If the road surface or visibility is compromised in any way, such as by traffic congestion or bad weather, you must

drive at the posted speed limit
adjust your speed
use cruise control
drive with your hazard lights on

If the road surface or visibility is compromised in anyway, such as by traffic congestion or bad weather, you must :
D. drive with your hazard lights on
this way, other driver will be noted that you're experiencing a problem

hope this helps