In the shortest, sweetest Streetfilm ever, a 24-second stop-motion animation, Elizabeth Press perfectly illustrates a chicane which is a sequence of bump-outs that force drivers to slow down and drive a more circuitous route along a straight, wide street. An added side benefit, chicanes also create more sidewalk space to be used for benches, tables, plantings and street furniture.
The word chicane comes from the German word schikane, meaning harassment.
Project for Public Spaces has more on chicanes and various other traffic calming techniques.