I live in metro Melbourne and rarely drive in regional areas.
Today, I was driving on the Hume Freeway, and the rain was significant at times. Even though I felt it is quite unsafe to drive at the normal speed (110km/h), most drivers seemed to care less. I felt that I might lose grip. I ended up driving around 95-100km/h on the left lane to see vehicles piling behind me before overtaking.
What would you do in these conditions?
Think it depends on the car. I've got an 11 year old i30. Can barely see anything when it's raining so I drive slower. I've also got a 4 year old SUV, can see everything easily when it's raining so I drive at the posted speed.