Why must hazardous materials sometimes be segregated (kept separated) during transport?

Hazardous materials must sometimes be SEGREGATED (kept separated) during transport because certain materials are INCOMPATIBLE — they could react DANGEROUSLY if they mix or are too close (causing fire, explosion, toxic gas, or violent reactions). CDL hazmat. SEGREGATION RULES (in a regulatory segregation table) specify which hazard classes must be kept apart (e.g., oxidizers away from flammables; acids away from certain other chemicals; cyanides away from acids — which would create deadly gas). The driver must load incompatible materials according to these rules (separated by distance or barriers, or not loaded together at all). Knowing why segregation is required (preventing dangerous reactions between incompatible materials) is core hazmat safety knowledge.