ATTITUDES OF GREEK DRIVERS TOWARDS POSTED SPEED LIMITS Psarianos B. Professor – National Technical University of Athens – bpsarian@mail.ntua.gr Stamatiadis N. Professor – University of Kentucky – nstamat@engr.uky.edu Palaskas S. PhD Candidate – National Technical University of Athens – palaskas@survey.ntua.gr ABSTRACT One of the fundamental means for controlling speeds on a roadway is the presence of speed limits. A common practice has been to set speed limits at the 85 th percentile of operating speeds (V85). There is a suspicion however that operating speeds and design speeds are often not in agreement. Moreover, posting of speed limits based on operating speeds that are inconsistent with design speed can create potential safety problems. Posted speed limits that are higher than the design speed of the roadway may also have a safety impact. The establishment of a proper methodology for determining the appropriate speed limits is therefore imperative in improving both operations and safety of a roadway segment. A first step in this direction is an understanding of the drivers’ attitude and behavior towards posted speed limits. To accomplish this, an opinion survey of drivers of passenger cars and trucks was undertaken to determine their attitudes and behavior toward existing speed limits as well as indication of any crash involvement. The results indicate that a significant number of drivers exceed the current posted speeds, there were no differences among the various age groups of drivers, and few drivers have been involved in a crash. The major reason for not obeying speed limits is that the limits are not reflective of the roadway conditions and most drivers feel that they are lower than what the roadway can accommodate. The results were similar for drivers of both passenger cars and trucks. However, comparisons between local drivers and non-local drivers showed that local drivers are often those who violate the existing speeds. A review of practices in the United Kingdom and United States was also undertaken to supplement the efforts to develop a set of guidelines Keywords: speed limits, methodology, opinion survey, Greek roadways