Stockholm Congestion Charge Trial (2006) — A Time-Limited Road-Pricing Experiment Settled by Referendum

Stockholm introduced a cordon charge on vehicles entering the inner city in a seven-month trial from January to July 2006, preceded by around 200 new buses and 16 new transit lines. Weekday fees ranged from 10 to 20 SEK per passage with a daily cap of 60 SEK; there was no charging at night, weekends or holidays.
Evaluations reported about a 20% fall in rush-hour car traffic to and from the inner city (stabilising near 22% versus 2005), congestion reductions of 30-50% on arterial roads, and lower particle and greenhouse-gas emissions. Roughly half of the drivers who stopped crossing the cordon switched to public transport.
Public opinion flipped: in autumn 2005 a majority opposed the trial, but after residents experienced shorter travel times a slight majority in Stockholm city voted in a September 2006 referendum to keep the charge. It was reintroduced permanently in August 2007.
Caution: the trial bundled the charge with large transit investment, so its independent effect is hard to isolate, and distributional and suburban-access concerns remained part of the debate.

Read the full analysis: https://transportportal.se/swopec/cts2014-7.pdf