Environmental Zones and the Impact of Car Use: Solving Air Quality Problems in Major Cities

Environmental Zones and the Impact of Car Use: Solving Air Quality Problems in Major Cities


R van den Brink, J Hoogeland, Goudappel Coffeng, NL; B Kampman, M Otten, CE Delft, NL


This paper assesses the effectiveness of different environmental zones in improving air quality inside and outside cities and the costs for government, residents, visitors and companies.


Like many European countries, the Netherlands has major problems to meet European air quality standards, especially the NO2 standard coming into force in 2010. Exceedances of this NO2 standard often occur on major inbound and outbound roads on the outskirts of major cities, and in the centres of these cities. In 2010 more than 100 kilometres of innercity roads and 500 kilometres of motorways will not meet the air quality standards. It seems difficult to solve all NO2 exceedances before 2010, and even in 2015 there remain some roads where NO2 concentrations are beyond the EU limits.

A very cost-effective measure to solve the problems is lowering the emission standards for new vehicles. However, EU countries are not allowed to apply their own emission standards for cars. A potentially effective measure that countries can take is to establish environmental zones where high emitting cars or trucks are no longer permitted. From 2007, several Dutch cities have established environmental zones for trucks. Several are now considering environmental zones for cars. These zones will have a number of effects. Firstly, they will lead to a cleaner car park, because some of the people affected will replace their polluting car with a cleaner one. Secondly, the amount of car traffic will diminish because not every resident or visitor will be willing or able to buy a cleaner car. These people have the choice between using another transport mode (public transport, bicycle), choosing another destination or not making the trip at all. All these changes will lower NO2 concentrations inside the environmental zone, but also outside because cars drive to and fro the environmental zone. First assessments show that an ambitious environmental zone for both passenger cars and trucks (vehicles older than 5 years are not permitted in the zone) could reduce the NO2 concentrations on ?hot spots? by 5 to 10 µg/m3 PM10 concentrations decrease by 2 µg/m3.

The behavioral changes caused by an environmental zone involve costs to people, financial (e.g., when buying a cleaner car) but also non-financial (e.g., when being forced to use public transport instead of the car). In addition, local governments must pay for the installation of cameras or other types of enforcement to detect high emitting vehicles, and businesses inside the zone may face economic damage.

The Dutch ministry of Housing, Spatial Planning and the Environment asked Goudappel Coffeng and CE Delft to assess the effects of environmental zones for passenger cars on the air quality inside and outside the environmental zone. Furthermore, we were asked to collect information on the costs for residents, and visitors of the environmental zone, the local government and businesses located in the zone. For this assessment two major cities and one smaller city were chosen as case studies. Three ambition levels were distinguished regarding the maximum emission level of cars still permitted inside the zone. The assessment was done for 2010 and 2015.

The design of the assessement was as follows:
- traffic models provided traffic volumes per road section, distinguishing between residents, visitors and people only driving through the zone;
- traffic volumes also distinguished between mobility motives (commuting, business, leisure, school);
- for each ambition level, group of people and motive the behavioral choices were estimated, using an expert panel;
- for every road section in the traffic model the change in average emission factor was calculated, as was the change in traffic volume due to the environmental zone.
- these adjusted traffic volumes and emission factors were put into an air quality model which calculated the average concentrations alongside all road sections and the number of exceedances of air quality limits.
- these results were compared with the reference situation, without an environmental zone.

This paper will draw conclusions on the effectiveness of the different environmental zones in improving the air quality inside and outside cities. Besides, the air quality effects are compared with the social costs caused by the environmental zones. This will provide information on the cost-effectiveness of the different environmental zones. The paper also focuses on legal, technical, administrative and ethical issues of environmental zones for passenger cars.


Association for European Transport