Under what condition can you drive slower than the posted speed limit on expressways?

Driving slower than the posted speed limit on expressways is permissible when it is unsafe due to hazardous conditions. Hazardous conditions can include severe weather (like heavy rain or snow), road hazards, or mechanical issues affecting the driver’s ability to control the vehicle safely. In such situations, it is essential for drivers to prioritize safety over adherence to the speed limit, as driving too fast in dangerous conditions can lead to accidents.

This understanding aligns with the overarching principle of road safety, which emphasizes that while speed limits are a guideline for safe driving under normal conditions, they must be adapted based on current circumstances. Hence, making safety the priority when conditions are not conducive to safe driving justifies the need for driving at reduced speeds.