Static warning signs are used to alert drivers of unexpected situations such as railroad crossings, icy bridges, falling rocks, and wildlife crossings. These types of unexpected, potentially hazardous situations are the cause of a high number of accidents. To improve the safety in these situations, departments of transportation need access to research on the effectiveness of the static warning signs and alternative measures that are available. This synthesis will provide the Montana Department of Transportation (MDT) with guidance on the effectiveness of conventional warning signs and identify other alternative signs/devices or practices that are effective in improving safety on Montana highways. The study will focus on warning signs that are used for occasional highway hazards such as wildlife crossings, ice, and falling rocks.