PURPOSES : This study was purposed to investigate whether the current passing sight distance standard is appropriate. Therefore, to determine a safe passing sight distance, data collected from the observations of a two-lane road were implemented in reliability analysis to develop a realistic passing sight distance model. METHODS : First, passing sight distance data were collected for analysis from two-lane roads in Jeollabuk-do. Next, the speed profile was generated based on the collected data in order to analyze driver behavior. Finally, a model reflective of the driving behavior of motorists was developed and compared to the existing passing sight distance standard using reliability analysis. RESULTS : As compared to the existing model for safe passing sight distance, the actual speed of the overtaking vehicle indicated higher acceleration and a longer acceleration duration. The entire model, with exception of the d1 section, was modified to reflect the overtaking behavior of motorists d1. d2 was set to correspond to the time until the vehicles run side by side (t21); Time t22 was set to correspond to the time until subsequent recovery to the main lane, and d3 was set to range between 19 and 47 m following review of the actual passing sight distance data. In addition, d4 was computed to be two-thirds of the distance d2, and the oncoming car was found to drive at a constant speed that was similar to the speed associated with d2 . Analysis of the reliability of the existing Korean passing sight distance standard revealed that the current standard does not recommend a safe passing sight distance for drivers. CONCLUSIONS : As compared to the existing passing sight distance criterion, the actual speed and acceleration that driver apply to overtake a vehicle are higher, and the existing passing sight distance criterion is shorter than the actual passing sight distance. Additionally, the results of reliability analysis revealed that the proposed model developed to reflect driver overtaking behavior has more explanatory power than the existing one. Therefore, it is necessary to introduce new design standards that implement passing sight distance variables that are relevant to local drivers.