How do you make a slow vehicle let you pass on a narrow road?

[alecrain]

Today I was driving through Yarra Valley and the Dandenongs and pretty quickly I ended up behind a Toyota Corolla (or Crapolla as I like to call them) driven by an elderly woman, she wasn't exceeding 60km/h on a 100 km/h mountain road with no opportunities to overtake : , later I ended up behind a caravan : and on the way back behind some other slow car : , in few minutes there was a dozen of cars stuck behind us as well.

They wouldn't use the "slow vehicle turn out"

Now I don't want drivers that don't feel comfortable driving on a narrow, mountain road to risk their or someone else's lives but how do you make them realize that people behind them can drive safely faster.

Do you have a way of making them let you pass safely?