"In any instance where the driver or the vehicle or both are found to be in serious violation of any federal safety regulation and thus pose an imminent hazard to public safety, the driver, the vehicle or both are immediately placed out-of-service by the inspector," the agency said in a statement.

"Even if a violation is not severe enough to place a company out of service immediately, companies are required to correct all violations for which they are cited, and minor violations can result in increased frequency of roadside inspections by state and local law enforcement," the statement added.