Chicane: An artificial obstacle in a roadway, introduced to reduce traffic speed. Pronounced shih-KANE.
As its resemblance to chicanery suggests, chicane originally meant "to trick or deceive," and still does in some contexts. It comes from an Old French verb, chicaner, meaning "to quibble." In the 17th and 18th centuries, according to the OED, it meant "subterfuge." In bridge, a chicane is a hand without trumps; a double chicane is a chicane of both partners. The roadway sense arose in the mid-20th century, and is usually seen in the context of auto racing, where a chicane may be a movable barrier placed before a dangerous corner.
The city of Berkeley is fond of chicanes in residential neighborhoods—too fond, some disgruntled drivers say. Here's writer Michael Chabon's Ode to Berkeley, which appeared in the San Francisco Chronicle in 2004.
Berkeley's streets, though a rational 19th century grid underlies them, are a speed-busting tangle of artificial dead ends, obligatory left turns, and deliberately tortuous obstacle-course barriers known as chicanes, put in place to protect children - - who are never (God forbid!) sent to play outside.
Via Berkeleyside ("Berkeley and Brooklyn: An Eerie Similarity").
And here's an animation of chicanes in action: