The Colorado Rockfall Simulation Program (CRSP) is a computer program written in BASIC which models rockfall behavior and provides a statistical analysis of rockfall simulations at a given site. This analysis can be used as a tool to study the behavior of rockfall, determine the need for rockfall mitigation, and design rockfall mitigation measures. In order to model rockfall behavior, CRSP utilizes numerical input values assigned to slope and rock properties. The model applies equations of gravitational acceleration and conservation of energy to describe the motion of the rock. Empirically derived functions relating velocities, friction, and material coefficients are used to model the dynamic interaction of the rock and slope. The statistical variation among rockfalls is modeled by randomly varying the angle at which a rock impacts the slope within limits set by rock size and the slope characteristics. This program provides a site specific analysis of rockfall with output of velocity and bounce height statistics at various locations on the slope. CRSP is being used successfully to aid in the design of rockfall mitigation during the construction of Interstate 70 (I-70) in Glenwood Canyon, Colorado. The program provides a means for analyzing rockfall sites more objectively.