Remember the experiences from other big cities when we test congestion charges in Copenhagen

Read the article in Danish Altinget 

An upcoming pilot project to get control of traffic in the centre of Copenhagen will give us good knowledge about motorists' behaviour and their willingness to pay for using the road. But the issue of congestion charges is far from simple. That is why we need to look at the successes and failures in other European cities. 

Congestion charges disguised as either minute- or kilometre-based charges or as a one-time payment for driving in the city can be the way to reduce the number of  cars in the city, secure better use of the capacity of the road network, and less congestion during rush hour and lower CO2 emissions. Particularly in Copenhagen, the debate has flared up again right now. Politicians, business, economists and environmental experts point out that congestion charges can help alleviate the problem of increasing traffic in Copenhagen.

But we can still recall the road toll ring failure during the Thorning government, which was cancelled in 2012. At that time, in addition to opposition from the population, it was the high costs and risks associated with establishing a toll ring around Copenhagen that made the project unviable. Although GPS technology, licence plate recognition and payment solutions have evolved significantly since then, congestion charges are still not a straightforward solution.

For these reasons, and linked to the Eldrup Commission, there is a proposal to carry out an experiment to clarify the effects of congestion charges in Copenhagen. The trial, which will be carried out in a collaboration between DTU and Sund & Bælt, will not use physical toll rings and barriers around Copenhagen, but instead use GPS technology, technology from the existing environmental zones and citizens who volunteer to participate in the trial. The experiment will give us important information about motorists' behaviour and willingness to pay congestion charges. But not all questions about congestion charges can be clarified in a pilot trial. Therefore, it makes sense to supplement the experiment with experience from other European cities that have already introduced congestion charges or that have had to throw in the towel.

Define the exact purpose of the project

In Edinburgh, congestion tax plans were shelved in 2005. This happened after the city's residents first supported the introduction of congestion charges and then turned against the idea. It turned out that in Edinburgh there was no clear and common understanding of the purpose of the congestion charge - neither among the people of Edinburgh nor in the administration. When we pilot congestion charges here at home, we must therefore be aware that congestion charges can be designed to support different purposes.

Depending on how you design the system and pricing models, you can either lower the total number of cars in the city, reduce the number of short 'convenience trips', distribute congestion more appropriately around the clock or ensure that motorists pay the real socio-economic costs of their driving. In Denmark, the plan is that congestion charges will reduce traffic by distributing it more evenly over the day. This means that we probably have to have a system where we pay per kilometre driven - or minute and where it is more expensive to drive during rush hour than outside rush hour. But there are also voices in the debate who primarily see congestion charges as a tool to reduce particulate or CO2 emissions or to secure extra revenue for infrastructure investment. Learning from the Edinburgh experience, we must be laser focused on the primary purpose when we test congestion charges in Copenhagen. If we do not do this, then it will be difficult to get support for the system, and difficult to establish a simple system where you can easily see what each trip costs. 

Supplement with other tool

Another key lesson from other countries is that congestion charges can be supplemented by a number of other tools, which make it more attractive to choose alternatives to the car.

In Stockholm, there have been congestion charges in the form of a toll ring since 2012, and it is estimated that the toll ring has helped to reduce traffic by approximately 18 per cent. But the payment ring has not done it alone. 

In Stockholm, the toll ring is used to increase the cost of driving into the city by car at certain times, while parking spaces at traffic junctions outside the city and enhanced public transport through the toll ring make it more attractive to choose public transport when entering the city.

However, it is not just measures that encourage the use of public transport that can supplement congestion charges. In a number of major European cities, the number of parking spaces in the inner city is being reduced, roads are being straightened, car-free zones are being introduced and speeds are being significantly reduced - all with the aim of making the car less attractive for trips into the city.

The measures are cheap to implement, but they are unpopular and inflexible because they affect everyone, for example business, at all times of the day. In a pilot trial, it will be difficult to simulate measures to supplement congestion charges, but by mapping and incorporating what other European cities have done, we can ensure that we learn from those who have succeeded in implementing congestion charges.

The upcoming pilot trial in Copenhagen is a good initiative that will make us significantly wiser about the use of congestion charges in Copenhagen. However, the issue of congestion charges is far from simple and congestion charges do not achieve everything alone. So it is important to remember to supplement the pilot trials with experiences from other European cities. There is no reason to believe that you can see all the evidence from your own experience.