A load contains Division 5.1 oxidizer and Class 3 flammable liquid. Why must the driver check segregation rules instead of relying on package strength alone?

1. Oxidizers and flammables are never regulated when packaged
2. Strong packages always make segregation unnecessary
3. Strong packages can still leak in a crash, and incompatible materials may intensify fire or reaction hazards
4. Segregation applies only to rail cars