were limitations to this study, and ultimately, new sites should be selected carefully and further studies need to be performed to better understand the treatment's benefits.

Thesis (M.S.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains viii, 86, 82 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 85-86).

Thesis (M.S.)--Ohio University, March, 1999. / Title from PDF t.p.

Thesis (MBA)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The study involved a detail empirical investigation into the different road studs in use on South Africa’s national road network and how they performed on the network under different road conditions in order to establish which road stud, under what conditions, offers best value for money in terms of life-cycle cost for the South African National Roads Agency Limited. These main questions were asked: What is the most cost-effective/value-for-money stud option for SANRAL to choose for each of the specified road categories? Under which conditions do the studs perform differently and what is the most likely mode of failure of specific studs linked to a specific road condition and road category? The South African and Australian road stud standards were reviewed to gain understanding of which criteria one has to consider when evaluating road studs and what information would be needed for the research. Similar studies on road studs were reviewed to compare the criteria that were looked at, namely Guidelines for the use of Raised Pavement Markers, developed by the Department of Transport in the United States, and Feasibility of using accelerated pavement testing to evaluate the long term performance of raised pavement markers, a research paper by the Florida Department of Transport. This research made use of a standardised questionnaire containing questions on various elements found to be key to the road stud performance. The study was done on approximately 4 659 km of roads in SANRAL’s Western region, consisting of the Western Cape and Northern Cape. From the literature review, it was identified that there is a need for the SABS standards to be updated to include the testing of structural properties of studs. SANRAL should look at the lack in specification requirements when asking for the installation of road studs. From the data available it was observed that the preferred studs were the Ferro Lynx followed by the STA+52 stud. They are predominantly used on the roads that were included in the survey. They perform well on the national roads. The data suggests that these two studs and the Rhino stud are the best-performing studs with the least dislodgement and loss in reflectivity. The STA+52 and Rhino stud, however, are fairly new on the market and more data for theirs full life cycle should be obtained for further monitoring The regression analysis indicated that 36 per cent of the variation in the reflectivity of the Ferro Lynx stud can be explained by the surface width of the road, the traffic volume measured as ELVS and the period installed. All the coefficients were significant with a 5 per cent significance. The prediction tables on the weighted data set, indicated that one should always consider width of road when choosing a road stud and that the reflectivity of studs deteriorates most on the narrower roads.

This thesis research investigated the predictive performance of pavement marking retroreflectivity measured under various conditions of continuous wetting. The researcher compared nighttime detection distance of pavement markings in simulated rain conditions and the retroreflectivity of the same pavement markings in several continuous wetting conditions. Correlation analyses quantified the predictive performance of the resulting retroreflectivity values from the continuous wetting conditions. The researcher measured the retroreflectivity of 18 pavement marking samples under 14 different conditions. The American Society for Testing and Materials (ASTM) has three standards for measuring the retroreflectivity of pavement markings under: dry (E-1710), recovery (E-2177), and continuous wetting conditions (E-2176). Using three ASTM standard conditions resulted in three sets of retroreflectivity data, and variations of the continuous wetting standard produced an additional 11 sets of continuous wetting condition data. The researcher also incorporated detection distance values measured for the same 18 pavement marking samples under three different simulated rainfall conditions at night. The three conditions included: high (0.87 in/hr), medium (0.52 in/hr), and low (0.28 in/hr) flow rates, these rates were to simulate typical rainfall rates in the state of Texas. The correlation analyses measures the linear relationship as well as the logarithmic relationship between the detection distance and the retroreflectivity of the pavement markings. A pavement markings' retroreflectivity is typically used as a detection distance performance indicator, therefore a high degree of correlation between retroreflectivity and detection distance would be desired. A high degree of correlation would indicate that a measured retroreflectivity value of a pavement marking would provide a good indication of the expected detection distance. The researcher conducted analyses for several subgroups of the pavement markings based on the markings type or characteristics. Dry, recovery, and all the continuous wetting retroreflectivity data were correlated to the detection distances. Correlation values found during this thesis research did not show a high degree of correlation for most of the subgroups analyzed. This indicates that measured retroreflectivity would not provide very good predictive performance of the pavement markings detection distance in rainy conditions.

No description available.