Road accidents are becoming a major cause for loss of life and property, and their number is showing a tremendous increase worldwide. One of the major steps through which road safety can be increased is by properly designing the road geometry. Reliability analysis was used as a tool for safety analysis of different systems. In highway analysis, deficiency in geometry results in undesirable manoeuvres which may not result in accidents, but is also considered as a failure of highway system. Application of reliability theory in highway analysis helps in considering the stochastic behaviour of drivers. The study considered 22 crest vertical curves located in northern districts of Kerala. The roads chosen were two-lane rural highways. Reliability analysis was conducted based on stopping sight distance, length of curve for stopping sight distance and length of curve for intermediate sight distance. Data pertaining to highway geometry, spot speed and accidents on the selected curves were used for conducting the reliability analysis. The accident data collected was transformed into Equivalent Property Damage Only (EPDO) and utilized as the metric for curve safety assessment. Reliability indices were determined and used to establish a safety evaluation criterion for crest vertical curves, representing their reliability. A Safety Performance Function was formulated for crest vertical curves based on these reliability indices.