In a car crash or other incident involving multiple vehicles the police may investigate whether the driver of any of the vehicles is under the influence of or intoxicated by alcohol or drugs, and are not limited to investigating and arresting only the driver who was at fault in the accident, for example.
In Iowa, when a car crash or other incident involving multiple vehicles occurs, law enforcement officers have the authority to investigate all drivers involved for potential intoxication or impairment due to alcohol or drugs. This means that even if a driver is not at fault for the accident, they can still be subject to investigation and arrest if there is probable cause to believe they are under the influence. Iowa's Operating While Intoxicated (OWI) laws, codified in Iowa Code Chapter 321J, do not limit the scope of investigation to only the at-fault driver. Police can conduct field sobriety tests, request breathalyzer tests, and take other measures to determine if any of the drivers are intoxicated, regardless of their role in the accident.