Initial development and testing of a tool for removing graffiti from retroreflective signs

The goal of this thesis is to begin the initial development stages of a tool designed to allow a maintenance worker to clean roadway signs from the ground. Before this idea could be explored, it was first necessary to determine the current best practices for graffiti removal. To this end, a comprehensive literature search was performed, along with interviews with several individuals working in the field of graffiti removal. It was determined that, with the exception of signs along the roadway, graffiti removal techniques are largely well-developed and well-established. However signs, especially retroreflective signs, continue to be a source of difficulty in areas that are hard-hit by graffiti. Further interviews were conducted with sign maintenance personnel in Caltrans, and needs regarding graffiti removal from signs were identified. Development on the tool began, culminating in a final design proposal.;However, due to the sensitivity of the surface of the signs, it was determined that testing solely on the interface between the end effector and the sign needed to be performed. Thus the focus of the thesis shifted from overall development of the tool to specific design of the end effector in the form of experiments with different characteristics of the tool. The results of the experiments showed that, in order to avoid damaging the sign, the end effector must use a soft scouring pad type of removal medium. They also showed that it was feasible to continue development of the tool.