Sweden's ruling Social Democrat party may have been defeated on Sunday but one of its cherished public proposals succeeded against the odds. Stockholm voters narrowly approved an improved version of London's congestion tax. The win comes as a welcome boost for urban planners, economists and Greens who argue that such fees are essential for reducing 21st century traffic worldwide. But global gloating by congestion charge champions may be premature.

That Stockholm conducted a successful real-world trial earlier this year makes the victory that much sweeter. The idea won on its merits, not unproven promises. Traffic in the city centre dropped 20 per cent during the seven-month test; morning rush hour wait times fell nearly one-third while evening rush hour exit times were cut in half. Reality proved persuasive.