[zaarn]

It's perfectly possible to overtake on a one-lane road without breaking the speed limit, it's something that is expected of your during the driving test if you drive behind someone sufficiently slow.

Even if you go into the lane of the oncoming traffic, you are still not allowed to break the speed limit.

If you're not part of the police, firefighters or ambulance drivers, I do not believe there is a single valid reason to break the speed limit.