The city of Stockholm division of Transportation Administration has released an analysis of the congestion charging program it implemented in 2008 after a trial period in 2006. According to data from winter 2008 through 2009, traffic has fallen by 18 percent. The traffic reduction is lower than during the trial period (which was 22 percent), but still significant.
According to TrafficTechnologyToday.com:
The results of the latest study on the Stockholm Congestion Charging System, by the City Traffic authorities, shows that it has significantly improved access to the Swedish capital, by reducing queuing times on access roads to the city in the mornings by 50%. The study of the IBM-created system also shows that overall city traffic is down by 18% and CO2 emissions in the inner city have been cut by between 14 and 18%. In addition, the number of ‘green’, tax-exempt vehicles has almost tripled, with the study showing that the congestion charging system is the most influential factor in the decision to choose a ‘green’ car.
Based on current trends, the 10-page report notes operating costs are expected to be about 250 million kronor (25 million euros) per year while net revenues are projected to run about 600 million kronor (60 million euros) beginning in 2010. The net revenues are dedicated to improvements in the road system and network.
One of the biggest reductions in vehicle traffic come from vehicles that were driving through the congestion pricing zone. Twenty-eight percent of the vehicles traveling into the congestion zone were "exempted"--buses, alternative fuel vehicles, diplomatic vehicles, etc.
Notably, the proportion of vehicles exempted because they are alternative fuel vehicles increased from 3 percent during the trial period to 13 percent in 2008. MOreover, alternative fuel vehicles make 70 percent more trips into the zone that taxable (conventional) vehicles.
Overall, 96,000 fewer journays per taxable day were made by car in 2008 compared to the trial period, while public transport trips were up 45,000. Surveys indicate that half of the journeys not longer made by car are now through public transport.
Also, about 37 percent of the cars in the county paid the congestion charge at some point.