Generally, police do have a great deal of discretion, both legal and  practical (i.e. there's little oversight) in terms of who they issue citations to. I do not believe that a police decision to NOT ticket someone is appealable. Furthermore, there's a legal doctrine called necessity: people can break the law in some instances when they have to save a life or prevent other harm. For example, someone could trespass to assist someone being assaulted or render medical care. In this case, it may be that trying to get a sick (or pregnant) spouse to the hospital is sufficient necessity.Note though that regardless of whether or not the other driver is ticketed, if he caused an accident, you could file a claim vs. his insurance or bring a civil lawsuit against him. If there's enough damage to justify it economically, you may wish to consult with an attorney to see if you have a viable case.