Paris

While in the U.S., bike-share systems are issuing threatening letters to parents who invent ways to tote their kids along, Paris is pioneering bike-share for the under-10 set. As far as we know, P'tit Vélib' is the first of its kind in the world.

Last week, Smart Growth America brought us the bad news: More than 47,000 people died while walking between 2003 and 2012. Most victims are killed on high-speed arterial roads. A disproportionate number are elderly or racial minorities.

Slow-speed zones are an increasingly widespread tactic to improve street safety and urban livability. Inspired by a German town that limited motor vehicle speeds to 30 kilometers per hour -- or roughly 19 miles per hour -- British activists have made 20 mph zones a core street safety policy across the nation.

Flashback to Europe, sixty years ago. Only still emerging from the ruin of total war, the continent was in the midst of a nearly unprecedented reconstruction. Over the next decade, however, industry finally was able to turn toward consumer products, from stockings to refrigerators and, of course, the automobile. Italians owned only 342,000 cars in 1950, but ten years later that number had increased to two million, according to historian Tony Judt. In France, the number of cars tripled over the decade.

As attention turns to the next federal transportation bill, and livable streets fans scan the platforms of presidential candidates for glimpses of what to expect from Washington over the next four years, Alex Steffen, editor and CEO of the blog WorldChanging, has posted an essay-in-progress called "My Other Car is a Bright Green City." Steffen says that reining in fuel standards and auto emissions, for instance, is not nearly as important to present and future generations as developing communities that behave more like cities, which are, by environmental measures, much cleaner than commute-intensive suburbs and exurbs. Here are some excerpts.

Transportation Alternatives' Noah Budnick and David Byrne prior to the Manhattan Borough President's "Manhattan on the Move" conference, October 2006.