I suppose you mean "to save time"

"Spare" is used differently. You could for example say: "I'll come and see you as soon as I can spare the time", i.e. have enough time to do it. But this is not the meaning that makes sense here, Scriptor, or does it?
By the way, one must not confuse German "sparen" with "spare".

Another "false friend" word...
Thanks for correcting!

What means "to prolong the road" in this sentence? Can you explain the idea behind the sentence?

I suppose Scriptor means that you'll save time if you take the longer road. Think of traffic jams in the morning and all that. Being stuck in one might "prolong the agony" (http://oald8.oxfordlearnersdict...onary/prolong) but not the road. We'll have to find a way out of this one, Scriptor.
MAYBE A NATIVE SPEAKER COULD HELP ?

Good idea, raggione. But I'm not completely convinced. There is "one" in the beginning of the sentence. I suppose thus the sentence becomes a kind of proverb-like "eternal truth". In other words, the sentence is regarded as always true not only in the case of a traffic jam.

This is a Romansh proverb from the southern part of Switzerland, where there are high mountains. My own interpretation is:
The nearest way to the mountain top is straight up. But this requires a lot of dangerous and tiresome climbing. Therefore the fastest way to the top is to take the winding path instead.

Thank you, Scriptor!

Reminder.

"prolong" and "road" don't go together well, Scriptor. See http://www.ldoceonline.com/dictionary/prolong

I would suggest "You need to make the road long ..."

But we still need some NATIVE ADVICE.

Sometimes you save time by taking the longer road.

I know it probably doesn't match, but the English sounds more natural.