On returning from his Christmas and New Year ski-ing holiday, Boris Johnson has made his first public appearance in London of 2012 at the Hammersmith flyover. This is presently closed because until unanticipated strengthening work is complete there is a danger that before too long it will fall down. Boris reassured motorists and local residents that "Transport for London will reopen this vital stretch of road as soon as they are able to do so."

The problems with the flyover are serious indeed and deserving of mayoral interest. Nonetheless, it seems a significant choice for Boris first photo opportunity of the year for another reason. Boris needs to keep Tory-leaning West Londoners sweet - having pleased many of them a year ago by removing the western extension of the congestion charging zone (WEZ), he won't want to look as though he's lost interest with another mayoral election on the way.

It's also a further example of Boris's eagerness to cultivate the support of motorists, having done his best throughout his mayoral term to protect their privileges despite the wealth of evidence that road traffic congestion does great cities great harm - even when their flyovers aren't disintegrating.

Here's what the Partnership for New York City calculated some years ago, as reported in the latest Cities of Opportunity report from Price Waterhouse Cooper (PWC):

It found that congestion in the greater New York City region added approximately $1.9 billion to the costs of doing business, led to $4.6 billion in unrealized business revenue, and cost some $5 billion to $6.5 billion in lost time and productivity, as well as an estimated $2 billion in wasted fuel and other vehicle operating costs. In total, the increasing problem of traffic congestion costs the New York City regional economy more than $13 billion a year, resulting in the loss of as many as 52,000 jobs annually.

As the Cities of Opportunity report notes, Boris's removal of the WEZ has ensured that the pain London endures from congestion has increased. Transport for London's new Travel in London report confirms its finding that "traffic entering the former zone increased by around 8 per cent...as a direct result of the removal of charging," and that there was "an attributable 7 per cent increase in the volume of circulating traffic." (page 199).

Meanwhile, across London as a whole average vehicle speeds have remained practically unchanged despite Boris's various "traffic smoothing" measures. As he himself said with admirable self-deprecation from an open bus platform in Ballymena they've been "increasing from 7.3 to 7.4 miles an hour."

Back to PWC's Cities of Opportunity:

Clearly, decreased congestion fundamentally improves most aspects of urban life. The problem lies in getting from here to there - from plainly unsustainable levels of urban gridlock to more viable patterns of urban transport, not only of human beings but of the goods and services that keep a city functioning.

Yet only the Green Party is proposing a solution. Like my photo says, expect delays.