Neste trabalho são propostas pequenas alterações nos principais sinais de trânsito ( Parada Obrigatória – PO e Sentido de Circulação da Via – SCV) para melhorar a percepção dos mesmos por parte dos usuários. As alterações propostas são as seguintes: eliminação da orla externa vermelha do sinal de PO, aumento da orla branca do sinal de PO e da orla vermelha do sinal de SCV e emprego de suportes das placas com espessura significativa e coloridos. Além desses, também são parâmetros, dimensão das placas e dos suportes, bem como a cor e o formato do suporte. Para avaliação das diferentes parâmetros foi utilizada a técnica da psicofísica denominada de Método de Ordenação - Rank Order. As principais conclusões do estudo são as seguintes: a eliminação da orla vermelha das placas de PO melhora a percepção do sinal; o aumento da orla branca da placa de PO e da orla vermelha da placa de SCV contribuem para aumentar o impacto visual (os valores indicados situam-se entre 10 e 12,5% da largura da placa); as dimensões indicadas para as placas são de 70 e 80 cm de largura para placa de PO e de 60 e 70cm para placa de SCV. Os suportes devem ter dimensões entre 10 e 15 cm e devem ser pintados nas cores amarela ou vermelha. Uma observação relevante com relação à pesquisa: na definição das cores dos suportes, a questão estética-harmonia dos conjuntos não foi levada em consideração. / In this work there are proposed small alterations in the principal traffic signs (Stop Sign – SS and One Way Sign – OWS) in order to improve the perception of the same by a part of the usuaries. The alterations proposed are: the elimination of the external red border of the SS sign, the enlargement of the white border of the SS sign and of the red border of the OWS sign and the application of colored sign posts with a significant thickness. In addition to these, the signs and posts dimensions are parameters too, as well as the posts colors and shape. For the assessment of the different parameters a psychophysic technique named Rank Order was utilized. The principal conclusions of the study are the following: the elimination of the red border of the SS sign improve the perception of the sign; the enlargement of the white border of the SS and of the red border of the OWS sign contribute to improve the visual impact (the indicated values situate between 10 and 12,5% of the sign width); the indicated dimensions for the sings are 70 and 80cm of its width for the SS sign and 60 and 70cm for the OWS sign. The posts should have its dimensions between 10 and 15cm e should be painted in the yellow or red colors. An relevant observation related to the research: in the definition of the posts colors, the matter esthetics-harmony of the groups was not considered.

Neste trabalho são propostas pequenas alterações nos principais sinais de trânsito ( Parada Obrigatória – PO e Sentido de Circulação da Via – SCV) para melhorar a percepção dos mesmos por parte dos usuários. As alterações propostas são as seguintes: eliminação da orla externa vermelha do sinal de PO, aumento da orla branca do sinal de PO e da orla vermelha do sinal de SCV e emprego de suportes das placas com espessura significativa e coloridos. Além desses, também são parâmetros, dimensão das placas e dos suportes, bem como a cor e o formato do suporte. Para avaliação das diferentes parâmetros foi utilizada a técnica da psicofísica denominada de Método de Ordenação - Rank Order. As principais conclusões do estudo são as seguintes: a eliminação da orla vermelha das placas de PO melhora a percepção do sinal; o aumento da orla branca da placa de PO e da orla vermelha da placa de SCV contribuem para aumentar o impacto visual (os valores indicados situam-se entre 10 e 12,5% da largura da placa); as dimensões indicadas para as placas são de 70 e 80 cm de largura para placa de PO e de 60 e 70cm para placa de SCV. Os suportes devem ter dimensões entre 10 e 15 cm e devem ser pintados nas cores amarela ou vermelha. Uma observação relevante com relação à pesquisa: na definição das cores dos suportes, a questão estética-harmonia dos conjuntos não foi levada em consideração. / In this work there are proposed small alterations in the principal traffic signs (Stop Sign – SS and One Way Sign – OWS) in order to improve the perception of the same by a part of the usuaries. The alterations proposed are: the elimination of the external red border of the SS sign, the enlargement of the white border of the SS sign and of the red border of the OWS sign and the application of colored sign posts with a significant thickness. In addition to these, the signs and posts dimensions are parameters too, as well as the posts colors and shape. For the assessment of the different parameters a psychophysic technique named Rank Order was utilized. The principal conclusions of the study are the following: the elimination of the red border of the SS sign improve the perception of the sign; the enlargement of the white border of the SS and of the red border of the OWS sign contribute to improve the visual impact (the indicated values situate between 10 and 12,5% of the sign width); the indicated dimensions for the sings are 70 and 80cm of its width for the SS sign and 60 and 70cm for the OWS sign. The posts should have its dimensions between 10 and 15cm e should be painted in the yellow or red colors. An relevant observation related to the research: in the definition of the posts colors, the matter esthetics-harmony of the groups was not considered.

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.