"The Centre for Economics and Business Research, a London-based consultancy, and INRIX, a traffic-data firm, have estimated the impact of such delays on the British, French, German and American economies. To do so they measured three costs: how sitting in traffic reduces productivity of the labour force; how inflated transport costs push up the prices of goods; and the carbon-equivalent cost of the fumes that exhausts splutter out.
In America the average cost of congestion to a car-owning household is estimated to be $1,700 a year; in France it is $2,500. But traffic is so bad in Los Angeles that each resident loses around $6,000 a year twiddling their thumbs in traffic—at a total cost of $23 billion, the costs are estimated to exceed that of the whole of Britain. But these costs do not take account of the price of carbon-dioxide emissions. In total, over 15,000 kilotons of needless CO₂ fumes were expelled last year—which would cost an additional $350m to offset at current market prices. In choked-up Los Angeles $50m alone would have to be set-aside."