This project comes from an analysis of the road tolls in Stockholm city in 2001. That study showed that the congestion problem on the roads in the area of Stockholm would fade away almost entirely, even with the calculated traffic levels for the year 2015, if a toll of 4 kr (approx. €0.42) per km was introduced in rush hour in the inner city and 2 kr (approx. €0.21) per km in the outer area of the city. This result was expected even though the traffic levels for 2015 were calculated to increase by 30% compared with the levels of today.

The study also showed that a toll of 2 kr per km in the inner city during rush hour combined with increased comfort in public transport would reduce the congestion and the traffic by almost as much as the higher toll. This result points at a package of road tolls combined with other measures and management means, that probably not would have the same effect separately, but together would give a synergy effect to decreased car traffic and on the negative environmental influence of urban transport.