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Description

Nighttime visibility of pavement markings is provided by glass beads embedded into the striping surface. The glass beads take light from the vehicle headlamps and reflect it back to the driver. This phenomenon is known as retroreflection. Literature suggests that the amount of the bead embedded into the striping surface

Nighttime visibility of pavement markings is provided by glass beads embedded into the striping surface. The glass beads take light from the vehicle headlamps and reflect it back to the driver. This phenomenon is known as retroreflection. Literature suggests that the amount of the bead embedded into the striping surface has a profound impact on the intensity of the retroreflected light. In order to gain insight into how the glass beads provide retroreflection, an experiment was carried out to produce paint stripes with glass beads and measure the retroreflection. Samples were created at various application rates and embedment depths, in an attempt to verify the optimal embedment and observe the effect of application rate on retroreflection. The experiment was conducted using large, airport quality beads and small, road quality beads. Image analysis was used to calculate the degree to which beads were embedded and in an attempt to quantify bead distribution on the stripe surface. The results from the large beads showed that retroreflection was maximized when the beads were embedded approximately seventy percent by bead volume. The results also showed that as the application rate increased, the retroreflection increased, up to a point and then decreased. A model was developed to estimate the retroreflectivity given the amount of beads, bead spacing, and distribution of bead embedment. Results from the small beads were less conclusive, but did demonstrate that the larger beads are better at providing retroreflection. Avenues for future work in this area were identified as the experiment was conducted.

ContributorsStevens, Ryan David (Author) / Underwood, Shane (Thesis advisor) / Kaloush, Kamil (Committee member) / Mamlouk, Michael S. (Committee member) / Arizona State University (Publisher)
Created2014
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Description
Highway safety is a major priority for the public and for transportation agencies. Pavement distresses directly affect ride quality, and indirectly contribute to driver distraction, vehicle operation, and accidents. In this study, analysis was performed on highways in the states of Arizona, North Carolina and Maryland for years

Highway safety is a major priority for the public and for transportation agencies. Pavement distresses directly affect ride quality, and indirectly contribute to driver distraction, vehicle operation, and accidents. In this study, analysis was performed on highways in the states of Arizona, North Carolina and Maryland for years between 2013 and 2015 in order to investigate the relationship between accident rate and pavement roughness and rutting. Two main types of data were collected: crash data from the accident records and roughness and rut depth data from the pavement management system database in each state. Crash rates were calculated using the U.S. Department of Transportation method, which is the number of accidents per vehicle per mile per year multiplied by 100,000,000. The variations of crash rate with both International Roughness Index (IRI) and rut depth were investigated. Linear regression analysis was performed to study the correlation between parameters. The analysis showed positive correlations between road roughness and rut depth in all cases irrespective of crash severity level. The crash rate data points were high for IRI values above 250-300 inches/mile in several cases. Crash road segments represent 37-48 percent of the total length of the network using 1-mile segments. Roughness and rut depth values for crash and non-crash segments were close to each other, suggesting that roughness and rutting are not the only factors affecting number of crashes but possibly in combination with other factors such as traffic volume, human factors, etc. In summary, it can be concluded that both roughness and rut depth affect crash rate and highway maintenance authorities should maintain good pavement condition in order to reduce crash occurrences.
ContributorsVinayakamurthy, Mounica (Author) / Mamlouk, Michael S. (Thesis advisor) / Underwood, Benjamin (Committee member) / Kaloush, Kamil (Committee member) / Arizona State University (Publisher)
Created2017