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 South Carolina, when a car crash or other incident involving multiple vehicles occurs, law enforcement officers have the authority to investigate all drivers involved for potential 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. South Carolina law, under statutes such as S.C. Code Ann. § 56-5-2930, prohibits driving a motor vehicle while under the influence of alcohol to the extent that one's faculties to drive are materially and appreciably impaired. The same applies to driving under the influence of any other drug or a combination of other drugs or substances which cause impairment. Law enforcement officers are trained to observe signs of impairment and may use field sobriety tests, breathalyzers, or other chemical tests to determine intoxication levels. If a driver is found to be in violation of these laws, they can be arrested and charged accordingly, regardless of their role in the incident.