- Illegal drugs or drug paraphernalia
- Open containers of alcohol (unless you are in a state that allows them)
- Firearms (in some states or jurisdictions)
- Weapons (such as knives, clubs, or brass knuckles)
- Hazardous materials (such as flammable liquids or chemicals)
- Stolen property
- Unregistered or uninsured vehicles
- Overloaded vehicles
- Vehicles with defective equipment (such as lights, brakes, or tires)
- Vehicles with excessive noise or emissions
- Animals (in some cases)
- Passengers in unauthorized areas (such as the trunk or bed of a truck)
- Oversized or overweight loads (without proper permits)
- Objects that obstruct the view of the driver
- Anything that may be considered a distraction to the driver
