high road

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The easiest or surest path or course.
• noun The most positive, diplomatic, or ethical course.
• noun Chiefly British A main road; a highway.

from the GNU version of the Collaborative International Dictionary of English.

• noun The most ethical and honest method; -- used mostly in the phrase to take the high road (as in an election campaign). Contrasted with low road.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun chiefly UK A main road or highway.
• noun idiomatic A course of action which is honorable, dignified, or respectable.