Briefly discuss the explanatory variables that may be needed when developing crash count models for intersections and road segments, respectively. Why should roadway links be divided into homogenous...

Briefly discuss the explanatory variables that may be needed when developing crash count models for intersections and road segments, respectively. Why should roadway links be divided into homogenous segments? How can the crash count modeling results be used? What are the methods often used in crash count modeling? What could be reasons that the predicted and observed crash counts are significantly different?