chatter bump
 n.— «One of her most unusual assignments was to build a road with all the wrong bankings. She created a four-mile nightmare of incorrectly canted curves, chatter bumps, potholes and a hundred other hazards found on rural highways. It’s [sic] use was to test the handling qualities of cars under the worst possible conditions.» —“Hoped Fashion To Be Her Field, But She Designs Roads” by David Chute in Highland, Mich. Vidette-Messenger (Valparaiso, Ind.) July 30, 1969. (source: Double-Tongued Dictionary)

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