Jonas Eliasson: How to solve traffic jams


Jonas Eliasson – Director of the Centre for Transport Studies at Sweden’s Royal Institute of Technology


Congestion is a problem in all cities, regardless of how the city is designed. Whether European cities with a central core and few roads, or American cities with plenty of roads and an urban sprawl, all have congestion. As people investigate solutions, they boil down to discouraging people from driving during rush hour. When dealing with complex social problems, no one person can be responsible for it. The solution is to create the right framework and incentives and allow everyone to adapt to the new situation.

Stockholm is mainly congested at bridges entering the city, so they implemented a small charge of 1-2 euro at these bottlenecks during peak hour. This reduced traffic by 20%, which reduced it below the threshold needed to cause major congestion (which needs only a small decrease in traffic to drastically reduce congestion). The congestion charge stopped and started a few times, and traffic dropped by 20% the day it was introduced, and then increased the day it was removed. Importantly, the traffic numbers stayed down even after being implemented for a few years.

Public support for congestion charges improved over time. When first introduced, 70% of people opposed it. After a few years it flipped and 70% of people supported it. Surveys show that people feel they have not changed their minds, that they supported congestion charges all along. They also found that no-one feels like their transport mode has changed – they can’t identify the 20% who seemed to stop driving through the bridges. The effects of this price were subtle, nudging people towards making the desired decision rather than forcing it on them.

What this shows is that subtle cues: people have reduced peak hour car usage by 20%, gotten rid of congestion completely, and not only love it but feel like they supported the idea all along.

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