Quote Originally Posted by redorange
In thick fog the visibilty of your lights is not the same, what you consider to be flashing lights could also be interpreted as lights that appear and disappear because of the fog. Steady light does not always appear as steady light in thick fog where you can't even see more than 5-10 feet in front of you, so if a light appears a driver is more than likely to follow it thinking they are following traffic. See this news article about fog accidents.

"When it comes to weather in some parts of the San Joaquin Valley this weekend, fog is the biggest concern.

Karen Bailey of Brentwood and her family were skiing and got a look at what their drive home would be like Friday. "We all skiied to the top of Big Bear and stood looking over the valley engulfed in fog," said Bailey.

Many drivers are regarding fog with new respect after a huge pileup this week in Kern County. One person was killed in the series of crashes that involved 77 vehicles on Thursday.

The California Highway Patrol advises drivers to keep headlights on low beam so the fog doesn't reflect the light, reduce speed, avoid changing lanes, and to roll down the window to listen for traffic. Officers also say that if drivers need to pull over, they should turn off their lights so other cars don't follow."
But if you turn off your lights on the side of the road with minimum visibility, others following might not see you right away compared to having the hazard lights on. Maybe it really is a case to case basis depending on the situation.