Abstract: An object monitor including two or more sensors for detecting two or more objects on two or more paths. Each sensor operates to detect location values of an object traveling along one of the paths. A processor receives first location values of a first object and calculates a first arrival time of the first object at a collision point. The processor receives second location values of a second object and calculates a second arrival time of the second object at the collision point. The processor operates to provide an alarm signal when the first arrival time and the second arrival time are within a safety difference value of being equal.