Driving above speed limit indicated on a road sign or by legal regulations, as well as driving speed unadjusted to specific circumstances are the most common causes of road crashes. Road safety is impacted not only by the driver, vehicle and/or road infrastructure, but also by the traffic experts who are in charge of assessing the road conditions and driver's obligations. Unadjusted speed of vehicles is caused by the lack of attention on the characteristics of the road, road signs, and posted speed limit for the vehicles in the opposite way. The aim of this master thesis is to analyze the speed limits on state road DC7, to determine their compatibility for both road directions, establish critical locations, and suggest enhancements to increase overall road safety on aforementioned road. To analyze data and determine critical locations, QGIS (Quantum Geographic Information System) and Base of the road traffic data of Croatian Road Ltd., are used. In this thesis, the unadjusted posted speed limit is divided into mild, low, medium and high. By the analysis it is determined that locations with mild unadjustment account for the lowest percentage (3.89%), while locations with low unadjustment account for the highest percentage (47.85%). Medium unadjustments are detected on 30.33% of the locations, while 17.93% locations have high unadjustments.