Developing an understanding of the implications of traffic sign retroreflectivity guidelines for the province of New Brunswick

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University of New Brunswick


One of the high priorities held by most transportation agencies, at all levels of government, is the provision of effective traffic signs to make the operation of highways, roads and streets safer. Retro-reflectivity of those signs is a key determinant of their effectiveness, and in Canada, signing standards and guidelines are set at a national level by the Transportation Association of Canada (TAC). Guidelines for minimum retroreflectivity levels have recently been published by TAC in response to the standard adopted in the United States in 2007 through the Federal Highway Administration (FHWA). These proposed guidelines for minimum retroreflectivity imply that the various transportation departments need to evaluate their current position with their existing inventory of traffic signs and determine the number of signs that are non-compliant and, hence, the number they will potentially have to replace. In response, the New Brunswick Department of Transportation and Infrastructure (NBDTI) had the University of New Brunswick Transportation Group conduct a study to estimate the proportion of traffic signs that fail to meet the minimum standards of retroreflectivity and to estimate the cost of replacing those signs. Over 1100 signs were sampled throughout New Brunswick in the various NBDTI Districts. In addition to retroreflectivity levels, other data were collected that have potential to provide some explanatory ability to predict retroreflectivity degradation. Analysis of the data revealed the factors having statistical significance include sign age, geographic location (District), road class (where sign was inventoried) and the visual condition rating given in the field. Retroreflectivity of the signs was compared to the minimum levels established by the FHWA (since TAC guidelines were only published post-analysis). About 20 percent of the existing signs do not meet the FHWA minimum standards of retroreflectivity.