This is something I didn't know about Olympia. From the Boston Globe:

The pluses and minuses of cul-de-sacs have been the subject of quiet debate among city planners since the 1980s with the rise of the ''new urbanist" movement, which advocates walkable communities, according to Dennis Frenchman, a professor in the Department of Urban Studies and Planning at Massachusetts Institute of Technology.

A few communities have taken action. Ten years ago, Olympia, Wash., prohibited cul-de-sacs, except where the topography prevents street connections, according to Governing magazine. Baltimore County in Maryland did much the same thing five years ago, and Austin, Texas, pushed for subdivisions that were more walkable, attempting to ban cul-de-sacs in the late 1990s.

Norfolk is another community that has acted to discourage cul-de-sacs, beginning even before these other efforts. Back in the late 1980s, as Norfolk's farms and fields increasingly were taken over by single-family houses, the Planning Board decided to minimize the use of cul-de-sacs in subdivisions. Town officials did not want to ''isolate people into little pods," said Daniel Winslow, then the chairman of the panel. In his opinion, the effort paid off.

''Fast-forward almost 20 years later. As the neighborhoods have started to develop in Norfolk, we can now see what the impact of that regulatory change was," said Winslow, who pointed out the former cul-de-sacs on a drive through town this summer. ''Children can bicycle for miles and never leave a neighborhood street. They can visit their friends from other neighborhoods without going on the main roads. Residents can take walks that go somewhere. . . . There's multiple links into multiple neighborhoods, just knitting neighborhoods together"