First, London started charging cars a fee to enter the city center—a move widely credited with easing congestion and making it easier to get around in the crowded downtown. Now, the British government is considering instituting congestion pricing for the entire nation. Says this BBC article:

The London scheme brought in two years ago is reckoned a success in reducing traffic congestion, despite the fears voiced in advance. The daily charge for driving in the central zone is on Monday nearly doubling to xACxA38 ($14), and a big westward extension is being considered.

Last month, the British Transport Secretary, Alastair Darling, suggested something altogether more ambitious: a national system covering the whole country.

Drivers would be charged a varying rate per mile, depending on what kind of road they took. Cars would be fitted with a “black box” to record their movements, probably linked to global positioning satellites (GPS).

Mr Darling described it as “a radically different approach”, something that no other country in the world had done.

In some ways, this kind of approach may be expensive. Installing GPS “black boxes,” managing the tolling system, ensuring privacy, and the like will probably cost billions for a nation the size of Britain.

On the other hand, greater Seattle alone is facing transportation infrastructure costs—replacing (or scuttling) the Viaduct, repaving I-5, rebuilding state route 520, expanding I-405 and SR-167, financing the monorail & light rail—far exceeding $10 billion in current dollars, much of which will be paid through higher gas taxes. I’d wager that managing congestion with a pricing scheme would be far, far cheaper than building all of that new capacity.