my father was hit by a state trooper

Under Indiana Law, governmental entities and public employees are excepted from the Indiana Comparative Fault Act.  Therefore, those entities or individuals are entitled to the defense of contributory negligence.  In the case of your father, any negligence found on his part would be a complete bar to recovery.  Had he been struck by a non-governmental employee, then Comparative Fault would have applied and the fault of both parties would be weighed by the trier of fact.  If your father would have been found to be 50% at fault or less, he would have recovered his damages, reduced by his percentage of fault.  If he would have been found to be 51% at fault or more, he would recover nothing, just as happened under the contributory negligence analysis.  Bottom line is that it is more difficult to prevail against a governmental entity in Indiana because of the contributory negligence defense.  A mere 1% of fault on the plaintiff means a win for the defendant.